Shot first .40 S&W reloads... Need advice...

[Idaho45guy]

Was not an ideal range session since I drove 15 miles in a blizzard to get to my dad's range, then realized I had forgot a barrel that I was going to test.

Cast my own 175gr Lee boolits, checked everything out, made sure the OAL was good, crimp was good, used 6 grains of Unique in one load and 4.5 grains of Tite Group in the other.

Pistol was my S&W M&P40 compact. I had read where other folks had bought a factory M&P40 fullsize barrel and dropped it in for an extra 3/4" of barrel and increased velocity. Sounded like a neat idea, so that's what I did. This was the first time shooting the pistol with the longer barrel dropped in, so I brought some FMJ plinking rounds to break it in. I also intended to bring the stock barrel with me which gives me incredibly tight 1.5" groups at 25yds. But, I left it sitting on the kitchen counter...

Got to the range and loaded up a magazine of the plinking rounds and fired away. Barrel locked up. Tapped it forward and fired again. Locked up again. Disassembled and ran break-free on everything. Started running good and I continued shooting until it had broken in. Fired some groups and was not impressed; 3" or so.

Then I loaded up five rounds of the 6.0 grains of Unique. Cycled the slide and it went into battery as normal. Fired the first shot and hit close to where I was aiming, but the slide didn't return to battery. It was maybe 1/8th of an inch to the rear. Tapped on the back of the slide and it went forward. Fired the next four rounds and each one I had to hit the back of the slide to get it to go forward. And the group was awful; didn't even bother measuring it...

187071

Then I tried the 4.5 grains of Tite Group loads and had the exact same results with the slide not going all the way into battery and awful group sizes...

187072

Since I also got poor accuracy from the factory loads, I'm chalking that up to the failed barrel experiment. But the factory loads had no issues with going into battery, so that is something going wrong with my reloads.

What should I be checking first? My OAL is the proper 1.115 for a 175gr cast boolit...

[plainsman456]

Be sure to do the plunk test with your loaded ammo.

Might be need to be seated a tad deeper.

[rodsvet]

Sounds like the brass was previously fired in a Glock or other poorly supported chamber. I had that problem and bought a Redding bulge buster and de-bulge before sizing and all my rounds plunk now. Don't roll crimp and check your OAL. Good luck with your new barrel! Rod

[reddog81]

No mention of OAL in the post but that is probably the culprit. Your bullets are getting lodged into the rifling. Smacking the slide is fully chambering the round and seating the bullet into the lands. Not an ideal situation for accuracy.

even if you did the plunk test at home you can run into this problem at the range once the gun is dirty or the barrel starts to lead. Bullets that previously can now cause problems.

Sometimes un-sized bullets or too large bullets can cause this problem if you have a tight throat but I'd guess slightly too long OAL.

[Idaho45guy]

Be sure to do the plunk test with your loaded ammo.

Might be need to be seated a tad deeper.

Doh! Rookie mistake... Checked and the factory stuff fully seats but the reloads do not. It seems that the cast boolits are not going to work with my chamber. They are at the perfect OAL and seating them in another 1/16th of an inch is going to increase pressures??

Do I need to go with another design that doesn't have that straight-walled rim for the first 1/16th of an inch?

187079

187080

187081

[Idaho45guy]

Sounds like the brass was previously fired in a Glock or other poorly supported chamber. I had that problem and bought a Redding bulge buster and de-bulge before sizing and all my rounds plunk now. Don't roll crimp and check your OAL. Good luck with your new barrel! Rod

Brand new unfired Starline brass...

[gnostic]

Sounds like a job for 'the bulge buster.' Measure your loaded round in the web area, it may be too large. Can you see where the sizing die stops on a sized case?

