40 S&W

[joeraf]

Is it necessary to crimp a 40 S&W load?

[smithra_66]

Originally Posted by joeraf

Is it necessary to crimp a 40 S&W load?

Usually not as long as you have a good friction fit on the case mouth. Just remove the flare.

[tlawler]

Originally Posted by joeraf

Is it necessary to crimp a 40 S&W load?

Just a light taper crimp works well for me, unless I’m shooting them in a revolver. Then I’ll use my Lee FCD and put a slightly tighter crimp on them to prevent bullet setback.

[Sevens]

Longer answer than you may be seeking...

It's my opinion that WAY back when all this started, the powers that be screwed up when they named this process crimping.

When you are building rimmed revolver rounds, your ammo is headspacing on that case rim and the normal process for handloads is the crimp the bullet in place. We use a roll crimp of some degree, and this crimp helps to keep the bullet in place under recoil so that it does not creep forward when the natural recoil of the revolver acts upon it. As a secondary benefit to high pressure large revolver rounds that use slower burning powder, a good heavy roll crimp also promotes a consistent burning of the powder, keeping the bullet from moving early simply from the primer blast while the slower burning powder builds it's pressure.* <---

None of this is the case for most typical semiauto pistol rounds, the .40 S&W absolutely included. We do not roll crimp and we aren't needing to do anything after/during bullet seating that is specifically meant or designed to grip that bullet in place. This is because generally speaking, semiauto pistol rounds headspace on the case mouth, it is the case mouth that sits itself on the forward edge of the chamber to put the cartridge in the spot it needs to be. Furthermore, pistol rounds do not tend to "jump" as they sometimes do in heavy revolver rounds under recoil.

The process we use during/after seating for semiauto pistol rounds is called a taper crimp and this process should have been named something different and NOT using the word "crimp." By using the word "crimp" it makes folks think that it's purpose is to help grip that bullet and keep it in place and that's false and misleading. The taper crimp when loading pistol rounds is the process of un-doing the flare part of the entire procedure, so that the loaded round fits nicely in the chamber AND can headspace with the ledge of the case mouth.

In a semiauto pistol round, the bullet is held in place by proper sizing of the case and by NOT applying too much case mouth flare, which naturally alters the case's grip on the bullet. And if you use too much taper crimp you will soon see with your own eyes that you actually lose grip on that bullet!

I believe the old guys a hundred years ago should have called the taper crimp something else. They should not have used the term "crimp." Some form of 'finishing' or 'finalizing' is more accurate than "crimp."

* <---
If you are loading .38 Special at 800 to 1000 fps with Bullseye or AA#2, the amount of crimp is likely to make no difference whatsoever in how the powder burns and how that burning affects the ultimate performance/velocity of the bullet. However, if you are loading .357 Magnum with a full load of AA#9 or H-110, using a light crimp here can and often will give you clearly erratic performance because these slower burning powders benefit and sometimes (especially H-110) simply demand a solid roll crimp to allow the pressure to build before the slug starts to move.

All of this happens at a rate so quickly that no human could sense the time difference but internal ballistics is extremely aware of it and the performance difference is obvious.

[Erocksmash]

Originally Posted by Sevens

Longer answer than you may be seeking...

It's my opinion that WAY back when all this started, the powers that be screwed up when they named this process crimping.

When you are building rimmed revolver rounds, your ammo is headspacing on that case rim and the normal process for handloads is the crimp the bullet in place. We use a roll crimp of some degree, and this crimp helps to keep the bullet in place under recoil so that it does not creep forward when the natural recoil of the revolver acts upon it. As a secondary benefit to high pressure large revolver rounds that use slower burning powder, a good heavy roll crimp also promotes a consistent burning of the powder, keeping the bullet from moving early simply from the primer blast while the slower burning powder builds it's pressure.* <---

None of this is the case for most typical semiauto pistol rounds, the .40 S&W absolutely included. We do not roll crimp and we aren't needing to do anything after/during bullet seating that is specifically meant or designed to grip that bullet in place. This is because generally speaking, semiauto pistol rounds headspace on the case mouth, it is the case mouth that sits itself on the forward edge of the chamber to put the cartridge in the spot it needs to be. Furthermore, pistol rounds do not tend to "jump" as they sometimes do in heavy revolver rounds under recoil.

