Case Trimming Questions

[DMW1116]

I was trimming some 38 Special brass and wondered something. Is there a standard relationship between max case length, trim length, and minimum length?

Cases ranged from 1.143 to 1.159 inches long. Trim length in the load data is 1.145. Max is shown as 1.155. A minimum isn’t listed that I saw. This is all nickel plated range brass of various head stamps.

 

[AJC1]

I was trimming some 38 Special brass and wondered something. Is there a standard relationship between max case length, trim length, and minimum length?

Cases ranged from 1.143 to 1.159 inches long. Trim length in the load data is 1.145. Max is shown as 1.155. A minimum isn’t listed that I saw. This is all nickel plated range brass of various head stamps.

I trim to 1.150 and scrap those less than 1.145. I do the same with 357 trim to 1.280 scrap at 1.275.

 

[243winxb]

38 Special...

SAAMI - 1.155" maximum to - .020 or shortest at 1.135" Any where inbetween is ok. Best if all the same, in same lot.

And now everyone will say "I never trim brass."

If 38 spec is fired in ONLY a 357 mag chamber, then no trimming required. Maybe, if same length.

 

[LV Gun]

I was trimming some 38 Special brass and wondered something. Is there a standard relationship between max case length, trim length, and minimum length?

Cases ranged from 1.143 to 1.159 inches long. Trim length in the load data is 1.145. Max is shown as 1.155. A minimum isn’t listed that I saw. This is all nickel plated range brass of various head stamps.

I trim all my 38 special to trim to length, they will grow again, but watch for the ring just above the case head (rim) if you start to see a distinct ring toss them they can separate,I have had it happen in heavy 357 loads it is called -incipient care head separation - it scared the hell out of me when it happened.

 

[DMW1116]

Anything 1.150 or less I didn’t trim. My trimmer cuts to 1.148 +/- 0.001 so there isn’t much point. There is one that measured 1.155” but the trimmer didn’t touch it. I may get rid of that one.

 

[film495]

I'm not 100%, but I think trim lenght, really means minimum length. you can trim to whatever you want, as long as it is between min and max. max as they show it is is max. for .38 Special, if I'm going to trim, I'm going to look for the shortest ones that are not too short, usually they are not too short, and I'll trim them all to that lenght. they end up the same, it is that much less material to remove than trimming all to minimum lenght, if I mess up, there is a chance to fix it by trimming more, and if they are all the same, the crimps are more consistent. If they are all within a couple thousandths in lenght and between min and max, I'm not going to bother trimming, for range practice plinking rounds.

 

[W.E.G.]

OK

I'm firmly in the "I don't trim" camp when it comes to pistol brass.

If I encounter a batch of brass that is so far out-of-spec that it crimps funny, I just send it to the recycle bucket.

Now, if you are shooting some sort of MEGA-BOOMER that might be causing heavy bullets to JUMP-THE-CRIMP, then you gotta crimp hard. And if overall length of your MEGA-BOOMER brass is messing up the consistency of your crimp, then you probably should trim it all to a consistent length to be sure you get the best possible consistent crimp.

And that said, my .38 wadcutters aren't "jumping the crimp" on the light roll-crimp I apply to straighten-out the bell on the mouth of the case. Not even a little bit.

I occasionally handload some .45 ACP and 9mm. Those calibers don't seem to be jumping either. They get a taper crimp. And I'm definitely not loading MEGA-KER-BLAMMO .45 or 9mm either. Those rounds headspace on the case mouth. So same deal, if they gage funny, I can usually track it down to some particular lot/headstamp. I've got a lot of brass, and not a lot of time. So the particular lot/headstamp that gages bad gets thrown in the recycle bucket. I'm not gonna trim .38 or 9mm or .45.

I handled a .480 Ruger snubnose at the gun show this week. Now, if I were handloading for that, I'd want all the crimp I could get. But I gotta say, just lifting that thing off the vendor's table, my only thought was "What kind of masochist?!..."
No, I won't be trimming any .480 Ruger brass either.

 

[W.E.G.]

I'm interested in the fella who said he got a case-head-separation with a straight-walled pistol case, and allegedly due to the straight-walled pistol brass "stretching."

Tell us more about that.

I've seen countless case-head-separations with bottleneck cartridges. Never has the separation caused any drama except tying up the gun until the front half of the case could be fished out of the chamber.