[Dusty Bannister]

Did you powder coat those bullets? What is the groove diameter and what is the bullet diameter? When powder coated, the diameter of the bullet is larger as is the nose of the bullet, so a plain lead bullet will still be OK, but powder coated will engage the lands a little sooner. If you know how to use the dowel or cleaning rod method to determine the cartridge OAL, give that a try and see what the cartridge OAL actually is for that bullet in that barrel. The published cartridge OAL is for their bullet in their barrel. If you do need to seat a little deeper, start with the suggested starting load and slowly work up until you get reliable cycling or pressure signs, or the max charge.

If the cartridge is not fully and easily chambering, it will shoot high because it is not going completely into battery. See if the firing pin is centered in the primer cup.

New unfired Starline? Did you full length size when starting?

[MT Gianni]

I have a Kahr that has to have bullets sized .401 and a Smith and Walther that prefers .402. I suspect you may be a little too wide to seat in the barrels throat. I would try an impact slug and set oal and diameter off of that. Both my guns prefer power pistol by a wide margin.

[Idaho45guy]

Boolits are .403 and it slugged at .401...

Easy fix for future boolits...

[308Jeff]

The couple of 40's I've reloaded for have been very finicky about what they like.

What's the weight of that cast bullet? I'd be a little nervous about seating them any deeper. 40 pressures go up REAL quick. Just looked at my load log and all of my 40's have been seated between 1.125 and 1.135.

It looks like you've got a pretty healthy crimp on those bullets. Enough so that if bullets are not oversized (which you've already said they're .401), I'm inclined to think that you are getting hung up on that bullet shoulder, and it's not a conducive design for your barrel.

I could be wrong. I learn something new on this site every day.

[DougGuy]

With that much shoulder sitting proud of the case, it would help IMMENSELY if it had enough freebore to plunk those.. Your barrel would benefit greatly from being throated, this is what throating does, allows you to load to whatever COA you want to, without the boolit interfering in the throat because the throat is too tight when it goes into battery.

ALSO.. And I will mention this, the 40 is already a fairly high pressure round, and if any of your boolits suffer setback into the case when you "tap the slide home" you could be in for a KB and it has happened in exactly this scenario. Boolit gets pushed back into the case, pressure goes through the ROOF, blows the case out and then ignites the top 2-3 rds in the mag and blows it all out the bottom if you are lucky, out the sides and into the palms of your hands if you are not. This ctg and the 9mm are both critical that no setback occurs, in the 9mm, if it is loaded to the max of 35kpsi, just .010" worth of setback can run pressures upwards of 60kpsi.. Not fun.

Pic of Glock 19 barrel after throating, this might be a KKM or LW barrel it is not the factory Glock barrel:

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/Glock%20Throating/Glock19-640_zpsv5rzqop5.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/Glock%20Throating/Glock19-640_zpsv5rzqop5.jpg.html)

These are LW barrels, on the left is a 10mm barrel after throating, on the right is a 40 S&W barrel for the same pistol that the owner wanted throated long enough that he can load to 10mm COA and use 40 brass:

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)

Next is a Kahr P-45 barrel with polygonal rifling. Kahr is notorious for tight barrels with zero throat, I carry a CW45 that would only chamber .451" and nothing else. It's fixed now too..

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/Kahr%20P45%20polygonal/DSC04932%20Custom_zpsx2zh6d8z.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/Kahr%20P45%20polygonal/DSC04932%20Custom_zpsx2zh6d8z.jpg.html)

I am sure these pics will give you a good idea of what works really well for cast in an autoloader, seating deeper than what load data calls for is just a poor workaround for the real problem, too tight a throat and either zero freebore or freebore slightly too small to function well with cast.

[Love Life]

Doh! Rookie mistake... Checked and the factory stuff fully seats but the reloads do not. It seems that the cast boolits are not going to work with my chamber. They are at the perfect OAL and seating them in another 1/16th of an inch is going to increase pressures??

Do I need to go with another design that doesn't have that straight-walled rim for the first 1/16th of an inch?



