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am44mag
02-06-2019, 03:54 PM
I'm curious as to what you guys think of this. I've been hearing about people doing it more and more, but haven't really heard of any serious mishaps happening because of it. I believe the logic behind doing it is that the extractor will hold the case against the breech, so the round will headspace off of it instead of the case mouth (it also allows the firing pin to actually reach the primer).

I'm not suggesting anyone do this, or that it's safe, but beyond the blanket statement of "only shoot what cartridge your gun is chambered for", what are the possible dangers to doing this?

And before anyone asks, no. I do not plan on doing this regardless of whether it's safe or not. I do not own a 40 S&W, and 10mm brass is pretty inexpensive as it is, so there would be no benefit to me doing it. I'm just curious about it.

frkelly74
02-06-2019, 03:59 PM
I saw a man shooting 45 Gap in a 45 ACP back in the middle of the Obama ammo scare. It was what was available to them and it did work. Seems like it would not be good for yous extractors longevity though.

BK7saum
02-06-2019, 05:29 PM
Yes, it works and the .40 headspace off the extractor. .40 brass is free and 10mm isn't

gwpercle
02-06-2019, 05:56 PM
In these situations the extractor holds the case so the firing pin can hit the primer. The case is not headspacing on anything really....if the extractor is worn ...the gun wont fire.
Shooting rounds that are similar , in guns not chambered for them will probably lead to a broken or damaged extractor.
It happens a lot, 9mm Luger shot in 9mm Largo , 380 in 9mm Luger , 9mm luger in 38 Super, the list goes on . Again if the rounds are similar like , 40 S&W and 10 Auto , the danger would probably be more to the gun than the shooter.
But why take the chance of damaging a good pistol. In an emergency situation...maybe but as a rule just reload a lighter 10mm Auto round , buy another barrel or buy a 40 S&W ...too many better options than shooting the wrong ammo in a pistol and risk damage to it .
Gary

Texas by God
02-06-2019, 07:35 PM
My brother recently bought a long slide Glock 10 mm. We shot one box of 40 Smith & Wesson through it and it was a non-event. Perfect function, fired brass looked normal, and accuracy was okay. We filed this under "emergency knowledge."The case heads are identical so I'm not sure how the extractor could be damaged. I have seen heavy crimped .45 ACP that in no way they could headspace on the chamber mouth but yet they worked fine. I suspect the .45 GAP will too but unless someone gives me some I'll not do it.

Sent from my SAMSUNG-SM-G930A using Tapatalk

35remington
02-06-2019, 07:42 PM
Accuracy may be less than stellar with the bullet skipping off the chamber shoulder on its way downbore. Leading with cast is likely to be more pronounced. There is increased free travel for gasses to escape past the bullet on its way down the chamber that is too long for it.

country gent
02-06-2019, 07:43 PM
One other issue that may come up is the same as 38 spl in 357 and 44 spl in 44 mag. you may develop a carbon fouling ring in the longer chamber causing problems when the longer case is used. Normally the extractor is there and the case mouth cushions the pins blow. In this the firing pin is going to be taking the hit on its face from the firing pins hit. Probably not a big thing but not the way it was meant to work.

KVO
02-06-2019, 07:47 PM
If one were truly set on using 40 S&W brass in a 10mm auto, the best approach would be to load rounds long and set up to headspace off of the boolit engaging the rifling leade. i.e. when rounds drop in the chamber for a "plunk test" the case rim should be flush with the barrel hood as target 45 ACP loads are traditionally set up. My personal vote would still be to buy 10mm brass, it's cheap enough.

35remington
02-06-2019, 07:53 PM
Given the difference in length between the two rounds I am not sure that is possible with many bullets while still allowing sufficient case grip on what little of the bullet remains in the case.

376Steyr
02-06-2019, 10:33 PM
One possible scenario:
1. Take 10mm auto pistol and load magazine with 40 S&W ammo.
2. Insert magazine and rack slide
3. Pull trigger and hear "click"
4. Grunt in disgust, slap bottom of magazine to fully seat it, and rack slide again.
5. Have nose of round from magazine impact the first cartridge's primer. First cartridge wasn't held by the extractor, it was instead driven deep into the chamber, where the firing pin couldn't reach it.
6. Primer goes off from impact. Powder in first cartridge ignites. First cartridge fires in a totally unlocked and out of battery pistol.
7. Life suddenly gets interesting.

Elkins45
02-06-2019, 11:04 PM
I bought a 40 barrel for my 10mm Glock and had DougGuy throat it to accept a round with the bullet seated out to 10mm length. I can load to pretty much full 10mm power but use 40 brass that is basically free.

35remington
02-06-2019, 11:23 PM
Sounds like a candidate for 180s and 200s.

Elkins45
02-06-2019, 11:34 PM
The dummy rounds I sent him to fit it for were loaded with the NOE 200 grain WFN bullets.

35remington
02-06-2019, 11:37 PM
That’s verging on too much bullet for a standard length 40, certainly.

fatelk
02-06-2019, 11:39 PM
Personally I wouldn't do it, but I've heard and seen enough people doing it without problem to admit that clearly it is feasible.

This might be another of those things where you have people like myself on one side saying don't do it, sounds like a bad idea; and others on the other side that do it all the time without trouble.

I don't currently own a 10mm, but I guess it's a good thing to know in a pinch.

CLAYPOOL
02-06-2019, 11:54 PM
Well you can always use 10 mm brass and load lighter....Same with a .357. You don't need full power loads when fooling around..

cas
02-07-2019, 12:30 AM
Unfortunately the website is gone now, but there was a page with several photos of bad things that can happen (from a couple different guns). Hammered case heads, cases where the unsupported (lack of headspacing) allowed the primers to back out, then the cases traveled rearward and smooshed smashed the primers in all ugly ways and directions. Hairy stuff.

I suppose how dangerous it is really depends on your extractor and how tight to the breech face i holds the case. Some guns yes, some guns no. None for me thanks.

fatelk
02-07-2019, 02:18 AM
On a similar note, I was sorting some range brass recently and found a .380 that looked really ugly. The fired primer was seriously and dramatically flattened. I couldn't understand what could have happened to it. On closer look it seemed clear that it had been fired in a 9mm. My assumption is that the primer had backed out, then pushed back in and crushed badly as the pressure forced the case back. I don't know that any harm was done but it sure looked bad.