And let us VERY IMPORTANTLY contrast two case failure events:
1. CASE HEAD SEPARATION; versus
2. CASE HEAD RUPTURE

Each of those events is a completely different type of failure. The former being only an inconvenience. The latter (CASE HEAD RUPTURE) being BIG DRAMA and dangerous.

 

[DMW1116]

These are target loads so pressure and projectile movement in a Blackhawk 357 Mag aren’t issues. I trim revolver brass the first time I reload it. Any 9mm brass over max gets saved. It’s very few that are too long. I think I have a dozen or so. Eventually I’ll have enough to justify buying a 9mm trimming die. If I bothered to pick it up, a little trimming won’t stop me from using it.

Is the minus 0.02” standard or specific to caliber? I’ve looked this up in SAAMI specs for 223 and it was the same or similar in that it was 1.760-1.740 inches. I kept finding brass that was 1.743” and wondered how low it could go. My trimmer is a fixed length. Any cases less than trim length for my trimmer don’t get used for load testing but I’ll use them in production.

 

[243winxb]

Is the minus 0.02” standard or specific to caliber?

Down load the SAAMI Standards. It gives max & min trim lengths. Some cartridges that headspace on the case mouth get little to no trimming. Like 9mm, 45acp.

The 223 is 1.760" - .030" There is no good reason to trim this short 1.730" Standard is trim back from maximum - .010" The RCBS X die reguires - .020" shorter then maximum.

 

[AJC1]

Down load the SAAMI Standards. It gives max & min trim lengths. Some cartridges that headspace on the case mouth get little to no trimming. Like 9mm, 45acp.

The 223 is 1.760" - .030" There is no good reason to trim this short 1.730" Standard is trim back from maximum - .010" The RCBS X die reguires - .020" shorter then maximum.

I agree, 223 necks are plenty small. I have my trimmer set to 1.758 and they all go through every time. Generally the range pickups cut a lot, and mine barely any or just enough to square up.

 

[Palladan44]

I've never trimmed 38 special brass, ever.
They all go in wheelguns, and all light taper crimps are used. They could literally vary in length by a sixteenth and I'd probably never notice. I see some variance in lineup of cannelures with the rim, but I don't care, it doesn't matter.

I trim 357 Mag Only if I'm loading with WW296 and roll crimping in the cannelure, but that's about it.

Hopefully someday ill own a 38/357 levergun.....

 

[DMW1116]

Why is there such an objection to trimming pistol brass? I’ve seen it in several threads and can’t quite understand. I’ve trimmed all the pistol calibers I use. At the very least I run cases through my calipers set at max and save or trim as needed. The saved ones I’ll keep until I have enough to be worth trimming.

 

[AJC1]

Why is there such an objection to trimming pistol brass? I’ve seen it in several threads and can’t quite understand. I’ve trimmed all the pistol calibers I use. At the very least I run cases through my calipers set at max and save or trim as needed. The saved ones I’ll keep until I have enough to be worth trimming.

I believe it's a volume thing. Most people shoot a ton and don't see the value of return in trimming. I love the look of a good roll crimp, just makes me happy.

 

[Palladan44]

Why is there such an objection to trimming pistol brass? I’ve seen it in several threads and can’t quite understand.

No objection to it, but my time gets consumed with other things that are more important.. which right now is trimming rifle brass And that sucks up the majority of my time I spend in the reloading room. And conveniently, a lot of pistol brass shrinks in length anyways.

I'm also thinking its an accuracy thing.
A seasoned competitive pistol shooter (actually lets just jump to the top and say Jerry Miculek, that sounds better) could outshoot me with a stock Glock 17 loaded with the cheapest, out of spec ammo on the planet as long as it went "bang" That's the unfortunate truth about handgun shooting and accuracy. Vs me with take your pick best handloads and tricked out race gun...Jerry would win, guaranteed.

Now, Rifles, different story. If You give Jerry some ammo that can't shoot 2 MOA and you put him in a benchrest match, he will lose to the juniors. Why?
Cause the ammo.

Additionally, proficiency with handgun takes tens of thousands of reps (annually), and no damn way I'm trimming that many cases.

 

[cfullgraf]

Magnum ammunition gets trimmed because it gets roll crimps. All the cases need to have uniform case length for a uniform roll crimp.

I mostly load target ammunition with 38 Special. I taper these rounds primarily to remove the bell mouth of the case formed when sizing and mouth expanding.

Most semi-auto ammunition, I do not bother to trim as it gets taper crimped.

An odd example, I form and load 38/45 Clerke ammunition. It gets trimmed as part of the forming process but it never sees a trimmer again for the life of the case.