Two choices:
1) Seat deeper and do a full load work up
2) Get the barrel throated

I would choose option number 1.

[Idaho45guy]

Awesome advice and knowledge here as always... Thanks guys!

[Idaho45guy]

Going to pull all of the boolits (only have 40 left) and salvage the cases and start from scratch with properly sized boolits this time. I'd hate to mess with my factory barrel since it gives me such awesome accuracy. Might try a different style of boolit mold as well. The new XDS arrives next week, so I'll have to see how tight it's chamber is as well and go from there...

[KYCaster]

So you install a new barrel and the gun malfunctions. You get it to function, but accuracy is lousy with factory ammo.

You try your reloads, gun malfunctions and accuracy is lousy.....

I'd start by looking at the barrel fit. It may not be a true "drop in"....not all that unusual.

Next, I'd take DougGuy's advice and get the barrel properly throated.

Next, I'd take Love Life's advice and determine the proper OAL for your cast boolit, start low and work up a load that works.

Or, do the last two steps in reverse order...load your boolit like you want it then send the barrel (with some dummy rounds) to DougGuy and have the throat reamed to fit your load.

Jerry

[Chihuahua Floyd]

My Kahr likes my Lee 175g TC seated just a tad deeper than a factory ammo OAL. Don't have data as I am out of town, but only had to seat 0.01 deeper.

[runfiverun]

If you have any full diameter sticking out of the case that's probably what's hitting.
seat deeper, drop the load.

I'm running a full grain lower with the T-group in the SIL's 40 using a 180gr boolit.
I had to work the oal down to 100% chambering then work the load up to 100% function.

[Love Life]

If you have any full diameter sticking out of the case that's probably what's hitting.
seat deeper, drop the load.

I'm running a full grain lower with the T-group in the SIL's 40 using a 180gr boolit.
I had to work the oal down to 100% chambering then work the load up to 100% function.

Perzactly, lol.

[Bzcraig]

Two choices:
1) Seat deeper and do a full load work up
2) Get the barrel throated

I would choose option number 1.


This...... Though I chose option 2 because I wanted to be able to try different boolits without having to do the full work up.....Lazy

[Doggonekid]

I agree with bzcraig I would pick option 2. It made a big difference with my Colt.

[reddog81]

I'd seat the bullet .01 or .02 deeper and drop down to 5.8 grains unique.

[Boolseye]

187123To the OP: I shoot the same boolit, same round, same gun. I seat to 1.110, have to. no issues, shoots great. I'm not surprised those rounds aren't chambering with that much boolit showing.
Hire Dougguy if you want to load them long, otherwise drop your charges and seat them deeper. Use the Lee FCD if you want fail safe chambering.

[Idaho45guy]

187123To the OP: I shoot the same boolit, same round, same gun. I seat to 1.110, have to. no issues, shoots great. I'm not surprised those rounds aren't chambering with that much boolit showing.
Hire Dougguy if you want to load them long, otherwise drop your charges and seat them deeper. Use the Lee FCD if you want fail safe chambering.

What powder are you using and how much? The Unique loads were much softer shooting that the Tite Group loads, but Tite Group seemed to have a little better affinity for tighter groups, oddly enough...

[Plate plinker]

Boolits are .403 and it slugged at .401...

Easy fix for future boolits...
Start with this.

[dverna]

Just a comment on accuracy. This is not a target gun. If you are getting 3" groups at 25 yards that is about what the gun will do. Your 1.5" groups with the other barrel may be a fluke or you just got lucky with that barrel.

The others have covered the feeding/cycling issues...all good advice.

Don Verna

[DerekP Houston]

My Kahr likes my Lee 175g TC seated just a tad deeper than a factory ammo OAL. Don't have data as I am out of town, but only had to seat 0.01 deeper.

I have a S&W MP 40, I had to seat mine a little deeper as well for it to function and feed better. I switched to a NOE RN mold design and haven't had any issues since then.