I do recall that I was told by one person that .40 ammo in a 10mm worked best in a Glock, because of the extractor. I don't remember the specifics. My BIL has a Glock 10mm, but he doesn't shoot it much and I've been collecting 10mm brass for him as I find it here and there.

am44mag
02-07-2019, 04:57 AM
One possible scenario:
1. Take 10mm auto pistol and load magazine with 40 S&W ammo.
2. Insert magazine and rack slide
3. Pull trigger and hear "click"
4. Grunt in disgust, slap bottom of magazine to fully seat it, and rack slide again.
5. Have nose of round from magazine impact the first cartridge's primer. First cartridge wasn't held by the extractor, it was instead driven deep into the chamber, where the firing pin couldn't reach it.
6. Primer goes off from impact. Powder in first cartridge ignites. First cartridge fires in a totally unlocked and out of battery pistol.
7. Life suddenly gets interesting.

Possible, but probably unlikely. The same thing could happen in any semi auto if you have a round that failed to extract and a new round tried to chamber. Flat nose bullets would likely make this a non issue as well.


Well you can always use 10 mm brass and load lighter....Same with a .357. You don't need full power loads when fooling around..

I believe the reasoning for doing this isn't just to have a lighter shooting round. Truth be told, most factory 10mm is anemic compared to what it is capable of doing. The main reasons I've heard for doing this is to save money, or because of the availability of 10mm ammo.

One of my favorite loads to shoot is a super light 10mm. I'm getting about 966 FPS out of a 4.5" barrel with a 180gr boolit. I also modified the gun (XDm) with a 22lb recoil spring since it would chuck brass from hot 10mm loadings into the next state. The ammo still cycles the gun, and the brass falls about 2-3 feet away. Recoil is negligible.

contender1
02-07-2019, 10:49 AM
Generally speaking, to answer the question; "Can it be done?" Short answer, "Yes, most likely."

The long answer is that it should be discouraged unless it's an emergency & a potential life or death issue.
Why?
Physics & how a gun is built & designed to work.
The basic difference in the 2 calibers in question is the OAL of the case, followed by the available power in the larger capacity case. Much as the 38 spl vs. the 357. Generally speaking, almost any firearm made to accept a 10mm will be able to handle the lower power of the 40 S&W. But,, looking at the physics of a rimless case, vs a rimmed one, and how each firearm is built makes one pause to consider the differences.
In general, they both are DESIGNED to headspace off the case mouth, whereas the 38/357 use the rimmed case to determine the headspace. The 40 S&W will not have the same support in a 10mm bbl, as the 10mm case will, while the 38/357 both receive the same support.

Sadly in todays world of so called "experts" we see all kinds of things done that should never be attempted. ("I drive better after a few drinks." "Sure it will work, I do it all the time." "I just load the powder in the case until the bullet compresses it a little, and never weigh any powder." "Reloading manuals are just a guide, I can load my stuff 10%-20% higher & I've never had a problem." And many, many other things we all know should not be attempted.)

Can it be done? Yes. Should it be done? Not necessarily.

KCSO
02-07-2019, 10:52 AM
Works till a case slips out of the extractor, then it doesn't. You decide how much you and your gun is worth.

scattershot
02-07-2019, 11:34 AM
Military Arms Channel on YouTube just released a video on this very subject. No problems. Long term usage may damage the extractor,though, IMO.

reddog81
02-07-2019, 12:25 PM
I've shot small amounts of 40 S&W out of my Glock model 20 and my Delta Elite. It works. The flat nosed bullets used in .40 and 10 won't ignite a primer if a case somehow gets lodged in the chamber. A new Glock extractor costs under $20. I don't make a habit of doing it, but I wouldn't be too concerned about it if necessary.

Lloyd Smale
02-08-2019, 07:42 AM
yup that's the real problem with doing it over the long haul. Ive done it in my 22 glock and it worked fine. But plan on using a wire brush on your chamber every time you do it and even then if your talking 10k rounds your going to probably end up with a rough chamber. As to extractor were or headspacing ill say this. Realisticaly all semi autos headspace on the extractor. If you loaded 10mm so that it actually head spaced on the rim it wouldn't take many rounds to gum the gun up and reduce reliability. Youd also have to trim brass regularly and I can honestly say I haven't trimmed handgun brass in 30 years. My guess is 99.9 percent of the ammo that goes through semi autos doesn't have the rim touching a thing.
One other issue that may come up is the same as 38 spl in 357 and 44 spl in 44 mag. you may develop a carbon fouling ring in the longer chamber causing problems when the longer case is used. Normally the extractor is there and the case mouth cushions the pins blow. In this the firing pin is going to be taking the hit on its face from the firing pins hit. Probably not a big thing but not the way it was meant to work.

35remington
02-08-2019, 08:39 AM
Lloyd, I measured for just that, not guessed.

The extractor rarely headspaces the round. Very very rarely. It is not hard to determine.

The amazing thing is no one bothers to check whether it is occurring before giving their opinion. It is not that hard to do yet no one does it. If they had tried to see if it was occurring pretty much nobody would be saying it.

As a practical matter when a round is fired in a semi auto using the correct ammo in the correct chamber the extractor is not doing the headspacing in the vast majority of instances, which is the reverse of your declaration.

Petrol & Powder
02-08-2019, 09:18 AM
Semi-auto, rimless cases do not "head space on the extractor" by design. Yes, the extractor may hold a casing that is shorter than the chamber against the breach face and allow that shorter casing to fire but that is not how that system is intended to work.

Rimless casings such as the 9mm Luger, 40 S&W, 45 ACP, etc. are designed to head space on the case mouth.

I think this falls into the category of things you can do but shouldn't.

Elkins45
02-09-2019, 01:11 PM
Before I had my custom throated 40 barrel I tried seating bullets long in 40 cases and shooting them in a stock 10mm barrel. I seated the bullet out far enough that essentially it was headspacing by the bullet resting on the rifling leade. In the first 50 rounds I fired I experienced two very strange hangfire incidents where there was a noticeable delay between the hammer fall and the ignition of the round. It’s way too much of a coincidence to imagine those were bad primers so I figured the case was too far forward and the primer just barely got enough of a tap to set it off on a ‘slow burn’ ignition. The gun in question was my S&W 1006.

I immediately stopped shooting those rounds in that gun. No reason to take the chance with my fingers IMO.

9.3X62AL
02-09-2019, 08:05 PM
I can understand people doing this in a "field expediency" or "emergency" scenario, but as a matter of common practice I have not and will not try it. I don't even shoot "Special" loads in "Magnum" revolver chambers anymore, because I dislike cleaning out the crud rings formed by this practice from the chambers. Well-fit brass is how I roll. The End.

