Hello All,

I am new to reloading. I am about start my first batch of rounds (40 S&W) and I came across some information and I do not know if it is valid. It said that when reloading handgun rounds, it is not necessary to trim the cases or chamfer them.

Normally I am a "by the book" kind of guy but since I am so new I did not know if this is common knowledge and I would waste my time performing these tasks or if I should trim and chamfer. By the way, all of these cases are spent rounds from my Shield.

Hopefully, you guys with more experience can set me on the right path.

I've never trimmed or chamfered a straight walled pistol case.

I trimmed some .357 brass after 20+ loading. Other than that I've never trimmed handgun brass. Unless your shooting in competitions at 50 yards I wouldn't worry about it.

Revolver brass, yes; auto brass, no ( unless length is over max). Usually auto brass doesn't need trimming. If you're after maximum consistency, then you could if you wish. At the distances I shoot, (25 yds or less) and with me pulling the trigger, it doesn't make much of a noticeable difference LOL. :-)

Thank you all for the replies.

welcome to the world of reloading, it is full of questions for sure. Like the others here have stated I have never trimmed straight walled brass, never had a problem. Be diligent with your powder measurements and you should do fine.

Welcome to the wonderful, oft confusing and frustrating world of reloading...

Trimming handgun brass seems to be one of those personal alternative things. I started reloading in '69 and I believe I trimmed some 45 ACP about 20 years ago, once, but never any revolver or other semi-auto brass. Some do, but as I see it, it is not a necessity. If you feel comfortable trimming brass, cleaning, uniforming and deburring primer pockets in your .38 Special brass, by all means do so. It's your ammo, your time, and your money, and really not an issue. Reloading should be fun and relaxing (some say it's therapeutic), and it's not a "one method fits all" process. Just stay safe, follow load data in your reloading manuals and enjoy...

Most of us here don't trim/chamfer pistol brass, but the mouth is usually flared/exanded before bullet seating and being crimped. I have had occasion to trim some pistol cases, ONCE for the sake of uniform crimp with semi range brass that is often varying lengths.

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"He was kinda funny lookin'"

As I understand it, the only reason to trim revolver brass is to have the crimp fall consistently in the same place in the canelure each and every time. I don't worry about some crimping a little further north or south. I adjust for the middle, and they all fall somewhere within the canelure. I have scrounged brass, and some are a little longer, or shorter than the others.

Harris
Welcome...
You shouldn't arbitrarily skip steps.
Cases should be trimmed if they are too long.
I'd suggest measuring a good sample of your cases and check their length after re-sizing. You're new to this.....It's good for you to know any way.
If they are not too long, then they don't need to be trimmed and you're still "by the book"

Maybe someone who reloads the 40 cal can offer you tolerances.

After measuring 9mm and 45 ACP cases for awhile, I've found they do not need trimming.

I do however trim all my 357 cases to 1.280" and keep my 357 dies locked down for uniform crimps.

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I'd like to agree with you BUT

Like most others here I have never trimmed handgun brass either. Not handgun brass will actually shorten not lengthen when put through the dies.

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Freedom is never free!!
SWCA #3437

I've never trimmed a handgun case, revolver or pistol, and it's never been a problem at all. I do chamfer the case mouths as it helps prevent shaving lead bullets and also removes slight nicks and imperfections that can cause case mouth cracks. I rarely have a case crack.

Is it because I chamfer? Who knows--I just don't have a problem with cracks.

Is it necessary? Probably not, but it doesn't hurt.

Well, the main thing to realize is that straight wall semi auto brass does not "grow" (stretch) when being resized,

Some guys trim 357 Mag brass, to what is known as the "trim to length) that is so their crimps line up in the crimp groove or cannelure.

Even those once trimmed do not grow (stretch) much if at all.

The brass stretching is from when the case is resized.

Rifle brass (bottle neck) is a whole different thing, They do get longer and need trimming,

Hope that kinda makes sense.