[Boolseye]

What powder are you using and how much?
My standard load has been 4.5 gr. 231. Very similar burn speed to Bullseye, slightly slower.

[scattershot]

If I understand this correctly, you put a full size barrel in a compact pistol. The barrels are not the same diameter for their full length, having a raised portion or boss, for want of a better term at the muzzle end. That extra smaller diameter barrel hanging out the end of the slide will not seat correctly, and I suspect that is the cause of your accuracy problems.

The ammo not seating properly is another problem, which has been addressed already.


Good luck!

[dondiego]

How did you arrive at the "perfect" OAL? If it doesn't work in your barrel, it is not perfect for it.

[runfiverun]

I was thinking the same thing.
a close barrel to bushing fit at the muzzle is a necessity for accuracy in a pistol.

[Love Life]

Does the M&P have a bushing? I was wondering if springing might be an issue with the longer, unfitted barrel.

[scattershot]

No bushing, but the raised portion of the barrel is what locks up the barrel at the front.

[DougGuy]

I'm not sure all of the M&P pistols have a "series 70" hump at the end of the barrel. Best I can remember the short ones I have seen here have been straight. But yes if you can wiggle the barrel any at all in the end of the slide when it's in battery, that bit of slop right there will add about 500% to the size of your groups..

[scattershot]

My 40c and the 9mm conversion barrel I have for it both have the larger diameter ring at the front. My full size 40 had it, too, but I no longer have the pistol to check.

[LAKEMASTER]

im really glad i found this topic. im possibly doing a plinking run of 500 rounds this friday for my family thats coming up to shoot. i was kinda unclear about COAL and the starting load.

[Cherokee]

Did not see anyone mention it so: Check your taper crimp on the loaded round, make sure you have completely removed the bell you put on the case mouth to seat the bullet. Compare the tapered measurement to the factory rounds...it should be the same or slightly smaller.

[popper]

OAL is determined by your barrel & boolit. Then work up a load. Book values are test numbers.

[runfiverun]

you have to have the COAL set to feed and to chamber.
that is your first priority, a gun that don't work is worthless.
after that you need to judge your starting load from the available case capacity left.
judge the room left by where the base of your boolit sits compared to tested and known data.

[rsrocket1]

My M&P 40 slugged at 0.4005" on the grooves so a bullet sized to 0.401" works well. My Lee 401-175-TC 6 banger drops at 0.402" and after powder coating, the bullets are at 0.404"-0.405". I size them down to 0.401" and seat them to 1.10" which puts the cone right at the rim of the case. I used to seat them to 1.135" for max velocity and lowest pressures, but now I regularly seat them to 1.10" and sometimes I don't even size them, I just put a slight taper crimp to aid in feeding and I do plunk test every round. I originally used the M&P 40 barrel, but for a few bucks, I got a case gauge which is sized to minimum SAAMI specs and it's a little more convenient.

http://i270.photobucket.com/albums/jj96/rsrocket1/Shoot/Powder%20Coating/40PC_seated_zpsm4jmqucr.jpg

The Smith and Wesson M&P 40, 9 and Shields tend to have the tightest chambers and throats around.

I don't know where you got the idea to put a standard barrel on a Shield. That sort of defeats the purpose of a small concealable gun. You are aware that your MV and recoil will increase accordingly and with the decreased weight of the Shield, the recoil with a 4.25" barrel will be considerably higher than with a Standard M&P 40. I love my M&P 40 along with the 9mm barrel but I got a Shield in 9mm and am glad I did.

[308Jeff]

For those that are using the barrel plunk method to test fitment, are you also using a stand alone case gauge? Or just one or the other? I've always used a Lyman case gauge for my pistol rounds, and haven't had any feeding issues, but now I'm wondering if I should be doing both?