The process we use during/after seating for semiauto pistol rounds is called a taper crimp and this process should have been named something different and NOT using the word "crimp." By using the word "crimp" it makes folks think that it's purpose is to help grip that bullet and keep it in place and that's false and misleading. The taper crimp when loading pistol rounds is the process of un-doing the flare part of the entire procedure, so that the loaded round fits nicely in the chamber AND can headspace with the ledge of the case mouth.

In a semiauto pistol round, the bullet is held in place by proper sizing of the case and by NOT applying too much case mouth flare, which naturally alters the case's grip on the bullet. And if you use too much taper crimp you will soon see with your own eyes that you actually lose grip on that bullet!

I believe the old guys a hundred years ago should have called the taper crimp something else. They should not have used the term "crimp." Some form of 'finishing' or 'finalizing' is more accurate than "crimp."

* <---
If you are loading .38 Special at 800 to 1000 fps with Bullseye or AA#2, the amount of crimp is likely to make no difference whatsoever in how the powder burns and how that burning affects the ultimate performance/velocity of the bullet. However, if you are loading .357 Magnum with a full load of AA#9 or H-110, using a light crimp here can and often will give you clearly erratic performance because these slower burning powders benefit and sometimes (especially H-110) simply demand a solid roll crimp to allow the pressure to build before the slug starts to move.

All of this happens at a rate so quickly that no human could sense the time difference but internal ballistics is extremely aware of it and the performance difference is obvious.

What he said !

[chief38]

A very slight crimp is all you need - remember an auto cartridge head spaces on the mouth, so it can't be too much of a taper.

[joeraf]

Thank you Sevens. A complete and thorough answer. Joe

[Nevada Ed]

The problem with a crimp on pistol ammo that sets its head space on the barrels cut chamber, is that, if too much, the case may bypass the chamber ridge set for proper head space, which could cause the case to be advanced too far forward for a firing pin strike on the primer.

Worst case, is that the round will fire and the bullet may be lodged into the lands and rifleing which will cause very high pressures.

If the case is too short, you might have the case being held to the correct length by the extractor, which is also not a good thing.

One reason wise loaders do the "Plunk test" to make sure the head space is correct for that weapon and load.

[BLUEDOT37]

While pistol cartridges traditionally don't have to worry about "jump crimp", in the revolver sense of the word, you still need to ensure that it doesn't get pushed deeper into the cartridge when the round is fed into the chamber because it's not held tightly enough.

And pistol cartridges largely use medium speed powders, which don't require the roll crimp a revolver cartridge needs to ensure good initial combustion from it's slower powder, so a taper crimp can suffice.

You typically have in excess of .020" difference between the chamber's mouth diameter (.424", +.004", SAAMI) & the chamber's throat diameter (.401", +.004" SAAMI)

The cartridge's outside diameter at the case mouth is .423" SAAMI.

In recent Handloader articles on the 40 S&W and the 10mm Auto, Brian Pearce reported that he measured the crimp on factory ammo that ranged from .4175" to between .420"-.422".

His advise is for a .002"-.003" taper crimp on these.

The OP doesn't qualify "what" his 40's will be loaded with or for, but if you're loading a copper jacketed bullet, for self-defense, with a full load of medium powder, I go with a .003" taper crimp at the case mouth on them.

If it's a plated swaged lead bullet I go a little less at .001" taper crimp.

If it was just plain lead, or a coated bullet, I'd go with .000" taper crimp at the case mouth.

Since you have ~.010" to .012" of a chamber shoulder for the case mouth to headspace on you'll have no issues putting a moderate taper crimp on your pistol cartridge's case mouth.

I've never had any such problems with jacketed or plated bullet headspacing improperly for that reason.