Lloyd Smale
02-10-2019, 07:40 AM
may not be a theroretical design but its a practical fact. Any time you trim a case so it doesn't bump the camber mouth you headspacing on your extractor. trim a 1/4 inch off a 45acp and youll find they still run just fine in most 1911s and the same can be said for glocks sigs ect. Load those same rounds I something like a ruger Blackhawk 45 acp that doesn't have an extractor and you will see constant misfires and light primer hits. Tell me? Do you measure your chamber dimentions and trim your brass to exactly fit that chamber and bump up against the throat ever so gently. With a taper crimp I doubt you even could and if you could youd have to trim your brass to an exact length after ever shooting. WHO does that? Then if you did your ammo you custom tayored for that exact gun might be to long for your other 45. If you trim your brass short enough to work in any gun and the extractor didn't hold it in place youd get light primer strikes in everything. Just like you would see in a revolver. Santa or God doesn't hold that cartridge in the proper spot to insure your gun goes bang your extractor does. Even many bottle neck rounds work that way. especially if your using small base dies or bumping the shoulder back. Difference there is the shoulder still stops the case from expanding any bigger then the chamber. But in them you do have the ability to actually headspace on a shoulder. Most don't do it even in them though. Only real exception might be a belted mag set up to head space on the belt. No matter how short you trim or how far you set the shoulder back its still going to head space on the belt not the extractor. that is the real world not a technical explanation of theory. If it didn't 40 ammo sure wouldn't run in my 20 and 29 and it does just fine.
Semi-auto, rimless cases do not "head space on the extractor" by design. Yes, the extractor may hold a casing that is shorter than the chamber against the breach face and allow that shorter casing to fire but that is not how that system is intended to work.

Rimless casings such as the 9mm Luger, 40 S&W, 45 ACP, etc. are designed to head space on the case mouth.

I think this falls into the category of things you can do but shouldn't.

HATCH
02-10-2019, 08:56 AM
I have shot 40 cal out of my 1066 and 1006 (back when I had those pistols) and it functioned fine.
Keep in mind I only shot a mag worth out of each of them.

Petrol & Powder
02-10-2019, 12:40 PM
I'm sorry Lloyd but we're going to disagree on this.

Rimless casing may headspace on the extractor if the casing is too short to headspace on the case mouth but they are not intended to function that way.

fatelk
02-10-2019, 02:28 PM
Interesting; this explains why .380 will fire in a 9x18 Makarov. I once accidentally fired a magazine full of .380 through my CZ82 and only realized my mistake when picking up the bulged brass (though the complete lack of accuracy was a clue).

I wondered why they all fired so well, even though the brass is shorter and smaller all the way around.

35remington
02-10-2019, 02:32 PM
Lloyd, it is a misstatement to imply that since a case can be ground down to extra shortness so it can headspace on the extractor that this is what occurs with unaltered cases as the default condition.

The extractor lets a case go forward of the breechface quite a ways before it stops its forward movement. It has to, as a considerable gap must be present for the case rim to get between breech and extractor hook in feeding. If a considerable gap was not present the gun would not feed reliably. This gap must be much wider than the case rim. This gap prevents extractor headspacing from occurring. It is a very rare event.

Actual measurement, not guessing, using cases as they come from the factory or as commonly reloaded, in factory chambers intended for that cartridge, shows that extractor headspacing is something that really does not at all occur with any frequency. It is at best an extremely rare event.

There is no good reason for factory manufacturers to make a case super short, nor for reloaders to do so.

The idea that extractor headspacing is the default condition when correct ammo is used in chambers intended for it can be demonstrated to be very false if those arguing the point simply take the time to do some measuring.

Most do not bother, which is how mistaken beliefs get perpetuated. By all means do not take my word for it. Discover what is actually happening yourself.

Please note the term case rim, which is at the back of the cartridge, is distinct from the term case mouth, which is at the front of the cartridge. In the majority of instances with factory ammo in factory chambers it is the case mouth which is the headspacing surface. The extractor and rim are not part of this equation.

DougGuy
02-10-2019, 03:23 PM
I personally would not advise shooting 40 in a 10 except in two instances. First, test the 40 that you may have to use in a worst case scenario, this would be about plan D or so, but just to make sure it will defend you SHOULD the need arise and previous plans A through C fall through. Second instance, the need suddenly arrived and you grab the first magazine you see, and it happens to be 40, but it still works.... :bigsmyl2:

Walks
02-10-2019, 03:44 PM
When I had a Glock 20, I had a Wolfe bbl in .40S&W. It functioned fine ever time. It never occured to me to try .40S&W ammo in a 10mm Gun. Neither did I try it in my poor Colt Delta Elite. That gun went down the road after only 200rds of NORMA factory 200gr ammo. Loose as a goose. But in the Beginning of the 10mm's life, shooting NORMA 200gr ammo was the only way to get brass for reloading.

Fortunately the Glock .40's came out. I've had a Model 23 ever since. Got a Wolf bbl when they 1st came out. Then a 9mm Conv bbl.

I just don't understand the reason for trying to shoot ammo in a semi-auto pistol not chambered for it.

But I guess it's the same reasoning that had me jumping off the 2nd story roof with a patio umbrella when I was 8yrs old.

As far as shooting/cleaning longer chambers fired with shorter rounds. If you dry brush the chambers immediately after you finish shooting that gun for the day. Works best for revolvers.

It's a bit more with Lever Guns. But just twisting a too big wet patch/patches in a slotted tip pulled tight at the front of the chamber from the muzzle. And twisted back & forth a dozen times. Then followed by a couple/three dry patches the same way, solves the problem of "chamber crud build up". Ya gotta do it at the end of each days shooting.

These cleaning procedures worked very well with other Revolvers too.

9.3X62AL
02-10-2019, 06:04 PM
True that, Walks. That crud ring is just a pet annoyance of mine in wheelgun chambers. A First World problem, for sure.

rockshooter
02-10-2019, 11:44 PM
One thing I noticed firing .40 in a Glock 20 is that the cases hit me in the face all the time. I suspect that comes from the mass of the slide being so much greater in the 20. Other than having to duck cases, firing 40 in a 10mm works just fine for me.
Loren

Lloyd Smale
02-11-2019, 07:37 AM
I don't shoot 40s very often in my glocks but I have done enough testing to make sure it works. I guess my thoughts are (and I know its probably silly) that if **** and I needed too I could still feed my 10mms. My guess is 10mm ammo would be a pretty rare commodity. Now what makes it silly is I handload and have plenty of ammo but years down the line when im gone and my grandkids are still kicking they at least wouldn't have to throw the 10mm guns away. For the most part though if I want to shoot 40s I grab a 40 out of the safe. But in all reality its no different then guys shooting 38s out of there 357 (which I also don't do on a regular basis) . It sure isn't dangerous

baileyboy
02-11-2019, 11:18 AM
Well you can always use 10 mm brass and load lighter....Same with a .357. You don't need full power loads when fooling around..