[rosewood]

I use the Lee 175 grain mold and I powder coat it with Smoke's clear. Come out great and are right at 180 grains. Sized at .401. I tested the OAL by taking out the barrels on my 2 most fired guns and made sure the completed boolit would "plunk". Using 6.3grains of Power Pistol (0.57 auto disk), I am getting dead on 1000 FPS out of a 4.5" barrel Sigma 40 and it is incredibly accurate. It also shot well out of the Sig P229. I think I had tried a couple of other powders and power pistol was the most accurate. I found the powder coating dictates seating deeper than just lubing the boolits as it adds enough diameter to hit rifling sooner. I have not had any feeding issues since I adjust the OAL by the "plunk" test.

Rosewood

[rsrocket1]

For those that are using the barrel plunk method to test fitment, are you also using a stand alone case gauge? Or just one or the other? I've always used a Lyman case gauge for my pistol rounds, and haven't had any feeding issues, but now I'm wondering if I should be doing both?

Typical commercial case gauges are minimum SAAMI spec dimensions meaning if they pass the plunk test in the case gauge, they will fit just about any barrel unless it's out of spec on the small/short side.

I used to use my barrels simply because I didn't want to pay shipping etc for a case gauge but since my local gun store had some in stock, I simply bought a 9 and 40 gauge.

If you use your gun's barrel, you know it will work in your gun. If you use a case gauge, the finished cartridges ought to work in any gun.

[308Jeff]

Typical commercial case gauges are minimum SAAMI spec dimensions meaning if they pass the plunk test in the case gauge, they will fit just about any barrel unless it's out of spec on the small/short side.

I used to use my barrels simply because I didn't want to pay shipping etc for a case gauge but since my local gun store had some in stock, I simply bought a 9 and 40 gauge.

If you use your gun's barrel, you know it will work in your gun. If you use a case gauge, the finished cartridges ought to work in any gun.

That was my understanding as well. Thank you.

[bayjoe]

Maybe try sized bullets without the powder coat. That is what my Para likes. And I shoot 4.8grains of 231

[Idaho45guy]

Started from scratch using 175gr cast boolits to .401 and recommended OAL of 1.115. Loaded with 4.6gr of TiteGroup. tried the plunk test with both an M&P barrel and the one from my new XDS.

Neither would plunk. Compared my rounds to a Hornady Critical Defense 165gr with an OAL of 1.115 and it plunks perfectly. Just kept cranking down the die until the reloads would plunk and they finally fit perfect at an OAL of 1.065. Obviously way too short and will likely cause pressure issues, IIRC.

Can I simply not shoot these boolits in my pistols without getting the throats modified?

Not sure what else I can do without having work done on the barrels, which I don't want to do since both pistols are extremely accurate as they are.

If I can't shoot the 175gr cast boolits, then that will really suck. Was the whole point of casting for the .40 was to have some serious hard-hitting rounds for woods carry.

Any ideas?

188880

188881

[Idaho45guy]

I'm thinking of spending some more cash on the RCBS 180gr boolit mold. It seems to have a better profile without that "lip" that is causing me issues...

188882

[Wayne Smith]

I had a similar problem with my .45s. I have a Para that I loaded for and cast for and it shot everything. Got a Kimber Light Commander and had exactly the same problem. Took both guns to DougGuy and he throated them both the same. Now they both eat the same ammo without a problem. For me, fixing the gun was the solution, since they were not the same to begin with.

[Tackleberry41]

Try another bullet, see if it works. That longer nose may make the difference.

One thing to consider with OAL length is how deep the actual base of the bullet is in the case. Most cast bullets tend to be shorter than jacketed of equal weight. So that short OAL length may not mean its reducing the case capacity and raising the pressure. Lee manuals for example will say '175gr lead', okay but no specifics as to the bullet. I have a 180gr mold, but its a 200gr w a HP pin so really is as long as the 200gr. You may find that bullet seated that deep really isnt that deep.