However, extra attention needs to be given when loading lead bullets as lead shavings can accumulate on the case mouth, when seating the bullet, which will mess with your headspacing.

.

[joeraf]

Thank you for that. Joe

[joeraf]

Is 4 grains of CFE Pistol in a semi 380 with a Hornady 90 gr XTP bullet a good load?

[joeraf]

Do reloaders choose starting grains or do they start with a load about half way between that and max? I’ve read you should and others wrote they start somewhere in the middle. I really wonder which is the best way and safe way.

[biku324]

The cautious way is safest.

[yeti]

Sevens post is a good read for any new pistol reloaders. Taper crimp probably should have been called de-flare or reshaping or something. It causes confusion.

On the starting load question. Pick a safe load and go 10% lower on charge weight. Ladder up to where you wish to be by producing test loads in multiple charge weights to test. I usually go 0.2gr apart, but this is up to you.

[bigedp51]

With a semi-auto, the bullet grip is controlled by how tightly the case grips the bullet. And all the taper crimp does is streamlining the case mouth for proper feeding.

Below a 9mm case was sized with a Lee undersize die and is wasp-waisted. Many competitive shooters who use range pickup brass use under-size dies. The more you shoot and resize a pistol case the harder the brass becomes and it will spring back more after sizing.

Bottom line, on pistol cartridges the taper crimp has nothing to do with increasing the bullet grip. And if you can see where the base of the bullet is on a reloaded case you should have enough bullet grip.

[joeraf]

Thanks everyone, this is a great forum. Thirty five years ago I started reloading, then quit for about 25 years.The equipment and info has improved immensely. I’m about to turn 82 years young, and it just gets better.

[Krogen]

Originally Posted by joeraf

Thanks everyone, this is a great forum. Thirty five years ago I started reloading, then quit for about 25 years.The equipment and info has improved immensely. I’m about to turn 82 years young, and it just gets better.

Welcome back! One of the things I like about this forum and the shooting community in general, is that age is irrelevant. We value the older folks who have travelled before us and the younger folks who will go after us. At my club, we have a 4-generational family that shoots matches together. Great-grandpa, Grandpa, Dad and the kids show up. We commonly get beat by the seniors. I expect before too long, the kids too.

[GeoJelly]

There is a ton of great information above, and very little I can add to it. That said, bullet setback is always a worry for me when loading for .40, 9mm or .45. Each time I set up for a different caliber, I load one dummy round first with no primer or powder. Then, I take that round and press it with my thumb as hard as I can against the tile floor. If the round can be shortened by any measurable amount, I recheck my dies and settings. I trusted the commercial reloading company, and didn’t do this check with some 9mm recently. I had a 9mm round set back a lot, fortunately the Glock wasn’t able to go into battery so it didn’t fire. I was using commercial once-fired brass that had supposedly been resized. As a result of that incident, I will never again use commercial resized brass. Just a heads up.

[joeraf]

The only thing I can’t find is primers.

[DeplorabusUnum]

Originally Posted by joeraf

Do reloaders choose starting grains or do they start with a load about half way between that and max? I’ve read you should and others wrote they start somewhere in the middle. I really wonder which is the best way and safe way.

The answer to this (for me) depends on whether I'm loading for a revolver or a semi-auto. Many times when I've loaded rounds at the suggested starting powder charge, there is not enough power to cycle the slide reliably, resulting in poor extraction and stove piped brass. Now I start in the middle and work up for semi-auto pistols. With revolvers, I've never had a problem starting low.

[joeraf]

That’s definitely helpful.

[Krogen]

Originally Posted by joeraf

Do reloaders choose starting grains or do they start with a load about half way between that and max? I’ve read you should and others wrote they start somewhere in the middle. I really wonder which is the best way and safe way.

Adding to Deplorabusunum's good advice: Some sources recommend recommend starting loads 10% below the listed maximum. In fact, that range is often what's published in load tables. Sometimes the range is greater, so starting in the middle about 10% below max should be fine. Then there's the old recommendation from Winchester about 296 - "do not reduce." These days, Hodgdon shows 296 with a starting load 10% below the listed max. On top of all this, you'll find different ranges in different load books. And, as Deplorabusunum said, the starting load may not cycle an action.