If you are "by the book" that's a good thing! What manuals do you have? There is no substitute for reading the first chapters of them, Load data is just numbers.

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Still Running Against the Wind

It's not skipping a step it's just not needed for the most part. I do trim my magnum rev cases, the crimp is more uniform as they do tend to stretch with higher pressure loads. Service pistol cases; 9mm, 40 , 45acp, never trimmed one, never will.

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NRA Cert. Inst. IDPA CSO

I've never seen any semi auto rounds such as 9 MM or 380 Auto that ever needed trimming. However, like others have posted, I have trimmed rimmed cases such as 357 Mag and 44 Mag as they will tend to grow, especially if you are loading to higher velocities and pressures. And I like to keep the OAL pretty close on each batch (plus/minus .005) for more uniform roll crimps. Some of your slower powders such as 296/H110 need a firm roll crimp to get consistent velocities I find in 357 and 44 Mag.

I can see trimming a case if it is longer than the lot, if you are
crimping the bullets in the load.

Pistols chamber on the front of the case and revolvers crimp and get work hardened. I see no need to mess with the case unless it is out of round, too long or burred.

However some like to get all the cases in a lot at the same length for best results on the first loading. It is just a thing we do........ and no I don't drill primer holes.

Have fun.

Factory new brass needs to be chamfered.

When the factory cuts/trims them to length it leaves a rolled over edge on the inside of the case mouth. Use the tip of your little finger to feel it.

That edge will scrap/gouge lead & plated bullets on the first loading. Jacketed won't likely be damaged but the crimp will be uneven.

Lightly chamfer your new brass for it's initial use & it'll not be needed again.

If it's used/range brass you'll likely not feel that edge. If it's smooth don't chamfer it. Take a break then continue reloading.

.

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Waiting for the break of day

Good advice here. The rough edge on new brass can also cause the case to stick or hang up in the expander die.

You need to check lengths at least when you bring a piece of brass into your system. If you don't check, you don't know. If you want a consistent crimp, you need a consistent length.

You can get away with lots of slipshod practices. I don't recommend it.

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Just Say No - To Social Media

finally, one of two reasoned answers.

You trim based on case length. Case length is determined by measuring, not by asking on forums.

Does checking every last piece of brass sound like overkill? Sure, it does sound like it, but it's that, or run every piece through a trimmer, and then spot check a sample every so often.

Sent from my SM-G920I using Tapatalk

Depends on the cartridge, frankly, and its intended use.

You could measure once-fired factory .45 ACP brass and never find one that was anywhere near the maximum case length. They're all over the place.

Similarly, if you never shoot further than 25 yards with a handgun, you're not likely to notice a difference. Hell, even at 25 yards, my mixed-usage, mixed-headstamp .45 ACP brass shoots to call just fine.

The other thing is, just because it's the same length, doesn't mean it's the same! Cases split because they got brittle. They get brittle through a process called "work-hardening" that happens every time you resize, expand, seat, crimp, and fire.

A cycle or two in, and that process of work-hardening will make identical pieces of brass less so. They could all be the same length, but produce different pressure waves under identical conditions, because they've work-hardened differently.

If you want to obsess over accuracy, the answer is not to trim or sort your brass. You want to use factory-fresh or, at most, verified once-fired brass of the same lot. To explain by way of re-wording, if you buy 500 pieces of fresh Starline brass to use for 50-yard bullseye shooting, you'll have enough for 1000 loadings. 500 first-time loadings, and then 500 once-fired. After that, they get dumped into the short-line and practice bucket.

I suggest that, not because I care enough to do it, but because that's the way the AMU does it, and they're much better than I am.

Their resources also possibly exceed yours. All your other points are valid, and one of the reasons I don't pick up others range brass/

But again, ultimately, and without making this caliber/firearm type specific ("in a 38spl revolver, I would"):

Would you knowingly reload and shoot brass that is longer than max OAL?

All other answers flow naturally from the answer to that question: 1, measure. 2, trim to adequate length (all, or selectively those that fail test 1).

