How Important Is Trim Size?

[BigN]

I'm reloading some 357 mags in Rem brass now and according to the Hornady Manual, correct trim size is max 1.29 and min 1.28. Most of the brass falls in between those but several are in the 1.275-1.279 range. I can see the problem if it's too long but is this close enough or not? What types of problems are looming on the horizon if I load a piece of brass too short?

 

[Slamfire]

Short is not a real issue especially in revolvers. People used to shoot 38 Specials in their 357's for practice and carry the full length 357 for serious work.

With shorter cases you can build a wax or crud ring in the cylinder. That can be a bother to remove.

When you are talking about differences in .01", that is not significant.

For all cases, rifle and pistol, you do not want the case so long that the case neck is pinched in the throat. That will raise pressures.

I never trim my 357 brass and I have never had a problem. Unlike rifle brass, the stuff has not "growed" enough to be an issue.

 

[Walkalong]

I trim to 1.280, but short cases pose no safety risk. Crimps will not be as consistent as with trimmed cases, but many never trim them.

 

[TonyT]

I trim rifle brass but have never trimmed any of the handgun brass whcih I reload.

 

[BADUNAME37]

I don't understand those who claim they have never trimmed their pistol brass.

When I seat a bullet, I want every crimp to be identical in the cannelure.

How does one achieve THAT - if their cases are a mix of new cases along with cases that have been fired any number of times, between once and twelve different times?

When I seat my bullet and then put a taper or roll crimp on it, I want all my cartridges to crimp the same - and I surely do not want to be sorting my brass by length as it would take me less time just to run it all through my trimmer than sorting it all out! As it is now, my dedicated crimp dies are all set up for each caliber, I never need to adjust anything as the cases are always the same (give or take one or two-thousandths).

I reload for several reasons, one of them being that my reloads are more consistent than factory loads. If I never trimmed my pistol brass, I could no longer state that my reloads are more consistent than factory loads, because they simply would NOT BE!

I could compare it to cleaning my guns. I could just wipe them down with oil after I shoot them, and many times, I do. However, it does get to a point where I must clean inside the bore to remove lead and copper fouling. To me, stating that one never, EVER, trims their brass is like me hearing someone say "I never have to clean my bore, in fact, I don't even own a cleaning rod -- I just wipe the gun down after use with an oily rag!"

 

[GLOOB]

Revolver brass is a special case. You do not lose cases. And for the most part you do not find once-fired cases. So a lot of people start with relatively uniform cases, either through buying new brass or by shooting a bunch of their preferred plinking ammo. I wouldn't trim this brass unless it was too long or unless the crimps come out noticeably inconsistent.

If you have a hodgpodge of cases with wildly varying lengths, you'll notice a problem with inconsistent crimping. Then you can trim to the length of the shortest case. Even though it's a lot of work, you'll be shooting the same cases for a long, long time.

Straight wall semi auto pistol brass doesn't lengthen, which is a good thing. Because unless you have a private range, you'll pick up some random brass with your own. If you try to trim it, you'll end up having to measure all your brass every time you shoot it to find the stragglers. Most people do not trim semi auto pistol brass.

 

[gamestalker]

I keep all my pistol brass trimmed to the same length. That length isn't always the "trim too length" but remains under the SAMMI maximum length for that cartridge and above the SAMMI minimum. And as someone else already addressed, I like my crimps to be consistent, because this is where problems can develope when dealing with pistol brass. Even with AL brass I like them all the same length for reasons being crimp, and also because AL brass head spaces at the mouth.
Rifle brass is a bit different in that I don't utilize a crimp but I certainly don't want my brass growing beyond the SAMMI maximum. Pressures can spike unpredictably high if the mouth gets pinched in the throat.
Recently several of us have addressed the safety issues regarding reloading due to some posts about firearms that KB. Bottom line fellas is, if you follow the proper reloading process, and don't skip any of the procedures, you'll most likely have a safe and enjoyable hobby without incident. When you begin looking for short unsubstantiated short cuts, or try to eliminate certain steps based simply on someone elses general opinion, you could be setting yourself up for some degree of failure or worse.

 

[mdi]

I have to admit, I don't bother to trim my revolver brass. I used to measure all my brass, but finally gave it up 'cause my reloads didn't "grow". I usually go with mid range loads in my 38, 357, .44 Spec and .44 Mag., and case length has never been a problem...

 

[Hondo 60]

I never trim straight-walled pistol/revolver brass.
So a few thousands long or short makes no difference to me.