What he said. Next we'll have some fools shooting 308s in a 30-06 !

fatelk
02-11-2019, 02:14 PM
What he said. Next we'll have some fools shooting 308s in a 30-06 !

Just for the sake of argument, it can be done. :)

Sig556r
02-11-2019, 02:24 PM
What he said. Next we'll have some fools shooting 308s in a 30-06 !

I inadvertently did, fireformed the 308 case till it ran out up to -06 shoulder.
Also fired a 380 on a 9, did eject but FTF.

Lloyd Smale
02-12-2019, 05:43 AM
but how could it possibly headspace??:kidding:
Just for the sake of argument, it can be done. :)

Peregrine
02-12-2019, 07:31 AM
What he said. Next we'll have some fools shooting 308s in a 30-06 !

I heard from a guy who worked at a gun store that once he had a gentleman walk up to him and ask where the 30-06 shorts where. Turned out the guy had been buying .308 for years and shooting it through his .30-06 but that one day couldn't find it because the packaging for his brand had changed slightly.

Also read about (I think here) an anecdotal case where a BAR was among several weapons being used for familiarization and fed several magazines worth of .308.
Functioned flawlessly until someone wised up. :oops:

Petrol & Powder
02-12-2019, 08:21 AM
Lloyd, we all agree that a rimless casing CAN headspace on the extractor. You seem to be the only one that thinks semi-auto pistols are DESIGNED to headspace the casing on the extractor.

35remington
02-12-2019, 12:16 PM
And it should come as no surprise that when correct ammo is used in in chambers intended for it in autoloading pistols, the ammo does not headspace on the extractor.

To proclaim that it does as a common event is contrary to what is actually occurring.

DougGuy
02-12-2019, 01:02 PM
Here is an interesting pair of barrels, sent by a member here that I think has posted in this thread already about using 40 brass and seating to 10mm COA. This job was to throat a 10mm barrel so it had freebore enough to handle anything that would cycle through the magazine, and throat the 40 barrel with enough freebore to feed and fire ammo loaded to 10mm COA dimensions.

10mm barrel on the left, long throated 40 S&W barrel on the right.

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/Glock%20Throating/DSC03908crop768_zps1r2bypzc.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/Glock%20Throating/DSC03908crop768_zps1r2bypzc.jpg.html)

Dummies sent in request to cut the throat deep enough to plunk these.

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/Glock%20Throating/DSC03877crop768_zpsl5liu2nm.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/Glock%20Throating/DSC03877crop768_zpsl5liu2nm.jpg.html)

35remington
02-12-2019, 01:47 PM
And before the above post gets misconstrued.....the rounds so loaded are not headspacing on the extractor either, as DG just cut a deeper throat. He did not move the location of the chamber shoulder in the 40 barrel.

Lloyd Smale
02-13-2019, 05:22 AM
nope never once said they were intentionaly designed to headspace on an extractor. But if you trim your brass, over crimp and even many guns with a bit long chamber rim then theory goes right out the door. If your gun is cut to headspace trimmed brass then not keeping it trimmed exactly to fit your gun is going to cause jams and if your gun is cut to handle longer cases (which most are) then a short case is going to headspace on the extractor. Belted mag rifle cases are designed to headspace on the belt too but how many handloaders actually do it?

So yes if you do trim your brass to fit each individual gun you have in that caliber to the exact length to bump the rim in your chamber you can say your headspacing on the rim IF your not over crimping. Me? Ive used mixed brass from many manufactures and have multiple 9s 40s 45s 10s and haven't trimmed a piece of handgun brass in 30 years. Never saw a piece of brass even fired 10 times not pass a plunk test. So obviously the shoulder in the chamber on most guns allows for some room and if so sure isn't headspacing a thing. Now ive seen guns that weren't cut like that. My neighbor who passed a few years ago bought two new springfield xd's many years ago when they first came out. Both were 45s and we took them to the range the day he got them and I grabbed a couple different loads I had loaded in coffee cans. Neither of those guns would run that ammo. We found for those two guns to work reliably brass had to be trimmed at least to minimum spec. Ive owned a few later xds and never had that problem so my guess is some of the early ones came out like that and it caused enough people to complain about reliability that they used a different reamer.

Just go and buy 5 different brands of 45 ammo and pull a bullet and measure each case and youll see variations in length. So unless theres some magic going on and the manufacture made a automatic adjusting shoulder in his chamber not all that ammo is going to headspace on the shoulder. Manufactures (at least ones that want reliability) have to cut chambers on the generous size to account for this and to account for the fact a gun gets dirty. Heck ive even came home after shooting a few hundred rounds through a gun with no trouble and when cleaning it found a ring of lead right at the shoulder in the chamber and the gun still went bang every time. IF the case was headspacing right on the shoulder it then would be headspacing on that ring of lead and it surely would cause problems immediately.

Heck ive shot a couple thousand rounds through my glocks without a cleaning and with lubed cast bullets and had them coated with gunk on in the chamber and they like the energizer bunny keep running an running and do it with any brass I find at the range. Maybe they do have a self adjusting shoulder I don't know about. So are they designed to run headspace on the shoulder? Nope that's not what the college grad ballistics experts who sit and design a new gun will say. But I don't put to much store in theory. In the real world the only time I worry about a semi auto handgun round being properly headspaced on the rim is in a ruger single action that has no extractor or moon clip to do that duty. Its why I don't have any convertible rugers anymore. I don't have the time or patients to trim brass and keep separate ammo for them. If I cant grab a coffee can of mixed brass ammo and go blasting and go blasting reliably its not worth my bother to own. Me? if I had to trim every piece of handgun brass even once id have wore out many power trimmers. Heck ive wore out a couple just doing 556 brass. Ive said my piece and am out of here. Ive got to cast some soft bullets so they can bump up in my guns today too. Because some expert told me it was nessisary[smilie=1:
Lloyd, we all agree that a rimless casing CAN headspace on the extractor. You seem to be the only one that thinks semi-auto pistols are DESIGNED to headspace the casing on the extractor.

