trimming a straight wall pistol case?

[JonB_in_Glencoe]

This comment (by DougGuy) posted today, in a taper crimp instead of roll crimp thread.
Doug, forgive me for copying your post to a new thread...but I have a question and I didn't want to derail the other discussion.


ROLL crimp for 44 magnum. Can't get the crimp super consistent because you will have slight variations in case length, some will crimp harder than others because of this. It is also not really recommended to trim revolver brass, you can but the gains are minimal for the amount of work involved.

First, I have never trimmed any pistol brass, never found the need for it...til the last batch of ammo I was reloading.

It was 41 Mag for revolver (as well as Marlin 1894).
using the Saeco 411 ( 230gr SWC)
If I'm using brass that is MAX length (per SAMMI) or less, I am able to crimp into the crimp groove (I'm using the Lee collet FCD) and achieve a COAL that works well in the Rifle and is right at MAX length to fit in the cylinder of my Mod 57.

I had accumulated a bag of used brass all with "W-W Super" headstamp, but it came from different sources. Some of them were .010 to .015 over MAX length...and they were troublesome to crimp, as the case mouth extended beyond the crimp groove and onto the driving band. After I figured this out, I pulled the few long ones that I loaded, then proceeded to sort out all the long ones in that bag, I found about 100 of them.

I figured I'd save those for "if or when" I ever attempt to make some 41 Mag shotshell ammo. But I also thought about trimming them...til I read Dougguy's comment.

Anyone ever seen 'stretched' straight wall pistol brass?

[Boolit_Head]

All brass stretches or grows over time through several processes. The rates may differ but eventually a trimming may be needed to get more uniformity.

[EMC45]

I trim and uniform all my straight wall pistol cases that get roll crimped. I also trim all rifle cases. You get more uniform crimps with trimming brass.

[JonB_in_Glencoe]

I've never noticed that any of my straight wall pistols cases have stretched?
Although, I suspect that heavy crimps may be the culprit to the used 41 mag brass I bought.

I recall reading that they actually shrink a tiny bit...but after a few firings and FL sizings they stabilize...or maybe they've work-hardened a bit? and that stops the shrinking?

[DougGuy]

i guess if you want to trim them for consistency it can't hurt, I know my own 44 mag brass was bought as a bag of once fired PMC and I can see some differences in the crimp from case to case but in shooting it at hunting distances, which it is a hunting revolver, I can't tell any difference in POI from those that the crimp looks like the case is longer and the ones that look shorter.

I also use a modified collet crimp die on my 44 mag and 45 Colt loads, I find that the added resistance against the boolit pulling crimp gives more consistent velocities over the chrony than roll crimping does. The post about the modded collet crimp die is here: http://castboolits.gunloads.com/showthread.php?201449-Question-about-type-of-crimp-required&p=2239315&viewfull=1#post2239315

Now I've really derailed the thread huh?

[dragon813gt]

Can't say I've seen any stretch. But I trim any cases that are going to get a roll crimp. I absolutely hate trimming brass. So far it seems it was a one time deal. My 357 mag brass gets used from almost squib to full tilt. Haven't had to trim any since the first time.

[Scharfschuetze]

Haven't had to trim any since the first time.

Same for me. Once is enough and only those lots (same headstamp) that will get used in competition, particularly the old PPC course's 50 yard stage which has a very small in width 10 ring. A single flyer there would land you out in the 8 ring to either side.

With cases of a uniform length for such shooting, you can be more confident of a uniform crimp from round to round. I don't wory about it for plinking ammo, nor do I worry about head stamp uniformity for shooting cans and brick-a-brack.

[EMC45]

I too will say once is enough. I also will say trimming brass is my LEAST favorite thing to do in the reloading world.

The reason I trim revolver brass is that I am a certified brass scrounger and I am always "finding" brass to reload whenever I shoot. I also am often given WalMart bags of brass by friends/family. All mixed head stamps and lots. Trim - I must. Like it- I don't!

