Hot .40SW loads in 10mm converted to .40SW

[WilliamDahl]

If you have a semi-auto handgun that came in 10mm and could handle the full power 10mm loads (not the 10mm-lite FBI loads) and you bought a .40SW coversion barrel for it, would it be possible to load the .40SW rounds hot enough to match the full power 10mm rounds, or is there just not enough case capacity on the .40SW to do that?

[shotman]

should not be problem but best to mark cases so they never get used for the 40 . There is about 1 to 2 grs between the 2 anyway

[WilliamDahl]

According to Wiki, one commercial load for the 10mm gets 775 ft-lbs (155gr @ 1500 fps). The closest I found over on handloads.com is a 155gr @ 1450 fps (still a respectable 723 ft-lbs. I'm curious whether it would be possible to load a .40SW with enough powder to get 700+ ft-lbs without getting an "oops". The reason I'm curious is because I have plenty of .40SW brass, but 10mm brass is as scarce as hen's teeth around here. Of course, I would mark the rounds so that I did not accidentally load it into one of my weaker .40SW firearms. The only concern that I can think of is whether that bit of extra powder in the slightly smaller .40SW case would cause the pressure to rise too much.

[9.3X62AL]

I reload both calibers, and both run at fairly high pressures--in the vicinity of 33K PSI for most 40 S&W loads, and in the 37K PSI for the 10mm/200 grainers at 1200 FPS I hunt with. I use faster powders in the 40 than in the 10, and try not to strain either one past their safe upper limits. Having 41 Magnums, 44 Magnums, and 45 Colt/Rugers in the safe, getting adventurous ballistically isn't needed.

[Any Cal.]

I don't think it would be possible with most powders, they both work @ similar pressures, but the 10 has a bit more powder room. .40 loads already run @ max.

[subsonic]

No...

[garym1a2]

I would not do it. Just buy a few hundred 10mm cases and load them for SD or hunting. With 40 cases keep normal 40 safe pressures for practice.
My Glocks don't look that strong to push the limit.

[aarolar]

If you have a semi-auto handgun that came in 10mm and could handle the full power 10mm loads (not the 10mm-lite FBI loads) and you bought a .40SW coversion barrel for it, would it be possible to load the .40SW rounds hot enough to match the full power 10mm rounds, or is there just not enough case capacity on the .40SW to do that?

Why?!!

If you want 10mm power loads why not just put the 10mm barrel in it an use 10mm brass? [smilie=b:

[WilliamDahl]

Why?!!

If you want 10mm power loads why not just put the 10mm barrel in it an use 10mm brass? [smilie=b:

I explained that in post #3... 10mm brass is a bit scarce around here and it would be nice if you could just load rather hot .40SW in its place.

If we weren't the type of people who wondered "what if", we would just be buying commercial ammo, right? :)

[WilliamDahl]

I don't think it would be possible with most powders, they both work @ similar pressures, but the 10 has a bit more powder room. .40 loads already run @ max pressure. That being said, I do run .40 brass loaded to 1.260" OAL in a 10mm barrel with 10mm loads w/ no issues, BUT only in a Glock, which will not fire if the round somehow feeds ahead of the extractor. It causes the case to headspace on the extractor rather than the casemouth. It could probably work in other guns, but other designs may not be so forgiving in the case of a malfunction of some sort. The big concern is being able to fire the gun out of battery if there is a malf, but the Glock doesn't seem to be able to.

Is this OAL independent of the nose profile of the bullet?

[mstarling]

I have built two 1911 based 40 S&W pistols. Both have very high quality sides (Colt Delta Elite and Baer), and fully ramped Nowlin barrels. I load 40 S&W long and use 10mm magazines.

One is a comp gun and the other is not.

I definitely load hotter than normal 40 S&W. In one experimental run I achieved 1580 fps with 135 gr Nosler HPs. Brass and primers were fine. They left dents in T1 armor steel poppers. Came to the conclusion that such a load simply was not needed!