Forrest r
02-13-2019, 07:20 AM
Slides and extractors are cheap enough. The primer will take longer to seal in the 40s&w case and the pitting ring from the hot gasses will happen faster/pre-mature. This is common with the use of srp in 9mm/40s&w and low power factor loads. Extractor replacement is easy enough/cheap enough.

I wouldn't shoot 40s&w's in a 10mm myself, bbl's are cheap enough.

Head spacing on the case mouth:
It's right up there with crimp/too much crimp. Anyone can do a simple test. Buy four different boxes of factory ammo & shoot 1/2 of each box with the extractor in the pistol. Note any ftf's and keep that brass separate to compare fp hits later on. Remove the extractor and re-test using the other 1/2 of each box of ammo. Note any ftf's and compare the fp hits to the brass that was fired with the extractor installed.


If the extractor is meaningless to a chambered round being fired:
There should be no ftf's (failure to fire) with or without the extractor installed.
The fp hits should have the same depth in the primers.
The fp hits should be centered.

Petrol & Powder
02-13-2019, 07:35 AM
Lloyd, you didn't say they (the guns) were designed to headspace on the extractor but you sure did imply that the extractor is more important to headspacing than the cut at the front of the chamber.

From post #24, "..........Realisticaly all semi autos headspace on the extractor"

Petrol & Powder
02-13-2019, 07:36 AM
And you implied it again in post #29, ".............Santa or God doesn't hold that cartridge in the proper spot to insure your gun goes bang your extractor does."

Petrol & Powder
02-13-2019, 07:40 AM
And you really hammered your view point home at the end of post #24:

Lloyd wrote : "yup that's the real problem with doing it over the long haul. Ive done it in my 22 glock and it worked fine. But plan on using a wire brush on your chamber every time you do it and even then if your talking 10k rounds your going to probably end up with a rough chamber. As to extractor were or headspacing ill say this. Realisticaly all semi autos headspace on the extractor. If you loaded 10mm so that it actually head spaced on the rim it wouldn't take many rounds to gum the gun up and reduce reliability. Youd also have to trim brass regularly and I can honestly say I haven't trimmed handgun brass in 30 years. My guess is 99.9 percent of the ammo that goes through semi autos doesn't have the rim touching a thing. "

So yes, I agree that you never explicitly stated that you believe the guns are designed to headspace on the extractor but you sure did make your opinion on the importance of the extractor a key point in the expression of your views.

Elkins45
02-13-2019, 08:57 AM
Here is an interesting pair of barrels, sent by a member here that I think has posted in this thread already about using 40 brass and seating to 10mm COA. This job was to throat a 10mm barrel so it had freebore enough to handle anything that would cycle through the magazine, and throat the 40 barrel with enough freebore to feed and fire ammo loaded to 10mm COA dimensions.

10mm barrel on the left, long throated 40 S&W barrel on the right.

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/Glock%20Throating/DSC03908crop768_zps1r2bypzc.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/Glock%20Throating/DSC03908crop768_zps1r2bypzc.jpg.html)

Dummies sent in request to cut the throat deep enough to plunk these.

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/Glock%20Throating/DSC03877crop768_zpsl5liu2nm.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/Glock%20Throating/DSC03877crop768_zpsl5liu2nm.jpg.html)

Yep, that person is me. The bullet shown seated in the dummy rounds is the NOE 200 grain WFP. FYI the "40 long" gets loaded using the low-end recommendation for 10mm and has functioned flawlessly so far. DougGuy did a fantastic job throating the barrels BTW. I wouldn't hesitate to recommend him if this is service you need.

35remington
02-13-2019, 09:06 AM
Lloyd, you also stated you never trimmed a handgun case in all your years of reloading. Post 24. Which means your cases as you use them are headspacing on the case mouth because you did not deliberately trim any super short.

You spent a great amount of text explaining in favor of something that is not occurring.

Do yourself a favor and do some measuring before arguing a point. The first thing to note is how far the extractor lets the case get from the breechface. Once that is noted, the fallacy of extractor headspacing is very evident. This saves laboriously typing out an erroneous response.

If you had done some measuring you would also know your contention that chambers are cut so sloppy that they allow the extractor to headspace is also not the case. Information trumps verbosity.

If your friend’s xd’s were not accepting cases, they had an undercut short chamber. These definitely were not headspacing on the extractor. Your arguments are contradicting themselves yet you do not recognize that they are.

What I am saying is not in the realm of theory. It comes from measuring actual guns and chambers and the fit of ammo in those guns. Since you have not done any measuring, the theoretical argument is the one you are making. Time to start measuring.

Sig556r
02-13-2019, 09:19 AM
I've never trimmed pistol brass either, even .357sig (factory or .40SW converts), but I agree with SAAMI & Sig that the round headspaces on the case mouth & not on shoulder, much less, on the extractor.

cwlongshot
02-13-2019, 09:35 AM
Wow..

A entire 3 page thread about nothing that really matters...and some strong opinions as if convincing another person on a forum was enough to require three pages to do so.

No dog in this convo as my opinion, like all, means nada. Because things work or don't work and the world spins regardless of what any of us "think". ;-)

I for one think its run its course. :drinks:

CW

35remington
02-13-2019, 10:18 AM
The troubling part is suggesting that this all can be resolved if some measuring was done, yet that person is absolutely determined not to measure anything. Opinion is a poor substitute for knowledge. It is possible to really not want to know how things work.

I will suggest my opinion means more than nada as I’ve made the attempt to resolve the issue with data from actual examples over multiple makes of guns.

Elkins45
02-13-2019, 10:26 AM
I've never trimmed pistol brass either, even .357sig (factory or .40SW converts), but I agree with SAAMI & Sig that the round headspaces on the case mouth & not on shoulder, much less, on the extractor.

SAAMI and the reloading manuals all say it headspace on the mouth, but apparently the people who chamber barrels do not agree. You will note that the headspace gauge pictured below does not have a case mouth. My experience in loading for the round since the mid-90's is that the barrel makers headspace it off the shoulder, and I actually had to grind the bottom off my RCBS sizing die so it would set the shoulder back far enough for my reloads to chamber in more than one 357 barrel.

https://www.realguns.com/images/nggabul.jpg

Lloyd Smale
02-13-2019, 10:32 AM
because in truth it is.
Lloyd, you didn't say they (the guns) were designed to headspace on the extractor but you sure did imply that the extractor is more important to headspacing than the cut at the front of the chamber.