Stuff like this where theres no data for a specific bullet. I will use some min data, load to fit my gun, and run it over the chrony, compare to what it says in the book. Is it higher or lower than what the book says? A bit higher and your running hotter. Often they are slower, lower pressure, the case capacity is different than the test data. Usually due to the bullet length difference.

[DougGuy]

A lot of advice in this thread, some of it I might add by some very knowledgeable and experienced casters and/or handloaders suggesting to start with "guesswork" for lack of a more accurate term. Seat deeper, work up. I know it has been done, but fellas this is not really the right thing to do.

This comment may ruffle some feathers of some of our members, some who have posted in this thread, this is NOT my intention to do such. This is NOT why I am writing this reply.

A lot of testing and lab work went into producing this published and tested reloading data with the safety of guys like us in mind. *IF* it was a safe practice, it would be a widely accepted and published guideline telling where to start "guessing" and when to determine that one has reached the upper limits of pressure and safety.

*IF* you cannot seat your handloads to the PUBLISHED, tested, and proven data in the reloading manuals or the powder manufacturer's data, then something is WRONG and it ain't the ammo!

Consider a couple of things. First and most important is the pressures the 40 runs at. It is a high pressure cartridge very similar to the 9mm. The 9mm running at 35kpsi can see pressures spike easily to 60kpsi with as little as .010" boolit setback! Whether the shooter seats .010" deeper at the press, OR the boolit is seated deeper by ramming the feed ramp or by being crammed into the rifling because of a throat that is too tight, OR the shooter that "helps" the slide go into battery by bumping it. This can trigger a CATASTROPHIC FAILURE.

Ask me how I know this, because I blew up a 40 once, in a Para I had built, got very lucky and it only lit off the top 4-5 rounds, blew up the mag and dumped everything out the bottom. I was not injured in the event. It could have been a LOT worse!

9mm and 40, you have VERY LITTLE room for error, IF any. Manufacturers adhere to dimensions that accept factory jacketed ammo with safety as the NUMBER ONE priority. They DO NOT make any effort to acknowledge or provide for any level of safety or functionality of handloads not assembled by factory means using new components.

What if Speer or Federal or one of the other major players were sent a few million bullets .402" in diameter. Can you imagine the hoops they would have to jump through to use these bullets? They would have to reset EVERY piece of equipment in their whole line! New dies, new expanders, new seaters, new everything INCLUDING their tried and tested load data. They would have to start totally from scratch!

And then there would be thousands and thousands of complaints from consumers because the ammo would not chamber in their guns! There would be lawsuits in cases where shooters blew up their guns trying to force this ammo to work!

Sheesh.. .402" is something that WE do everyday, without issue. There are ONLY 3 ways to fit a boolit into a barrel. Only TWO of the three are safe and fall within published data, that is to size to fit the throat in the barrel and still be able to use published load data, OR simply have the barrel throated to chamber and function with your chosen boolit diameter, again assembled to published COA lengths with published and tested load data.

The third way is to use whatever diameter boolit one chooses to use, and keep compromising load data until you get it to work. This may seem to be a practical approach often used, but in the end it is nothing more than guesswork and this is NOT good.

If you want to use a certain style or size boolit, and it won't fit in the chamber? Have the barrel throated, stay on the SAFE side with your handloads. Throating a barrel reduces pressure, provides a gradual, tapered leade in to the rifling, greatly reduces or totally eliminates leading, and will generally cut groups by as much as 50%. Plus all of your molds will now work, no need to hunt out a specific mold as a workaround to the fact that the mold you like drops boolits that won't plunk. What's not to like about that?

[Idaho45guy]

Awesome stuff, Doug!

I'm not sold on the Lee mold I'm using and would have no problem going to the RCBS one I posted.

My concern with throating the barrel is whether or not factory ammo would still be as accurate in it. Right now, I can shoot the finest self-defense ammo with the latest bullet technology and it is very, very accurate. If I throat the barrel so my 175gr hard cast loads will work, will then it be less accurate with conventional 165gr commercial loads?