1350 fps with 135 gr Noslers is just fine. Was my standard IPSC load for years when I didn't own a working Super. Killed a deer with the load at 65 yds. Instantaneous death.

If I need more than that ... I use a 41 or 44 Mag.

[WilliamDahl]

I definitely load hotter than normal 40 S&W. In one experimental run I achieved 1580 fps with 135 gr Nosler HPs. Brass and primers were fine.

748 ft-lbs... Quite respectable...

[bobthenailer]

If trying to duplicate 10mm velocties in a 40 S&W case at normal COL the case will have a smaller case capacity and would be beyond max safe pressure for the 40 S&W case to acheive 10mm velocties.
IMO bite the bullet & buy some 10mm brass ! put up a post someone might have some to sell ?
Starline brass has it in stock $85.50 for 500 new 10mm brass

[KYCaster]

No...



YEAH! What he said!!!!

Section a couple of cases and take a look at how thick the brass is over the feed ramp.

10mm brass is cheaper than fingers.

Jerry

[mortre]

SAAMI pressure limits for the two are pretty close. It's the extra case length/powder capacity that makes the difference.

Similar to 9mm and 38 Super, the big difference is powder capacity. The 38 super will outstrip the 9mm by a good margin at the same pressure.

Sent from my DROID3 using Tapatalk 2

[Any Cal.]

Is this OAL independent of the nose profile of the bullet?


I have built two 1911 based 40 S&W pistols. Both have very high quality sides (Colt Delta Elite and Baer), and fully ramped Nowlin barrels. I load 40 S&W long and use 10mm magazines.

One is a comp gun and the other is not.

I definitely load hotter than normal 40 S&W. In one experimental run I achieved 1580 fps with 135 gr Nosler HPs. Brass and primers were fine. They left dents in T1 armor steel poppers. Came to the conclusion that such a load simply was not needed!

1350 fps with 135 gr Noslers is just fine. Was my standard IPSC load for years when I didn't own a working Super. Killed a deer with the load at 65 yds. Instantaneous death.

If I need more than that ... I use a 41 or 44 Mag.

What I was doing was basically like mstarling, loading to 10mm dimensions and charge weights using .40 brass. It allows more room for powder in the .40 case, since you aren't consuming so much space with the bullet. You are trying to duplicate a 10mm load exactly, but using a bit less brass around the body of the bullet. I will see if I can get a pic to illustrate, but remember, these are not going to be .40 spec, they won't fit in the mag or feed, they will require 10mm length mags and a 10mm chamber or a .40 chamber throated extra long. It is NOT just a matter of upping the powder charge in a .40, that is a good way to blow a gun up...

[Any Cal.]

Alright, here is a pic to illustrate...

http://img256.imageshack.us/img256/930/img0659pf.jpg

Same powder charge, same bullet, same OAL, just a different case length. The case will no longer headspace on the casemouth, but on the extractor. On some guns, doing this is a BAD idea. On the Glock, seems to be fine. The case on the .40 is basically identical to the 10mm case with the exception of length, some claim stronger due to the smaller primer.

-Edit- Those boolits are puuuuurrrty 'cause :castmine: [smilie=w: Unless those were some I had laying around, in which case someone else cast mine... :D

[aarolar]

I explained that in post #3... 10mm brass is a bit scarce around here and it would be nice if you could just load rather hot .40SW in its place.

If we weren't the type of people who wondered "what if", we would just be buying commercial ammo, right? :)

They sell it at Midway USA everyday or you could post a WTB add in the S&S and Im sure one of the upstanding members here would be more than happy to supply you with some for a more than reasonable price. Heck if I had any I would send some for free just to save your fingers and hands. :?

[subsonic]

This is bad because:

If you are shooting it in a .40 chamber, the throat is too short.
If you are shooting it in a 10mm chamber, you are launching the boolit crooked when headspacing on the rim. My G20 will pierce primers when shooting .40s out of the 10mm barrel.
If you are expecting the same case capacity at the same OAL, you are mistaken. The same OAL will not chamber in a .40 chamber unless you pay to have a long throat cut (probably more money than 500 10mm brass). Also, the .40 brass is different in the web (see above).
I've seen people do this. It's a seriously bad idea. But if you want to do it, they are your fingers. Just don't stand near me when you're shooting.