From post #24, "..........Realisticaly all semi autos headspace on the extractor"

Lloyd Smale
02-13-2019, 10:33 AM
which it does
And you implied it again in post #29, ".............Santa or God doesn't hold that cartridge in the proper spot to insure your gun goes bang your extractor does."

Lloyd Smale
02-13-2019, 10:33 AM
hammer hammer!
And you really hammered your view point home at the end of post #24:

Lloyd wrote : "yup that's the real problem with doing it over the long haul. Ive done it in my 22 glock and it worked fine. But plan on using a wire brush on your chamber every time you do it and even then if your talking 10k rounds your going to probably end up with a rough chamber. As to extractor were or headspacing ill say this. Realisticaly all semi autos headspace on the extractor. If you loaded 10mm so that it actually head spaced on the rim it wouldn't take many rounds to gum the gun up and reduce reliability. Youd also have to trim brass regularly and I can honestly say I haven't trimmed handgun brass in 30 years. My guess is 99.9 percent of the ammo that goes through semi autos doesn't have the rim touching a thing. "

So yes, I agree that you never explicitly stated that you believe the guns are designed to headspace on the extractor but you sure did make your opinion on the importance of the extractor a key point in the expression of your views.

Sig556r
02-13-2019, 10:45 AM
SAAMI and the reloading manuals all say it headspace on the mouth, but apparently the people who chamber barrels do not agree. You will note that the headspace gauge pictured below does not have a case mouth. My experience in loading for the round since the mid-90's is that the barrel makers headspace it off the shoulder, and I actually had to grind the bottom off my RCBS sizing die so it would set the shoulder back far enough for my reloads to chamber in more than one 357 barrel.

https://www.realguns.com/images/nggabul.jpg

In deference your statement, I don't think Sig Sauer (I have them in 1911 nightmare, P229 & P226) chamber their barrels contrary to their design of the round. Not saying it can't headspace on the shoulder either, but that ain't the design intent. I too have loaded the round successfully but haven't got the need to grind my dies.

Lloyd Smale
02-13-2019, 10:46 AM
Do you measure out and perfectly trim brass in all your handguns after every shooting? If you do then judge me. But if you say yes its pretty obvious you spend much more time loading then actually shooting. Do you keep separate ammo for multiple guns in the same caliber? Ive got better things to do. I don't weight out every charge or clean primer pockets either. Shame on me. Me? id rather be shooting. Check seating dept with either a case gauge or plunk test in my tightest gun when I first loading and crank up the Dillon or lnl and fill a couple coffee cans and go shooting. Id have to be awful bored to trim handgun brass clean primer pockets or sort bullets by weight and as long as I can shoot I just don't get that bored. Aint my first rodeo. Ive been loading for 40 years and kind of think ive got a pretty good grasp after a few million rounds of handgun ammo what works and what doesn't and whats necessary and whats a waste of time. Local sheriffs dept uses 1000s if rounds of my ammo in there guns for practice and ive never heard a complaint by them either.
The troubling part is suggesting that this all can be resolved if some measuring was done, yet that person is absolutely determined not to measure anything. Opinion is a poor substitute for knowledge. It is possible to really not want to know how things work.

35remington
02-13-2019, 11:16 AM
Lloyd, if you want to know, start measuring. If you want to be in error, don’t.

It is just that simple. I have done what is needed to answer the question correctly.

Petrol & Powder
02-13-2019, 02:27 PM
Lloyd, can you share with us exactly how you believe a rimless cartridge headspaces in a semi-auto pistol?

marek313
02-13-2019, 03:07 PM
Long thread in a long line of can you shoot 40S&W in 10auto. I was asking the same question not too long ago. After doing my research online I decided to give this a shot and shoot 40S&W in my 10mm RIA 1911. I cant vouch for other guns but I have no problems at all. I do seat my 40s little long to close up the gap but so far so good after probably 500 rounds of 40S&W mixed in with 1K of 10mm. I keep my 10mm brass for medium to hot loads and shoot 40s for a nice soft round. Havent had any problems with my extractor or anything else yet knock on wood :guntootsmiley:

Lloyd Smale
02-14-2019, 08:12 AM
pretty simple they don't headspace. The extractor keeps the round from going to far forward and having misfires due to light primer strikes.
Lloyd, can you share with us exactly how you believe a rimless cartridge headspaces in a semi-auto pistol?

Lloyd Smale
02-14-2019, 08:29 AM
Lloyd, if you want to know, start measuring. If you want to be in error, don’t.

It is just that simple. I have done what is needed to answer the question correctly.

You never answered if you measure and trim every piece of pistol brass and trim it exactly to fit each individual gun and do it every firing. If you do your probably in the maybe one percent that do. plain and simple if your not doing it your not heaspacing on the rim of your round. Answer me this. If you trim your brass to minimum lengths given in a loading manual and your gun is a bit generous in its chamber what ARE YOU headspacing on? Do you really think every manufacture of every 9mm pistol made uses the exact same chamber reamer or even when one wears out use another EXACTLY like the first? Head spacing on the extractor might technically not be the proper term. Technically we as handloaders and even gun and ammo manufactures don't concern ourselves with headspace in handguns. they don't have a shoulder that might get fire formed so much that it fatigues brass like a bottle neck round might or cause a catastrophic case failure. So call it what you want. Load the way you want. But I know my guns go bang every time I pull the trigger and the rim doesn't have to contact a thing in that process.

Petrol & Powder
02-14-2019, 10:35 AM
pretty simple they don't headspace. The extractor keeps the round from going to far forward and having misfires due to light primer strikes.

So, Lloyd, you're going on the record and saying that rimless casings such as the 9mm and 40 S&W,.....DON'T HEADSPACE ?

You're saying that sharp ledge at the forward end of the chamber has nothing to do with head space ?

You're saying that if one were to remove the extractor and chamber a live round, that round wouldn't fire? Is that what you're saying, Lloyd?

marek313
02-14-2019, 11:21 AM
So, Lloyd, you're going on the record and saying that rimless casings such as the 9mm and 40 S&W,.....DON'T HEADSPACE ?

You're saying that sharp ledge at the forward end of the chamber has nothing to do with head space ?

You're saying that if one were to remove the extractor and chamber a live round, that round wouldn't fire? Is that what you're saying, Lloyd?

I think what hes saying that even though rimless casings are designed to headspace on the case mouth there are many short cases (Hornady comes to mind) where in fact case headspaces on the extractor and case mouth never touches the chamber. I dont know how often thats actually the case but I've heard few people make that claim now. If you keep breaking extractors i would definitely look into this but most guns and most brass thats probably very unlikely scenario. Maybe someone with more know how could do some research into that.

