Case trimmer

[natitude]

Newbie question. Do you trim 9mm cases? I've read yes and no, so thought I'd ask here where I can trust the responses. And if answer is yes.. What are some good ones y'all recommend? Thanks.

"Protected by Shield"

[Vlad]

no. I never trimmed any handgun brass.

[mikeyjones]

Been reloading for years. Never trimmed a single piece of handgun brass.

Sent from my ONE A2005 using Tapatalk

[BeerBaron]

No. No need to trim any handgun brass really. Perhaps some of the bottle neck calibres if you're really serious.

But for 9mm, 40, 45, 38 super, 38 special, 357 mag etc there's no need to trim.

[noylj]

Why would you want to? You trim because the case is too long for the gun's chamber. Straightwall cases don't grow. Don't grow, don't need trimming. Next, the cartridge is supposed to head space on the case mouth. Trimming the case increases head space. Increasing head space hurts accuracy. I find that if I want accuracy in 9x19, one of the easiest steps is to sort my cases by length and save the longest for when I need the accuracy.

So, what reason did any one have to trim?

Same old "any thing that increases consistency makes it more accurate," so you consistently make all cases less accurate by increasing head space?

IF your reloading manuals don't tell you it is important, it really is not important.

[natitude]

Thanks guys! I figured it was a no. Just wanted to be sure.

"Protected by Shield"

[kidmcclintock]

Newbie question. Do you trim 9mm cases? I've read yes and no, so thought I'd ask here where I can trust the responses. And if answer is yes.. What are some good ones y'all recommend? Thanks.

"Protected by Shield"

No sir, you don't have to trim pistol brass.

[kidmcclintock]

Anybody using the Frankford Case Trim and prep Center?

[natitude]

Newbie question. Do you trim 9mm cases? I've read yes and no, so thought I'd ask here where I can trust the responses. And if answer is yes.. What are some good ones y'all recommend? Thanks.

"Protected by Shield"

No sir, you don't have to trim pistol brass.

Thank you sir!

"Protected by Shield"

[Tom S.]

The correct answer here is you don't trim straight walled pistol brass. There are pistols that use bottle necked rifle brass, such the Remington .221 Fireball, and those cases do need to be trimmed occasionally. But 9mm, .38/.357, .40 .45 and the like can be left alone as far as trimming is concerned.

[JLarsson]

Well.....I guess I'll be the voice of dissent.

For taper-crimped cartridges, minor variations in case length isn't too big a deal. These cartridges DO headspace on the case mouth, so if the cases were too long for some reason, that might create an issue for chambering. On the other hand, if they are too short, it could create an issue with ignition.

ROLL-CRIMPED cartridges, on the other hand, should be pretty darn close to each other for consistency of crimp, and especially so if seating and crimping in the same operation. These cartridges, .357 Mag, .44 Mag, etc. typically headspace via the rim, so chambering and ignition aren't usually a problem (though a too-long case COULD present issues of chambering). It isn't necessary that all the cases match some arbitrary measurement as much as they match each other. If new, out-of-the-box cases vary too much in length, trimming for uniformity may be necessary. One additional benefit is with a roll-crimp, more uniformity results in better long-range accuracy, if the gun and shooter are capable.

[noylj]

Why would you WANT to trim pistol cases?

You trim cases for ONE reason: they exceed max length.

So, you don't trim cases unless they exceed max length.

After sizing, check your 9mm cases and they will ALL be well under max length.

In fact, you should set the longest cases aside and compare them and regular cases for accuracy. My results were that the LONGEST cases were the most accurate.

Bottleneck cases grow because the case head is pushed back to the breech (like all cases), but the shoulder is pushed forward, which causes the case to stretch and grow in length.

Straightwall cases don't grow, since there is no shoulder to stretch the case and make it grow.

Now, if you have a bottleneck case that head spaces on the case shoulder, you can trim the case neck almost as much as you want since you aren't affecting head space.

However, if the case head spaces on the case mouth and you trim the cases, you have increased head space. No one has ever claimed that increasing head space improves accuracy.

Revolver cases, that head space on a rim at the case head, can be trimmed without affecting head space. They don't grow and never need to be trimmed, but some folks are convinced that their revolvers are so accurate, that they really get a little extra accuracy by trimming their cases (you know the mantra: consistency ALWAYS improves accuracy so the ROLL crimp is the same. I played this game years ago and found that it made no difference with my S&W M52's and really made no difference for any .38 Spl, .357 Mag, or .44 Mag revolver I had. A revolver that can't shoot 5-shot groups under 0.5" at 100 yards will NEVER be able to show any improvement from trimming for crimp consistency. Crimp is just so far down the list of accuracy variables, that I doubt any one can even measure the effect.

One thing we need: a lot more reloaders TESTING the toys they are offered and a lot fewer just believing the tripe the magazines feed them. I do not understand the belief that things the long-distance rifle crowd do (and, again, many are unproven and fall into the "consistency ALWAYS improves accuracy") can have any effect with handguns that are generally lucky to be shooting 4" groups at 25 yards and often are only producing 4" groups at 7 yards--other than, if it makes you feel batter, maybe you'll do better.

Edited March 15, 2016 by noylj

[JLarsson]

I realize the OP was asking about trimming 9mm. And barring cases that are too long to chamber properly, no, there isn't a need to trim them.

I was trying to point out that there are SOME circumstances in which trimming of SOME handgun cases is desirable or even necessary. One I forgot to mention was when using a roll crimp with cast bullets. Cases that are too long to be crimped properly into the crimp groove will shave and/or deform the forward driving band. Not MY idea of a good thing.

But that's just my opinion. You're certainly welcome to think otherwise if you wish.

[noylj]

>I was trying to point out that there are SOME circumstances in which trimming of SOME handgun cases is desirable or even necessary. One I forgot to mention was when using a roll crimp with cast bullets. Cases that are too long to be crimped properly into the crimp groove will shave and/or deform the forward driving band. Not MY idea of a good thing.

>But that's just my opinion. You're certainly welcome to think otherwise if you wish.

Thank you for letting me think my own thoughts.

MY point was--you trim cases because of some real need, and not as something to do.

Could you tell me when you have ever needed to trim a case because seating a bullet such that the case crimps into the crimp groove would produce a COL too long for the gun's cylinder? This may have happened, but I have only read about about this for very long heavy SWC bullets in revolvers, the solution for the last 100 years was to crimp over the bullet shoulder. Now, of course, there are the squeeshy-rubber tipped bullets from Hornady, but these don't apply to the simple question the OP posted.

Just so you know, I have nothing against trimming a case if you NEED to. But, having loaded for semi-autos, revolvers, and single-shot handguns for over 40 years, I have NEVER had a NEED to trim a case used in a handgun, except for 7mm TCU bottleneck cases. Nor have any of my tests over this time ever shown any improvement in accuracy by trimming cases for straightwall pistol cases.

The cannelure and crimp grooves on bullets I have used are all wide enough that all cases that I had crimped perfectly and I really don't think you can hand-wave a need based on something that rifle shooters do hoping to shrink groups by 0.1" or less as actually having any effect on any common hand gun. However, I would love to read of any actual testing you have done to prove that did help--and I am serious about that. Test and prove, don't assume.