[WilliamDahl]

Alright, here is a pic to illustrate...

Same powder charge, same bullet, same OAL, just a different case length. The case will no longer headspace on the casemouth, but on the extractor. On some guns, doing this is a BAD idea. On the Glock, seems to be fine. The case on the .40 is basically identical to the 10mm case with the exception of length, some claim stronger due to the smaller primer.


What is the length of that bullet? Assuming that the bullet is supported sufficiently in the brass so that it does not change in length in the loaded round, the pressure should be the same. In both the 40 and the 10mm in your example, the empty space between the top of the powder and the bottom of the bullet would be the same, thus the same pressure. The only difference is that the 10mm would have a bit more brass supporting it.

[Adam10mm]

The weak point in the 10mm case is the primer pocket. The .40 case is stronger at this point because its small primer size allows for more material around the pocket, thus strengthening it.

Proof loads are loaded to 1.5 times the SAAMI MAP. In the 10mm, this means 56,250psi. In the .40, this means 52,500psi. These are 5 rounds at this pressure to proof the barrel. It's not a steady diet.

As an ardent proponent of the 10mm and glorified hater of the .40, it's in your best interest to load the cartridge to the chamber of the barrel. Don't be juvenile and think you can push anything beyond its limit. It's been done and the failures point right back to doing things within certain criteria.

If you have a 10mm, then you got into it knowing about the brass economy. This is no surprise. Once you step out of the 9/40/45/38/357Mag comfort zone, your wallet is going to take a hit. Performance costs money. You can't buy a Lambourgini for the price of a Honda Civic.

In short, don't be stupid. Load safe ammunition above all else.

[sargenv]

If using the long loaded 40 in a 610, you should not have any headspace issue since it headspaces on the moon clip. I've used 40's for years loaded way longer than any 40 would chamber in a bottom feeder or even in a 1911 pattern pistol. I've pushed 40 cal 193 HP's to about 1175 fps in my 6.5" gun and I think with a different powder could have pushed them a bit faster.

[Any Cal.]

What is the length of that bullet? Assuming that the bullet is supported sufficiently in the brass so that it does not change in length in the loaded round, the pressure should be the same. In both the 40 and the 10mm in your example, the empty space between the top of the powder and the bottom of the bullet would be the same, thus the same pressure. The only difference is that the 10mm would have a bit more brass supporting it.

Bullet length is .715ish? Anyway, you've got the general idea. I don't think I would do it with a short bullet, but the longer ones do fine. I've got around 400 rds through the barrel in this configuration with no issues I can attribute to the brass, but as you can see, some feel it is a really bad idea. If you lose 5 pieces of brass each time you shoot, that is less than $1 per box; you have to decide if it is safe enough to be worth it. I have had no issues, and don't see how there could be any, but obviously others are worried about you, so take any of this for what you paid for it.

Incidentally, there is less bullet jump doing it this way than there is in shooting a .38 in a .357 chamber, and you are loading the brass to a pressure similar to what it was intended to run. Some would say that there is less chance of the ejector hitting the primer of a loaded round on extraction, and you are using brass that is stronger in the web, like freakshow mentions above.(freakshow has forgotten more than I will ever know about 10mm, but I am not telling you to exceed the pressure limit of the brass...:-) )

I love the 10mm, even if I shoot it w/ homegrown bullets, dirty .40 cases, and run it through a Tupperware gun...:redneck:

[mold maker]

There is a reason the .40 S&W is nick named .40 short and week. Unless the replacement barrell was specificly made for this purpose, it was made to .40 specs. That means .40 preasures, not 10mm.
Not saying it can't be done within the safety margin, but very unwise wise. I'd never take a chance with my weapon or my hands to save the price of brass. You've already spent way more than the price of extra 10mm brass in the .40 setup.
I too have buckets of free .40 brass, but my Delta Elite will always be fed only10mm brass.