[DougGuy]

It has not been my experience that factory j words are less accurate after throating. As mentioned earlier, the 40 is a high pressure cartridge and good defensive ammo is fairly powerful, so there is no shortage of pressure. J words are usually made with a soft lead swaged core inside a guilding metal jacket, these will very easily swage into the freebore when fired, providing a good seal and an excellent fitment in the throat. That keeps them accurate.

I would not be totally surprised if groups got even better with j words after throating. They do with cast.

Edit: I like that RCBS RF design a lot better than a TC design for the reason that it has a longer bearing surface on the sides of it, which when seated into the throat, provides exceptional accuracy simply because the throat holds the boolit concentric to the bore where you lose this when you seat deeper in the case. This would be a good boolit after throating.

[fredj338]

Going to pull all of the boolits (only have 40 left) and salvage the cases and start from scratch with properly sized boolits this time. I'd hate to mess with my factory barrel since it gives me such awesome accuracy. Might try a different style of boolit mold as well. The new XDS arrives next week, so I'll have to see how tight it's chamber is as well and go from there...
A valuable lesson here. When doing load dev with new bullets or powder, just load 5, you'll have less to pull if it goes wrong.

[fredj338]

A lot of testing and lab work went into producing this published and tested reloading data with the safety of guys like us in mind. *IF* it was a safe practice, it would be a widely accepted and published guideline telling where to start "guessing" and when to determine that one has reached the upper limits of pressure and safety.

*IF* you cannot seat your handloads to the PUBLISHED, tested, and proven data in the reloading manuals or the powder manufacturer's data, then something is WRONG and it ain't the ammo!

Consider a couple of things. First and most important is the pressures the 40 runs at. It is a high pressure cartridge very similar to the 9mm. The 9mm running at 35kpsi can see pressures spike easily to 60kpsi with as little as .010" boolit setback! Whether the shooter seats .010" deeper at the press, OR the boolit is seated deeper by ramming the feed ramp or by being crammed into the rifling because of a throat that is too tight, OR the shooter that "helps" the slide go into battery by bumping it. This can trigger a CATASTROPHIC FAILURE.

?

This is oft repeated but totally out of context. OAL matters, but matters a lot less if your loads are below midrange. The doubling of pressures can happen, but not with every powder at every data point. That is just Speer doing a CYA. At max, everything matters though, even a primer or brass swap. Since virtually none of us loading cast bullets use exact data, we are always off the book to a certain extent. So yes, you can seat deeper & work up, especially if midrange or below.

[fredj338]

Awesome stuff, Doug!

I'm not sold on the Lee mold I'm using and would have no problem going to the RCBS one I posted.

My concern with throating the barrel is whether or not factory ammo would still be as accurate in it. Right now, I can shoot the finest self-defense ammo with the latest bullet technology and it is very, very accurate. If I throat the barrel so my 175gr hard cast loads will work, will then it be less accurate with conventional 165gr commercial loads?

DOne properly, you'll not likely notice much accuracy diff. In handguns, OAL is not as critical to accuracy, especially at the distance most handguns are shot, 50yds & under. My RSBH hunter will do sub 3" groups at 100yds & the bullet is waaaaay off the rifling.

[DougGuy]

This is oft repeated but totally out of context. OAL matters, but matters a lot less if your loads are below midrange. The doubling of pressures can happen, but not with every powder at every data point. That is just Speer doing a CYA. At max, everything matters though, even a primer or brass swap. Since virtually none of us loading cast bullets use exact data, we are always off the book to a certain extent. So yes, you can seat deeper & work up, especially if midrange or below.

Notice I referenced the 9mm at 35kpsi, a max loading. True the lower the pressure the less a variable like COA would matter. Close to the max, every little thing you do matters.