Elkins45
02-14-2019, 12:42 PM
So, Lloyd, you're going on the record and saying that rimless casings such as the 9mm and 40 S&W,.....DON'T HEADSPACE ?

You're saying that sharp ledge at the forward end of the chamber has nothing to do with head space ?

You're saying that if one were to remove the extractor and chamber a live round, that round wouldn't fire? Is that what you're saying, Lloyd?

I don’t presume to speak for Lloyd but what I take him to mean is that the extractor provides sort of a “pseudoheadspace” by preventing a short case from going so deeply into the chamber that it contacts the ledge. Without the extractor the round probably won’t fire, especially if tilted down. It might be more likely to if held straight up.

I wonder if it would fire if you removed the barrel, shoved a round under the extractor and dropped the hammer? I’m not crazy enough to try this, but it could probably be safely tested with an empty primed case...although the heavy bullet probably provides some inertia to help the case stay put long enough for the firing pin to fully dent the primer.

35remington
02-14-2019, 01:13 PM
Lloyd, I do not trim autoloading pistol brass.

Once again you are making a contradictory argument and you do not realize it. The first few sentences of post 68 are just that.

If a case is not trimmed, it is extremely unlikely to headspace on the extractor, because it will not be as short as possibly excessively trimmed brass. Hardly anybody trims autoloading pistol brass including, by your own admission, yourself. Your implication that longer untrimmed brass is more likely to be headspaced on the extractor speaks volumes, in that it makes it clear you do not have a very good grasp of the technical details of this topic and are thus ill equipped to discuss it.

Which, I suppose, explains the viewpoint that you have.

What is remarkable is how you are assuring me how everything works, yet you don’t bother to measure or check to see if your assertion holds any water or not. As I said, I measured the fit of my untrimmed, unaltered brass in my pistols. It isn’t headspacing on the extractor.

Manufacturers of firearms are members of SAAMI, as are ammunition makers. They are required as members of that organization to hold chambers and ammo within tolerances, and it is no surprise that they do. These tolerances in actual use see to it that headspacing on the case mouth is by far the most common situation.

What is also remarkable is how many people assume manufacturers cut chambers extra generously deep (the heck with SAAMI specs, apparently).....yet have never measured actual chambers to see if it is occurring.

Lloyd, this has pretty much run its course. What I am getting from your replies is you want to talk about theoretical things and make assumptions based on not actually finding out if they actually occur or not.

As for myself, this knowledge I have came about from reading and hearing about all the individuals on the net and elsewhere that repeated what they heard. When I asked if they had checked to see if this supposed extractor headspacing was occurring, most eventually admitted they had not, just as with your situation. None of those that had not had the faintest idea even how to determine if it was happening.

That sure didn’t prevent them from trying to speak knowledgeably about a topic that they had no knowledge of, or had any interest or ability to resolve correctly. This seems to be all too common, and such conversations find that individual defensively trying to steer the conversation toward what is believed rather than what is actually known by investigating.

Resolving the issue isn’t hard. But if you just don’t want to know, it would save a lot of print by saying that right up front. I can speak of exact clearances, technical data, and why I formulated ny understanding of how all this works, but the audience has to have an open mind, and the ability to realize that actually measuring beats theorizing about something they are clearly unsure about.

35remington
02-14-2019, 01:17 PM
An offer I can make is that for those with an open mind I can show, with pictures, exactly how all this is determined. Rocket science it ain’t.

Petrol & Powder
02-14-2019, 02:02 PM
I think what hes saying that even though rimless casings are designed to headspace on the case mouth there are many short cases (Hornady comes to mind) where in fact case headspaces on the extractor and case mouth never touches the chamber. I dont know how often thats actually the case but I've heard few people make that claim now. If you keep breaking extractors i would definitely look into this but most guns and most brass thats probably very unlikely scenario. Maybe someone with more know how could do some research into that.

Thank You, I'd like to hear what Lloyd has to say.

35remington
02-14-2019, 02:30 PM
The problem is.....how short does a case have to be to headspace on the extractor?

If you haven’t measured you have no idea. If you have, you do. One situation is clearly more useful than the other.

Here’s a hint.....much shorter than you probably think. Which is why it is a quite rare occurrence.

44MAG#1
02-14-2019, 04:53 PM
Speaking only, speaking only, only speaking of MY Glock M20. A Starline case when slipped uner the EXTRACTOR has NO detectable movement fore and aft. In fact it fit quite snugly. Still the gun functions with no problems.
Now with the case dropped into the chamber the head is not quite even with the barrel hood. The case sets very, very, very, very close to .005" under the barrel hood.
Now with that, even though Lloyd may not be technically correct for the number crunchers, he is correct, at least concerning my Glock M20 load her up and shoot the thing.


Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

44MAG#1
02-14-2019, 05:24 PM
Speaking only, speaking only, only speaking of MY Glock M29. A Starline case when slipped uner the EXTRACTOR has NO detectable movement fore and aft. In fact it fit quite snugly. Still the gun functions with no problems.
Now with the case dropped into the chamber the head is not quite even with the barrel hood. The case sets very, very, very, very close to .005" under the barrel hood.
Now with that, even though Lloyd may not be technically correct for the number crunchers, he is correct, at least concerning my Glock M29 load her up and shoot the thing.
Now this is with MY two Glock 10MM's.
Have not checked my Ruger 10MM 1911. Probably wont.


Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

35remington
02-14-2019, 06:26 PM
44 is this using a 10mm case? If it is the numbers make sense. If it is for a 40 case this may be reason for me to spell out how to check, for something obvious was missed.

In that instance I get the impression this is not being assessed correctly. I would guess most do not know what to look for.

44MAG#1
02-14-2019, 06:27 PM
44 is this using a 10mm case? If it is the numbers make sense.

Yes it is.


Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

44MAG#1
02-14-2019, 06:40 PM
Now before the 40 S&W case come into question while it drops much deeper into the Glock M29 the Starline 40 S&W case is a tiGHT fit between the breech face and the extractor just like the 10MM case does the 40 will headspace on the extractor. I fire 40 S&W in a 40 S&W and a 10MM in a 10MM.


Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

44MAG#1
02-14-2019, 06:43 PM
What was missed that would make the ammo of a 40 firing in a 10 the case has to headspace on something. IT CANNOT BE ON THE FRONT OF THE CHAMBER. PERIOD.
So that leaves the extractor.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

35remington
02-14-2019, 06:49 PM
Any case that stops in the barrel five thou below the hood is definitely not headspacing on the extractor. Thanks for the dimension measurement and the third party confirmation.