[btroj]

Why take a chance and damage anything? Of you need more velocity, use the 10mm barrel. If that isn't enough then buy a bigger gun.

I don't see a point in attempting to hot rod a cartridge. As small as a 40 SW case is evens tiny increase in seating depth or powder charge can rapidly I case pressure.

Seems pretty silly to me.

[WilliamDahl]

As an engineer, I guess I just like to experiment... :)

Originally, I was just thinking of taking a .40SW barrel and loading .40SW brass to 10mm pressures and velocities, but it seems that with a long enough bullet, you could even get away with firing the .40SW round in the 10mm barrel. That's an interesting data point... Now, if you wanted a lighter bullet, it probably wouldn't be long enough unless you made it into a hollow base bullet. Maybe a bit too much trouble, but it might make for some more interesting data points.

I was up at a local sporting goods store last night and looked at the selection of 10mm and .40SW rounds that they were selling and there was only 2 choices in 10mm and easily a dozen different choices in .40SW. Looking at the Federal choice, I only saw a 30 fps difference between the .40SW and 10mm (1000 fps vs 1030 fps with the 180 gr Vital Shock round) -- 400 vs 424 ft-lbs. Pretty mediocre compared to what the Buffalo Bore 180 gr rounds can in 10mm.

Finally got in touch with the guy at the local range that collects the spent brass and he has some unprocessed 10mm for $31 per 1000 (plus tax, of course). So, I'm not going to be pressed for brass, but it still would be interesting to experiment a bit and see how far the .40SW could be pushed in a frame built for 10mm pressures.

[Adam10mm]

$31 per K for 10mm brass is an outstanding price. Generally it sells for $50-70 per K on forums.

[Any Cal.]

That is a good price for brass, I pay roughly that for forty brass. You won't get much by running at ten mil pressures in forty brass, they are basically the same. It is the case capacity that gives you the edge.

If you want to get into full-retard loading, look for posts by Clark in a few forums. He compresses powder charges multiple times and does all kinds of things that are kind of out there to see what happens. If I was trying to make a forty into a rifle cal or something, that is where I would start. He is really hard on guns but he still has enough fingers to type...:)

[WilliamDahl]

$31 per K for 10mm brass is an outstanding price. Generally it sells for $50-70 per K on forums.

I have to drive probably 70-80 miles total (there and back) to go get them, but I can use it as an excuse to either take my Harley out for a ride or maybe as an excuse to go to some restaurant over on that side of town.

[WilliamDahl]

When I drove over there today to pick up the brass, they said that it was $35 per thousand instead of $31 for the unprocessed brass. After driving that far through rush hour traffic on a motorcycle and having determined that I REALLY should have waited until later in the evening for the trip (both from a traffic standpoint and a heatstroke standpoint), I decided it was still a good deal, so I ended up paying $75.78 for 2K rounds of 10mm. They were nice enough to give me two heavyweight zip-lock type bags so that I could put one in each of my saddlebags for balance. Of course, as luck would have it, one of the bags ripped on the saddlebag lock mechanism as I was pulling it out once I got home and brass went everywhere... :(

[thegreatdane]

I know folks run equivalent 10mm loads in LONG LOADED 40 brass. This is only possible by using 10mm data and 10mm lengths in a barrel which has been long throated and can accommodate longer 40 loads. I believe All Cal.'s picture summed it up.

.40 loaded to 10mm length and fired in a throated barrel= yes. 40 lengths in a 40 barrel = no!

Sent from my SPH-D710 using Tapatalk 2

[MasS&W]

.40 S&W actually has a much higher Pmax than 10mm... by around 4K. I'm not sure I would risk that.

[softpoint]

What greatdane said. We have done it, the loaded aol needs to stay the same as it was with the 10mm. Not many .40 throats will accept that, the throat will have to be lengthened. I have shot quite a few .40 cal.factory rounds through my Glock 20, however, with the 10mm barrel in place. I'm not sure I could recommend it in a carry gun, because you are depending on the extractor rather than the chamber to maintain headspace.