30 Carbine is another anomaly, the cases do stretch during firing. I measure and trim those that are too long. I do taper crimp this ammunition.

Trimming can't hurt if you got the time. In my opinion, it is not always necessary with straight (or taper) walled cases.

Bottle neck rifle cases are another kettle of fish.

 

[armoredman]

I confess I am also one who never trims pistol brass, and I agree - case prep for rifle brass is very time consuming, but worth it in the end. I haven't had any issues with pistol brass growing yet.

 

[DMW1116]

It’s interesting to me that by far the worst case to trim is 223. 38 and 357 trim really easy and aren’t a problem in terms of having to remove a lot of length. The few 9mm I’ve trimmed were also easy and quick. I’ll measure them whenever I load them but I don’t anticipate having to trim revolver brass but once. I roll crimp revolver brass but use the lightest I can get away with. 357 Mag is the heaviest revolver I load

 

[Soonerpesek]

It’s interesting to me that by far the worst case to trim is 223

30 Carbine grows like a weed also…..!

 

[EricBu]

I was trimming some 38 Special brass and wondered something. Is there a standard relationship between max case length, trim length, and minimum length?

Cases ranged from 1.143 to 1.159 inches long. Trim length in the load data is 1.145. Max is shown as 1.155. A minimum isn’t listed that I saw. This is all nickel plated range brass of various head stamps.

SAAMI determines the max and minimum. The "Trim To" length is somewhere in the middle...the safe play is using your load manual's trim to length....but some like to trim closer to min (on bottle neck rifle for example) so they can go longer between trimming. On a straightwall (revolver) the only reason to trim is to have a consistent crimp depth for the roll crimp...it doesn't really matter what you trim to, as long as it's within the spec and you trim them all the same, so that your bullet will seat to the same depth, and your crimp will line up with the cannelure the same way every time. Most shooters don't trim revolver or pistol brass at all TBH, and some (like 45 acp) is at least as likely to get shorter over time than longer (web collapses over time). Generally, pistol rounds don't use a cannelure, so the taper crimp doesn't care. There is some merit to trimming straightwall revolver for match shooting...but if you aren't shooting 44 Mag silhouette at 200 yards in a revolver...you probably don't need to bother unless you are doing relatively low numbers and it makes you happy.

 

[IWAC]

With Revolvers, It's the Max Cartridge length you have to watch. Too long, and the bullet will stick out beyond the cylinder, and possibly tie up the gun. Shorter, it really shouldn't matter, but some guys trim all of their brass to match the shortest case in the pile, for crimp consistency. Personally, I don't know if that level of attention, seeing as a human hair averages .003" , is really necessary for the majority of handgun reloading...maybe for semi autos, but revolvers? An unresolved question, at least in my mind. That said, I just purchased a new case trimmer!

 

[9mmepiphany]

Cases ranged from 1.143 to 1.159 inches long. Trim length in the load data is 1.145. Max is shown as 1.155. A minimum isn’t listed that I saw.

I've always trimmer my .38Spl cases so I get uniform expansion (to avoid shaving) and uniform roll crimp in the crimp groove (otherwise it looks sloppy). I only trim 1200-1500 cases each year for matches...you only have to trim them once.

Even matched headstamps will run quite a variation in length. I had a several thousand left over W-W Super Match cases from when I used to shoot PPC and measuring them was quite eye opening...I only measured because I wasn't getting uniform expansion of the case mouths and was shaving the coating of the polymer coated bullets. I might be a little fussy about my ammo, but I use a M-die profile Redding Expanding die, Redding Competition Seating die, and Redding Profile Crimp die.

I use the Lyman E-ZEE Trim system in my drill press and set the pilot rod to trim to 1.145"...uniformity is more important than exact length. Any cases that are shorter get tossed in a container with cases that I use to load plated bullets

 

[Rodfac]

I trim all of my revolver brass, once, which allows for a uniform crimp. As the brass ages through multiple firings I see very little variance in length. For working up loads, shooting from a steady rest, there's a slight difference in group size using that method. Offhand, from any reasonable field position, I can't see the difference.

Auto brass is a different kettle of fish since it headspaces off the overall length and employs a taper crimp. 9mm cases seem to vary considerably in length and if working up a load, I sort them by length. Both .40 S&W as well as .45 ACP don't seem to vary as much, in my experience. I sort all of it by head stamp, but rarely for length within any given headstamp.

HTH's Rod