[Petrol & Powder]

On rare occasions I've trimmed pistol brass but only when I was trying to eliminate all possible variations. For the most part, I never trim straight walled handgun cartridges. There just isn't much need or benefit.

Now, starting with all of the casings at the same length is an advantage when you're trying to squeeze that last little bit of consistency [read that as accuracy] from a load.

I can sometimes see slight variations in the crimp of straight walled cartridges when the cases are not uniform in length but unless it's severe; it doesn't affect accuracy enough to justify the trouble of trimming 500 cases.

[lar45]

Many years ago after repeated heavy loads, I setup to trim my 44 mag cases and only a few of them ever touched the cutter. So either they started out too short, or they never stretched.
I have heard of 500S&W brass stretching, but I haven't seen it on mine yet.
So I just don't trim straight walled pistol brass.

[country gent]

I lightly trim my pistol brass just enough to have square mouths and same case lengths on some batches this is .002-.005 on other batches it may be up to .010. I want the truly square case mouths and same case length for consistency. Its normally a 1 time thing and stays pretty consistant thru repeated loadings. Case do shrink a little when expanded by pressure to chamber dimensions then when sized they come back pretty close to the same, But this depends on how much your die is sizing the brass. I do trim pistol brass and also deburr and chamfer it when its starting out for the consistency.

[Xringshooter]

Last time I trimmed straight wall brass was when I was shooting PPC and wanted to get as uniform a crimp and length as possible on the HBWC rounds. Now that I don't compete anymore I don't worry about it unless I have a whole batch that is crimping hard then I check the brass OAL to see what might be the problem. I'd reload and end up splitting cases from use before I noticed any major stretching.

[dogdoc]

Never have trimmed handgun brass and most likely will not. Too much trouble for benefit. Rifle brass I do trim.

[dverna]

I believe one of the reasons Star offered a taper crimp die for the .38 Spl was to avoid the need to trim Bullseye brass. BTW, I have some that is 40 years old and have never trimmed a .38 Spl case.

[jetinteriorguy]

I don't believe that it's 'not recommended' to trim straight wall pistol brass. It's just that for light to moderate loads that don't need a crimp it's not necessary. But any loads requiring a good crimp to either handle recoil or for use in a lever action should be trimmed to the same length for best results. Just makes sense. Now, I've found with the Lee collet crimp there is a little more leeway on brass length and still getting good results. I love the collet crimper on both my .357 and .41.

[DerekP Houston]

All brass stretches or grows over time through several processes. The rates may differ but eventually a trimming may be needed to get more uniformity.

From the 45ACP durability testing I watched the round actually got shorter over time. IIRC it failed around 50 reloads, and it was from the primer pocket loosening rather than the brass stretching out of spec.

That being said I only trim 30-06 rifle right now, since that's the only one I reload for accuracy.

[FergusonTO35]

All my handgun shooting is done with rather mild loads. I measure and trim brass for my .38 Special defensive ammo as I find these shells usually have inconsistent OAL. One trimming is usually all it ever needs. Auto pistol brass is rarely trimmed as I find the OAL is quite consistent. I use the Lee tools for trimming. They are cheap and work well enough for me.

[Tom W.]

A long time ago I was recuperating from stomach surgery, so I decided to trim my .44 brass. Once. I never had that urge overtake m again.

[rond]

Never have trimmed handgun brass and most likely will not. Too much trouble for benefit. Rifle brass I do trim.

Same here. I do sort by headstamp and adjust the dies for the slight difference in length between headstamps.

[Char-Gar]

I have never seen straight wall revolver brass stretch, but I have seen cases with canalures have unven mouths when fired. I have also see brass of the same make and lot have different lengths.

I am one of a few who believe that uniform case length is important enough to take the time to trim all cases of the same caliber to the same length and so I do.