[Adam10mm]

.40 S&W actually has a much higher Pmax than 10mm... by around 4K. I'm not sure I would risk that.
Pmax as in maximum pressure? 10mm is 37,500psi. .40 S&W is 35,000psi. The 10mm's maximum pressure is only 2,500 psi more than the .40 S&Ws.

[Von Dingo]

A few years ago, I talked to a gentleman who had an STI race gun in .40 S&W, that used 10MM mags. The throat was cut long, so that slugs could be seated outside the case as shown by Any Cal., and operate at 10MM pressures, using cheap and easy to find .40 brass. I looked for some information on this, as I hope to get one going too, but information was not to be found.

[dixondave]

It is never a problem to load a .40 S&W with 10mm load data as long as the OAL is 1.25" or greater. The problem is getting the gun to feed them. Most 1911 chambered in .40 S&W will feed these long loaded rounds as long as they are jacketed bullets and not oversized cast boolits. Just make sure you have enough leade. You may have problems if any bearing surface of an "oversized" cast boolit extends past the case mouth.

[WilliamDahl]

Once I finish getting my reloading bench back together, I think I'll give the .40SW brass loaded long a try (even though I have 1000 pieces of 10mm brass). It would be nice to know that I have that option. I'll try it with 5.5gr of Red Dot and a 175gr Lee cast bullet.

[Oreo]

Loading .40sw brass to 10mm oal is fine as long as you don't get bullet set-back.

I wouldn't load .40sw brass beyond .40sw pressure though, regardless of OAL. What this means is the extra case capacity of using 10mm OAL will allow for more powder and a faster MV, but the max load (max powder charge) will be a little less then true 10mm max. The max load this way ain't book data however, it's guestimation and trial-error. Be careful and don't push your luck.

That said, I'm going to design and have Miha make a group buy mold specifically for this purpose, after my WFN group buy closes. Keep an eye out if you're interested.

[WilliamDahl]

Loading .40sw brass to 10mm oal is fine as long as you don't get bullet set-back.

I wouldn't load .40sw brass beyond .40sw pressure though, regardless of OAL. What this means is the extra case capacity of using 10mm OAL will allow for more powder and a faster MV, but the max load (max powder charge) will be a little less then true 10mm max. The max load this way ain't book data however, it's guestimation and trial-error. Be careful and don't push your luck.

That said, I'm going to design and have Miha make a group buy mold specifically for this purpose, after my WFN group buy closes. Keep an eye out if you're interested.

I spent this evening getting my reloading table back together. Loaded up some 10mm brass with 5.5gr of Red Dot and some .40SW brass to 10mm OAL with the same amount of Red Dot. I believe that they will result in the same pressure since the distance between the bottom of the cartridge and the bottom of the bullet is the same. It really looks strange having that much lead sticking out of a .40SW cartridge though. I don't expect the velocities to be identical though since the 10mm uses large primers whereas the .40SW uses small primers.

[subsonic]

Cut a 10mm off to exactly .40S&W length. Fill that cut 10mm case and a .40 S&W with water. Weigh them both. Report back.

[WilliamDahl]

Cut a 10mm off to exactly .40S&W length. Fill that cut 10mm case and a .40 S&W with water. Weigh them both. Report back.

WIth a smaller primer pocket, the .40SW should weigh slightly more, unless there is a noticeable difference in the thickness of the brass between the two of them.

[thegreatdane]

Cut a 10mm off to exactly .40S&W length. Fill that cut 10mm case and a .40 S&W with water. Weigh them both. Report back.

subsonic, what are you getting at? I can't perform the experiment at the moment. What should we expect?

[WilliamDahl]

subsonic, what are you getting at? I can't perform the experiment at the moment.

OK... I tried the experiment multiple times...