Anyone else care to check using the right ammo in the right chamber? It will take just a little time to see.

And no, what ever is happening is not extractor headspacing. I see I am gonna have to spell this one out.

35remington
02-14-2019, 06:53 PM
No one is questioning whether a 40 case will headspace on the extractor in 10mm. What is being discussed is whether proper ammo in the proper chamber headspaces on the extractor.

I think people get this wrong because they measure the wrong things.

44MAG#1
02-14-2019, 06:57 PM
Any case that stops in the barrel five thou below the hood is definitely not headspacing on the extractor. Thanks for the dimension measurement and the third party confirmation.

Anyone else care to check using the right ammo in the right chamber? It will take just a little time to see.

And no, what ever is happening is not extractor headspacing. I see I am gonna have to spell this one out.

I did not say that I said the case was .005" below the barrel hood while in the extractor. That is it just dropped into the barrel and then measured.
You are grasping at straws.
THERE IS A SNUG FIT OF THE CASE IN THE EXTRACTOR. NO MOVEMENT FORE AND AFT PERIOD.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

35remington
02-14-2019, 06:58 PM
Thanks for absolutely confirming your 10mm case in your 10mm chamber is not headspacing on the extractor. Case mouth headspacing is what it is doing. I understand you just dropped it in the barrel. I am not grasping at straws.

Anyone else?

35remington
02-14-2019, 07:01 PM
I think at this point you really need to ask me how I know that.

44MAG#1
02-14-2019, 07:01 PM
Thanks for absolutely confirming your 10mm case in your 10mm chamber is not headspacing on the extractor. Case mouth headspacing is what it is doing.

Anyone else?

First off I never said either way. You are grasping at straws. The extractor holds the case tight against the breech face.
Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

44MAG#1
02-14-2019, 07:01 PM
I think at this point you really need to ask me how I know that.

You dont know that.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

35remington
02-14-2019, 07:08 PM
Ah....finally we hit the point of contention, which is how people get this wrong.

“The extractor holds the case tight against the breechface.”

No, it does not. I’m afraid pictures are in order. Remember the contentious point is about proper ammo in proper chambers

44MAG#1
02-14-2019, 07:11 PM
Ah....finally we hit the point of contention, which is how people get this wrong.

“The extractor holds the case tight against the breechface.”

No, it does not. I’m afraid pictures are in order. Remember the contentious point is about proper ammo in proper chambers

I dont have to provide photos etc. to you or anyone else.
I dont care. I am telling you what I have found and what is going on. Take it or leave it.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

35remington
02-14-2019, 07:15 PM
No need to provide photos. I will, and it will clearly make my point. Stay tuned. This will show you that something other than what you think is going on.

Texas by God
02-14-2019, 07:25 PM
Since the shorter case cannot headspace on the chamber mouth the headspace measurement is essentially moved to the front of the rim. If headspace is required for a cartridge to fire, this is what is happening. The extractor holds the case rim tight while the chamber walls provide stability, providing all that is required for ignition. I could shoot .380 ACP, 9mm Luger, 9mm Steyr, 9x21 and .38 Super in my Astra 400. I shot a LOT of 9mm Luger in it with no ill effects. Back to the OP, yes you can shoot .40 S&W in a 10mm and all you'll get for certain is a dirty chamber.

Sent from my SAMSUNG-SM-G930A using Tapatalk

44MAG#1
02-14-2019, 07:29 PM
Since the shorter case cannot headspace on the chamber mouth the headspace measurement is essentially moved to the front of the rim. If headspace is required for a cartridge to fire, this is what is happening. The extractor holds the case rim tight while the chamber walls provide stability, providing all that is required for ignition. I could shoot .380 ACP, 9mm Luger, 9mm Steyr, 9x21 and .38 Super in my Astra 400. I shot a LOT of 9mm Luger in it with no ill effects. Back to the OP, yes you can shoot .40 S&W in a 10mm and all you'll get for certain is a dirty chamber.


Sent from my SAMSUNG-SM-G930A using Tapatalk

Amen. Who cares about the minute details? I sure dont. Some do to have fulfilment.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

cwlongshot
02-14-2019, 07:37 PM
:groner::groner:

35remington
02-14-2019, 07:50 PM
Does the extractor hold the case tight against the breech?

No. It can’t. If it did the gun would not feed. It has to allow the case rim to wander quite a ways forward of the breech before stopping its forward movement.

By actual measurement, the case head is forward of the breechface in the photo of the M and P 40 below by 30 to 33 thousandths of an inch. Other guns of various makes have similar gaps. They have to or they would not feed.

Most pistols these days have tight hood to breech tolerances, but even given a few thou clearance allowed, 44’s cases would have to be at least 20 to 25 thou shorter than they currently are to headspace on the extractor. Unless they were deliberately trimmed very short....you won’t find any that short.

44’s 10mm cases in his 10mm chamber are pretty clearly headspacing on the case mouth.

236019

Sorry it is a bit blurry, but the noticeable gap between case head and breech is pretty evident.

35remington
02-14-2019, 07:56 PM
2nd try

236021

35remington
02-14-2019, 07:59 PM
At this point, those that maintain that correct ammo used in correct chambers regularly headspaces on the extractor have a little wind taken out of their sails, I would guess.

35remington
02-14-2019, 08:01 PM
I would be quite happy to show a similar photo on the other makes of guns that I have.

35remington
02-14-2019, 08:04 PM
Incidentally, the 1911 has a wider gap of 40 to 43 thou. Again, the gap cannot be substantially smaller than that shown or the gun would be a jammomatic.

44MAG#1
02-14-2019, 08:04 PM
Try a Glock.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

35remington
02-14-2019, 08:08 PM
Already have. Same thing. Since you have a Glock, don’t take my word for it.

44MAG#1
02-14-2019, 08:11 PM
I dont.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

35remington
02-14-2019, 08:12 PM
Nothing beats looking into things yourself. It is too bad that others could not get to this point before this, but as I said it seems apparent that many did not know how.

Not so hard to do. I am delighted you don’t take my word for it. Maybe this will prompt you to look into things yourself now that you know how. I would rather people discover this on their own, and I stated as much several times here.

35remington
02-14-2019, 08:19 PM
There is no real point in being crabby, but I do see good purpose in knowing how things actually work.

ShooterAZ
02-14-2019, 09:14 PM
This thread has run it's course guys, let's move on.