 

[41 Mag]

I don't understand those who claim they have never trimmed their pistol brass.

When I seat a bullet, I want every crimp to be identical in the cannelure.

How does one achieve THAT - if their cases are a mix of new cases along with cases that have been fired any number of times, between once and twelve different times?

When I seat my bullet and then put a taper or roll crimp on it, I want all my cartridges to crimp the same - and I surely do not want to be sorting my brass by length as it would take me less time just to run it all through my trimmer than sorting it all out! As it is now, my dedicated crimp dies are all set up for each caliber, I never need to adjust anything as the cases are always the same (give or take one or two-thousandths).

I reload for several reasons, one of them being that my reloads are more consistent than factory loads. If I never trimmed my pistol brass, I could no longer state that my reloads are more consistent than factory loads, because they simply would NOT BE!

I could compare it to cleaning my guns. I could just wipe them down with oil after I shoot them, and many times, I do. However, it does get to a point where I must clean inside the bore to remove lead and copper fouling. To me, stating that one never, EVER, trims their brass is like me hearing someone say "I never have to clean my bore, in fact, I don't even own a cleaning rod -- I just wipe the gun down after use with an oily rag!"

X2

I am the same way. It just don't make sense to me to do any other way.

Yes there are times that I won't trim a batch of cases, but when I start them out as new from the box, I measure them all and trim to the shortest length. As mentioned this at least sets them all up for the same crimp length and pressure from the get go.

It only takes a few minutes to check 50 - 100 cases with digital calipers. Just zero them, then measure the first case, and hit zero again. IF they are within +/-.002, they go in the box as I haven't noticed this being much, making much if any difference in my groups. Any more they go in the can for that caliber, until I get the can full of ones that need trimming. Then I repeat the procedure.

For me it don't matter if it's rifle or revolver, I keep track of them when I load. The pistol cases I load for are only two calibers being 10mm and 45acp. The 10mm is pretty close and has to be kept in check, the 45, well it's like a brush hog, it just seems to eat what ever will fit in the chamber. I do however check all loads before boxing them in the barrels for both pistols. If it don't chamber it gets culled.

 

[GLOOB]

I never trim straight-walled pistol/revolver brass.
So a few thousands long or short makes no difference to me.

It wouldn't bother me, either. A few thousandths, no sweat. And straight walled brass is almost never too long.

But when you get a batch of revolver brass that varies by several hundredths and try to put a roll crimp on your ammo, you'll see what we mean. But trim ALL my pistol brass? Heck no. I don't fix a problem that's not there, esp with semi auto brass that'll get mixed up every time I shoot it.

 

[jmorris]

Must not be to important of the case has no bottle neck. I have loaded hundreds of thousands of rounds over decades and have yet to trim a straight walled case.

 

[dickttx]

I have started to trim handgun brass a few times using the Lee trimmer. Very seldom the cutter even touches the brass. Always quit after a dozen or so rounds.

 

[janobles14]

i only trim pistol brass if i care enough to separate by brand. i carry reloads for defense and these are always of the same brand (usually speer or federal) that are hand selected. now i do trim these though it may not matter, to be honest. they still shoot EXACTLY the same as my practice loads. but to each his own.

now for plinking rifle brass i only trim if i get the "stink eye" from a piece that looks wrong. for hunting loads and home defense loads i trim like a mad person after i sort by brand (usually hornady or LC).

 

[gamestalker]

With straight walled pistol/revolver brass I trim if it gets to the maximum, and also to keep them the same length for crimping reasons. Often times I keep the brass trimmed to the same lengthat some where between the max. and min.. This is so I can keep them the same length and is especially so after the first couple of loadings when the brass has stopped growing.

 

[41 Mag]

I know a lot of people who think that the below group is pretty decent for 25 yards off hand, from a 8 3/8" Raging Bull in 454 Casull.

and these same folks are quick to tell me the merits of not trimming their cases as it is a big waste of time and effort on straight walled cases.




Personally the one below is much more appealing to me,


While all of these rounds were loaded into the same batch of cases, which were all trimmed to the same lenght, the powder charges in them were not the same. I also found that with one powder as noted in the groups, the revolver liked the harder water quenched bullets over the air cooled ones.

Either way you slice it, if it works for you run with it. Personally I like mine all trimmed, just one less variable to be removed from the overall equation, and while I "might" be able to shoot groups like the one above with untrimmed cases, I know for a fact I can easily duplicate it with trimmed ones. .