[Tackleberry41]

Few doing load development start at max, so there is room for error. I have seldom found where things end up on the short end with higher pressure. Its rare for me to even load to min OAL. I fit to my guns, which tends to be long. Some molds I have not sure how you would get them that short. I have a 158gr .360 NOE mold. Crimped in the groove its way longer than min in the book, seated to that spec they are to deep to crimp at all.

Nor do I make very many of something. But I dont have to drive to a range to test things, I can just step outside with a couple rounds, run them over my chrony and see how they do. Then step inside, make adjustments, fire a couple more. Usually only 3 at a time, gives a good indication of how they will do. If 3 shoot terrible, 5 wont be any better. Only after I know they work, will I make up 50.

Without a chrony its usually just guesswork. Cycles the gun, hits the target about all you will know.

[Idaho45guy]

Ordered the RCBS mold... We'll see how these work.

189231

[kevmc]

As already mentioned once, sounds to me like your crimp (roll or taper crimping?) is not removing all the flare.....
Measure at the case mouth of loaded round, I like .423" and/or resize a case, flare, crimp as normal without a bullet in place, "plunk test" this case. This will tell you if the problem is with the crimp or the bullet size/oal.
I load the Lee TC for my .40's, only FTC/load issue I've had was not enough crimp or roll crimp found on too many dies.
I use a Redding taper crimp die as the final step. seat/crimp in 2 steps..works for me

[MKN]

Idaho,
You can not "drop in" a longer barrel in the M+P, look at the muzzle of the barrel, it widens to meet with the slide when it is closed. The slide is designed for barrel length, they must match.
you locked up because the barrel was flopping around.
I don't mean to sound like an *******, but call yourself lucky and sell the longer barrel.
If you want search the S+W M+P forum, that will have info on why you can not change the barrel.
Matt

[Idaho45guy]

Tried some reloads today using the Hornady XTP HP 155gr bullets and 4.5 gr of Titegroup. Only did a quick five rounds at seven yards off-hand. Got likely the best 7yd 5-shot group of any defensive pistol I've shot. The XDS likes this recipe...

189658

[Moonie]

You may not like the Lee 175gr boolit but I competed in a BUG (BackUp Gun) match with my XD Subcompact mod.2 40 using powder coated 175 Lee boolits loaded fairly light. I had never competed at this range before, I was invited by a coworker and out of about 35 competitors I came in fifth. The boolit was accurate, cycled 100% and did a great job for me.

[Idaho45guy]

You may not like the Lee 175gr boolit but I competed in a BUG (BackUp Gun) match with my XD Subcompact mod.2 40 using powder coated 175 Lee boolits loaded fairly light. I had never competed at this range before, I was invited by a coworker and out of about 35 competitors I came in fifth. The boolit was accurate, cycled 100% and did a great job for me.

It's not that I don't like it. It just simply will not chamber in my pistols unless I seat it far deeper than what the specs call for. I can't afford to blow up a pistol experimenting with getting a boolit to work. I'd rather spend another $65 on a new mold.

[Moonie]

It's not that I don't like it. It just simply will not chamber in my pistols unless I seat it far deeper than what the specs call for. I can't afford to blow up a pistol experimenting with getting a boolit to work. I'd rather spend another $65 on a new mold.
Sorry, I should have mentioned that I seat mine so that just a hair of the full diameter is outside of the case, just deep enough to plunk in my only 40.

[gwpercle]

I usually deep seat and drop back the powder charge. If the deep seating increases pressure the reduced powder charge makes it all even out !

[Idaho45guy]

Finally got time to try out the new RCBS mold. Cranked out 100 or so rounds that looked very nice. Cooked up some rounds using 4.7grs of Titegroup and with the COL set at a perfect 1.125, they plunk perfectly in my barrel. So far so good.

Will have to wait until next week to see how my pistols like them, but, so far I'm pleased with the results.

190304

190305