Took new 10mm and .40SW pieces of brass... Cut them down to the same length... Filled them with water... Weighed the 10mm one... Weighed the .40SW one... The 10mm one weighed more...

Tried it again... Filled both up with water... Weighed the .40SW one... Weighed the 10mm one... The .40SW one weighed more...

Tried this a few more times and the one that I weigh first always weighs more...


What should we expect?

A wet table and scale...

[subsonic]

I guess I should have been more clear that you are trying to find the water capacity by weighing the empty case and the amount of water it holds by subtraction.

You have to be careful to fill only to the top edge and have the cases the same length. The meniscus (water that will sit on top from surface tension) can skew your results.

I beleive you will find that even at the same length, there is a difference in case capacity that you need to account for.

[Oreo]

Yea, but I wouldn't get too worked up about it. I mean, there's that much difference (case capacity) between different bullets of the same weight.

The fact is this reloading stuff is not an exact science most of the time. Hence, the concept we're discussing works and gives a performance advantage over standard .40sw at a price discount over standard 10mm, but its not a cartridge one should be pushing any limits with. If one keeps things reasonable any difference between the 10mmA and 40sw case heads or brass thickness is negligible, IMO.

[subsonic]

I think this thread will come to an abrupt end when you seat a boolit to 10mm OAL in your .40 case and try to chamber it in your .40.

And I will repeat, DO NOT USE .40 BRASS IN A 10MM CHAMBER!

[Von Dingo]

William Dahl,

Does the .40 chamber have a long leade?

[Any Cal.]

And I will repeat, DO NOT USE .40 BRASS IN A 10MM CHAMBER!

And I will repeat, that has been fine for 6-700 rds for me in a G20 I was playing with.[smilie=l:

Oh, wait... IT HAS BEEN FINE FOR 6-700RDS IN A G20 I WAS PLAYING WITH.[smilie=l:

[Oreo]

These are not for use in a .40sw. They're for use in a 10mm with long-throat 40sw conversion barrel. (Not a standard 40sw barrel.)

[WilliamDahl]

These are not for use in a .40sw. They're for use in a 10mm with long-throat 40sw conversion barrel. (Not a standard 40sw barrel.)

As far as I know, my G29 has the stock 10mm barrel. I *guess* you could consider a 10mm barrel as a long-throat .40SW barrel... :)

[WilliamDahl]

William Dahl,

Does the .40 chamber have a long leade?

It's not a .40SW chamber, it's a 10mm chamber... It's a G29 which only comes in 10mm as far as I know...

[WilliamDahl]

I think this thread will come to an abrupt end when you seat a boolit to 10mm OAL in your .40 case and try to chamber it in your .40.

And I will repeat, DO NOT USE .40 BRASS IN A 10MM CHAMBER!

I doubt that these long ".40s" would even chamber in a .40SW gun. Hell, they might not even load in the magazine.

[Oreo]

It's not a .40SW chamber, it's a 10mm chamber... It's a G29 which only comes in 10mm as far as I know...
What you're doing may work but it's not the ideal kit.


I doubt that these long ".40s" would even chamber in a .40SW gun. Hell, they might not even load in the magazine.
They definitely would not fit in either gun or magazine.

[Von Dingo]

It's not a .40SW chamber, it's a 10mm chamber... It's a G29 which only comes in 10mm as far as I know...

It might work, someone loaded some 9X19 in my G29 and they fired. For accuracy and proper headspace, you might think about getting .40 barrel and getting the leade cut longer.

Keep us posted

[WilliamDahl]

Just for the 'ell of it, I tried the 10mm ".40s" to see if they would load in a couple of .40Sw handguns that I have... As expected, they would not load in the magazine, BUT they would actually load in the chamber if I inserted them into the chamber manually. So, theoretically it would be *possible* to shoot one of these 10mm load .40s in a .40SW handgun, but only as a single shot. From a practical matter, it would probably be a "single shot" in more ways than one... :) They fit in the chamber of a 96FS without a problem, but a "real" 10mm round would not. Just an interesting data point, I guess...