Well said

Measuring lengths, diameters, weights, etc., is an integral part of reloading and often gives answers to many issues. It also gives the reloader his or her own experience.
That said, shared experiences from forums are very valuable to confirming your own results.

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I'd like to agree with you BUT

Naturally. I am merely concerned that so few answers have anything to do with methodology or leveling.

No one actually asked OP questions like:
-where did your brass come from
-have you measured your brass; is your brass in spec?
-how many times has your brass been reloaded?
-what calibers are you reloading, or, are you reloading shouldered brass (357SIG, etc).

A ****-ton of assumptions have been made, and advice that may or not be accurate has resulted.

The only time I ever needed to trim handgun cases was when I used to develop really hot loads for a Contender. I've got .38 brass that I load 148gr wadcutters that I have probably reloaded dozens of times and are still in spec.

I have noticed some slight variations in case lengths with different 357 mag case manufactures. Enough to get less than stellar crimps when using the Lee seating/crimp die. No problem though when crimping separately with the Lee Factory Crimp die. If you are just shooting tin cans then nothing to worry about. I have not used the taper crimp die. I'm not sure one would or should use the taper crimp on a pistol round.

Some people do , and they do it every time....that's excessive OCD type behavior .
At first I did it , but only on the first reloading.
After reloading for 40+ years I have discovered it's not really necessary to do it any more than the first time . Chamfer only lightly to remove any rough edges, don't get carried away with it.
Flare the case mouth for proper bullet seating.
To be honest , I've stopped trimming and chamfering all straight wall semi-auto cases....pick them up and reload them, getting old and lazy !
Gary

Read the OP's first post. It says 40 S&W shot from his shield.

I wouldn't bother about trimming brass for semi. Having said that - I've went through my stash of 357 Mag today and trimmed it all to 1.280", just to have consistent roll crimp. Dillon trimmer made it pretty painless work (under 2 hrs for a little over 500 cases). 4 cases had their mouth untouched by cutter, so threw them to different pile. Measured them after I was done - 1.245" !!! They have 357 Mag HS but apparently someone cut them to 38 SP specs... Obviously it's not applicable to OP case but a reminder for me to pay more attention to range pickups.

Not trimming service pistol cases or chamfering is NOT slipshod methods. It's just a waste of valuable time.

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NRA Cert. Inst. IDPA CSO

Well, the AMU practice is also commonplace among civilian bullseye shooters. They're not working with unlimited manpower and money. They just have the easiest access to top-notch pistolsmiths, coaches, and more training time than most of us can dream of. Their procedures for loading and training aren't state secrets, and very easy to copy.

I would also suggest that the length issue has to be cartridge-specific. Why would you treat .38 Spl to the same process as .357 Sig (about the most dimensionally-sensitive cartridge I can think of)?

But more directly, yes. I happily pick up range brass for handgun cartridges and use it, worry-free. Give it a clean, inspect it when it goes on the shellholder, and have at it. Never found one that was anywhere near max length, anyway. Hell, never found one that was off very much from its...headstampmates? Headstampmates.

Not checking a piece of brass you bring into your system is slipshod.

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Just Say No - To Social Media

Don't know what you had there but my books call max for 357 at 1.290 and 38 spcl. max at 1.155, neither at 1.245?

I trim all brass -- rifle, pistol and revolver. I cannot see another way to get consistent crimps on straight walled pistol and revolver cases. I load cast bullets for all pistol and revolver cartridges. For pistol I only crimp enough to remove the belled mouth. Unless all cases are the same length it is not possible to get consistent results.

Yea, I've double checked 38SP specs later and you're right : my brass wasn't it. All problem brass was "Hornady" HS and @ 1.245", which as I understand below SAAMI specs (1.290-0.020)

Not what you originally said. I check my brass but leave the magnifying glass in the drawer.

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NRA Cert. Inst. IDPA CSO

If you think 0.001"-0.005" diff in case length is going to matter, well it just doesn't, at least not in handgun cases.