So.... starting loads require a bit of a judgement call. No hard and fast rule except "start below max." If you check a few data sources, start low, and don't make up a huge quantity of untested ammo, you'll be just fine. Just keep an eye out for something that's not right. Pressure "signs" have been widely discussed, embraced and debunked. But if you're sticking cases, jamming the bolt handle, blowing primers or getting abnormally high velocity, you're probably over pressure.

Handloading takes a dose of common sense and attention to details. With both of those in place, all is well.

[zeke]

.40 is high pressure round, and as others stated need good case grip. Might consider making a dummy round for the bullet/brass combo you are using and check for setback. And am not talking about pushing on dummy round with your hand, but loading it into mag, then using slide release from full lock back. Measure before and after.

Need to be especially careful with Rem brass and certain jacketed bullets. Double extree careful if loading for .40 BHP. The 40 Rem brass is thin and hard, while losing it's elasticity quickly. Imo hard brass doesn't spring back well, and the capability to "spring back" is what provides the case neck tension after seating a bullet.

[joeraf]

I finally got small pistol primers!

[joeraf]

Are the loads in Lee Modern Reloading as described in the aforementioned text?

[BLUEDOT37]

Originally Posted by joeraf

Are the loads in Lee Modern Reloading as described in the aforementioned text?

Specifically, what aforementioned text?

Lee Modern Reloading manual is a compilation of various free factory/manufacture's published data.

It's a handy source but doesn't include data from pay-to-view sources. As always, the more sources you have the better.

.

When you're working up a new load, if it's totally unknown to you, start low, only make two or three of that charge weight to try for function.

You can go back later, selectively testing ten or so of each charge weight for accuracy & grouping, to finalize a load.

.

[joeraf]

I meant the aforementioned text from Kroger. I have 7 manuals (some online) and prefer the Lee over the others, although they are all helpful. Some of the best help I’ve received has been from this great forum.

[dla]

Originally Posted by zeke

.40 is high pressure round, .

Same MAP as the 9mm - 35Kpsi.

The 40sw suffers from bad press because of Gen 1 & 2 Glock bulge makers (poor casehead support).

There are bullet/powder combinations that are less forgiving. E.g. 200gr and Hodgdon Clays. Bullet setback blows out cases.

And of course there are the KABOOM stories involving Titegroup and single-stage presses.

[dla]

Originally Posted by BLUEDOT37

Specifically, what aforementioned text?

Lee Modern Reloading manual is a compilation of various free factory/manufacture's published data.

It's a handy source but doesn't include data from pay-to-view sources. As always, the more sources you have the better.

.

When you're working up a new load, if it's totally unknown to you, start low, only make two or three of that charge weight to try for function.

You can go back later, selectively testing ten or so of each charge weight for accuracy & grouping, to finalize a load.

.

All good.
Now is a good time to pitch the idea that a chronograph is a darn handy tool for load development.

[joeraf]

Thank you. I’ve got one and I’m going to be using it.

[joeraf]

Is it necessary to size new pistol brass?

[Sevens]

That would be on a gun by gun basis. Some guns will not care, others will object if you don’t. So it makes good sense to yes, size all your new pistol brass also. As it is a necessary part of your typical operation anyway, it’s not going to be a good idea and skip it and take a shortcut.

[BLUEDOT37]

Agreed, don't skip resizing new/factory brass.

For straight walled pistol cartridges I can't envision the pistol having a problem as much as load development would.

All new brass I've checked with pin gages, before & after sizing, have had reduced diameter readings (inner) & longer OAL" readings (important when doing a length check, which yes I do on new brass too).

You'd be surprised what you'll find when you look. Assume nothing.

PS: And don't forget to chamfer/debur the inside of new case mouths, especially if you're loading lead bullet. They have a horrible rolled over edge you can even feel with your finger tip.

.