[Tim357]

^^^^^ what Char-Gar said

[Grmps]

Making an uneducated guess. Straight walled cases develop practically no pressure between the front and back of the case, just the boolit. With necked down cases, the pressure is applied against the front and back of the case as well as the boolit promoting more stretching.
Over multiple firings, the case will stretch a little BUT I think most cases fail before the stretching becomes an issue.

[rond]

Making an uneducated guess. Straight walled cases develop practically no pressure between the front and back of the case, just the boolit. With necked down cases, the pressure is applied against the front and back of the case as well as the boolit promoting more stretching.
Over multiple firings, the case will stretch a little BUT I think most cases fail before the stretching becomes an issue.

My guess is that the carbide dies most of us use now pushes the brass toward the head when sizing. I also think that bottleneck case are stretched by the expander button when sizing.

[EMC45]

Just to clarify - I don't trim revolver brass due to case stretching upon firing. I trim it due to getting copious amounts of brass from various sources from many different manufacturers. They are definitely not the same in regard to length. I like to set my dies up and not fool with them each time I get ready to load ammo. All brass uniformed, all dies stay the same. Easy.

[kayala]

I trim my revolver brass once, just to have consistent crimp. Got myself Dillon trim dies from ch4d so it doesn't take much time.

[pjames32]

I used to trim 38 special brass when I was shooting Bulleye competition for a uniform crimp. Not concerned with that now. My 45ACP brass has shortened over the years. I taper crimp it and keep loading it.

[tranders]

I trim my pistol brass for a more uniform crimp. If I'm using all the same brass it's normally not an issue,but I use range brass quite often.
Can't say if it makes them shoot any better,but in my eyes they look better.

[smkummer]

Yes, only mag pistol cases ever were long enough to even touch the cutter on the lee case trim gauges. One occasionally finds an exemption though that is over max. length and that is only because I picked up much used cases from gun shows.

[Harter66]

I ran a bunch of 357 many yrs ago . All went well then about 3 in a row bulged or collapsed . A quick reset and I was off again then I had 3-4 that had the crimp groove swinging in the breeze .
I had brass from 1.270 out to 1.297 . I set up the trimmer and cut it all to 1.285 several cases , oddly a larger number of nickle , needed to have a lot cut off .
I had a similar experience with 38s .

45 Colts I think are just all over the place in terms of length since all 8 chambers run long it's not a problem in the guns but I have cases in one lot for the BlackHawk that have probably 40+ cycles so the Colts get trimmed as they start to show crimp .

Dies and the effect ?
The Coke bottle look can't be good for brass life . I have 3 methods that so far are working to stop the abuse of the brass .
1 Carbide dies are only for neck sizing and then .1 shorter than maximum seating depth .
2 Universal decapping die and full length sizing the Colts and Schofield with a gutted Lee 45 ACP FCD .
3 still looking for a set of steel dies .

For autos I don't think I have since I had a bunch of 9mm with the headstamp all but gone and I ran about 200 of them and had about 20 with a full circle trimmed .

I would say that unless you have some that are very irregular , being over sized or for match work where it is about sub 2 dia groups that it just is a matter of comfort and confidence once a base line is established .
( I have 2 45 Colts Carbines that have 1.350-5 chambers for a 1.285 nominal case length and a Schofield chambered revolver at 1.110 for a 1.100 nominal case) .

[18Bravo]

On rare occasions I've trimmed pistol brass but only when I was trying to eliminate all possible variations. For the most part, I never trim straight walled handgun cartridges. There just isn't much need or benefit.

Now, starting with all of the casings at the same length is an advantage when you're trying to squeeze that last little bit of consistency [read that as accuracy] from a load.

I can sometimes see slight variations in the crimp of straight walled cartridges when the cases are not uniform in length but unless it's severe; it doesn't affect accuracy enough to justify the trouble of trimming 500 cases.

Agreed. The only pistol cases I trim are 44 mag and only when working up loads for best accuracy. As mentioned, it removes one of the variables from the equation.