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NRA Cert. Inst. IDPA CSO

I have been reloading for nearly 30 years now.

I don't think I have ever measured a piece of empty pistol brass.

Maybe I didn't type clearly. Obviously, most brass is going to be close enough, depending on a persons ammo requirements.

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Just Say No - To Social Media

I know guys that get all wrapped up on chasing numbers. They measure everything, worry about 0.002" oal, 0.005" runnout, powder variations of 0.05gr, single digit std dev, all fine if you just like to do that, but doesnt really improve quality or accuracy or saefty of the ammo. I've proved it to myself several times, rifle & handgun.

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NRA Cert. Inst. IDPA CSO

Probably/possibly Hornady .357 Magnum140GR FTX ammo...? These cases are 1.250" MAX to 1.240" trimmed per the loading data I have...

Cheers!

But if the length tolerance is 0.01"...not 0.001" - 0.005".how do we know whether the case is less than minimum or over the maximum?

I'll except the answer that through years of experience one gets to know what their cases in their firearms do -during each cycle, but that's not skipping steps, that's applying your learned experience.

Hornady manufactures short 357 cases on purpose,as storminnorman mentions and some people trim 357 cases down to 38 special lengths. And then there's 9mm x 18, 19, 21 and 23 ? And that pesky 380 gets in the mix sometimes

I believe beginners should have some kind of measuring system step in their process.

Not all experience is transferable.

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I'd like to agree with you BUT

Thanks, that's what it is !

Because most of those questions have little to do with trimming or chamfering service pistol cases??

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NRA Cert. Inst. IDPA CSO

they relate back to some of the answers given.

I don't have enough invested in the answers to go through it Barney style.

Bottom line, the reason you trim cases is to make sure they are within specs. The safest way to know if a case is within specs is to measure. Any other answer is a product of conjecture, rationalization or worse, laziness. Experience, knowledge, years of doing it, all good but that doesn't measure your cases, let alone the op's.

Sent from my SM-G920I using Tapatalk

In handgun brass, exact length rarely matters. In rifle, yes, you have to check every 2-3 firings to make sure you are not beyond SAAMI max length. A case wedged in the rifling will spike pressures.
Handgun brass just doesn't stretch much if at all. Cases for my max effort magnums get trimmed to uniform length so because they will stretch a bit & affect crimp a bit. Semi brass just doesn't stretch any perceptible amount.

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NRA Cert. Inst. IDPA CSO

So one can sit for hours & measure every single case they have just to find out ALL are under max SAAMI length. Your time, have at it. Reality, it just doesn't matter. For rifle, yes, they should always be checked, but for diff reasons. There is diligent & there is anal.

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NRA Cert. Inst. IDPA CSO

You can measure with a caliper, use a case length gauge and sort it out pretty quickly, or do nothing. One of these options leaves something to be desired.

Anal, perhaps. Knowing for a fact that none of your cases are out of specs? The time it cost you. As the commercial would say, ensuring all your fingers stay attached to your hands? Priceless.

I venture that the next set of replies will go in several directions, including "Bah, no pistol/revolver will go kaboom over that", or "not in my 10,000 years of reloading have I seen a case stretch to that point", etc etc.

Very well. Carry on giving advice like that. I'm out of this one.

So, being realistic here.....

I just grabbed numerous samples of 9mm & 45 ACP cases from muliple storage cans which number in the thousands of empty fired cases. Some are once fired, and others have multiple reloads.

I couldn't find "one" case, that exceeded maximum case length. In fact, most will end up just shy of trimmed case length. Unlike rifle, these cases don't grow. If anything, they shrink a bit.

And that's why, as a normal course of doing reloads, I never sit & measure these cases. I'll do comparisons to factory ammo, once and awhile. Something that I always do, is check every finished load in a gauge or barrel. I never seem to have failures.

That's not really the point. The point is, if a person is loading 50 or 500 cases and they want a uniform crimp, it requires uniform length. Without checking, there's no way to be sure.

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