To Trim or Not To Trim

[AF_Reloader]

Avid THR reader, first time poster.

Got a two-part question about trimming cases (as you can guess from the title):

1. I've looked in my Nosler and Speer manuals, and although they both mention case trimming, I'm trying to pin down exactly when to trim cases. I separated 50 .270 Federal cases into a lot for reloading, and after full-length sizing there were a few that were above the 2.540 maximum cartridge limit (2.544 average). The trim length in my book says 2.530. Well, I didn't know if I should trim the majority of the cases that were 2.535-2.538 down to 2.530 as well, but they're just Federal cases, so what the hell I trimmed them down. I know brass I trimmed off has to come from somewhere, and I know you don't trim cases every time, so I'm looking for guidelines on when to trim. Instead of the trim length, should I just cut them down to 2.540? If I do trim them, do I trim the ones that are under the max length, or just the long ones? Is there an average length I could shoot for instead of them all going down to 2.530? Just FYI, about half of these cases were given to me, so not all are fired by my own Ruger Mark II.

2. Okay, this one is easy. I got a little overzealous on a few cases, and several are down to 2.528-2.529. Are these gonna be okay, or do I get rid of them?

Sorry about writing a book, but this is one of the last questions I'm stuck on before building my first loads. Thanks!

Frank

 

[1858rem]

i actually dont have much experience trimming either, i shoot 45 colt an 38 spl ...trimming about every three firings. i use the lee trimmer and LENGTH GAUGE thathas a pre set length you trim to. you just cut it on down untill it stops cutting, chamfer the mouth and you are set, only a few bucks to get em too.

for the short ones.... i think you may be able to just seat the bullet to the same overall length and be ok... or you could try resizing the neck a bunch to try and stretch it back out... to be honest i dont have any experience reloading rifle rds yet and would appreciate any additional info also.



and welcome to The High Road

 

[1858rem]

also curious why 50 rds? not 40 or 60? were they reloaded before and worn out to where he had to toss them... maybe why your cases were so long?

 

[AF_Reloader]

Heh, I don't really know why I reload in lots of 50. I do the same for shotshell, and the habit just carried over.

All the brass I have is once-fired, so it shouldn't be worn out.

 

[Shoney]

AF_Reloader
WELCOME! to THR

When you chamber cartridges with case length greater than max trim length, it is usully harder to get the bolt down, as a first sign. Longer yet and you cannot close the bolt at all.

The danger in the long cases is that the bore in front of the chamber is pinching the brass down on the bullet. This can result in high pressure spikes. So, any time they exceed the maximum trim length, you should be trimming.

Those cases that are short are perfectly safe to shoot. They should probably be used for fouling shots until they lengthen with each sizing.

Good Shooting!

 

[ReloaderFred]

In answer to your original question as to when to trim, and which ones to trim, whenever you trim brass, you should trim the entire batch. This gives you a uniform length for bullet tension and crimping.

I make it a habit to trim every time I load rifle rounds, for consistency.

Your short cases are perfectly safe to shoot, and if you're just plinking, you won't notice much difference in accuracy, though it would give you a perfect opportunity to do some accuracy testing with cases of different lengths.

Hope this helps.

Fred

 

[qajaq59]

I usually start measuring my rifle cases after about the third time they've been fired. If I find any long ones I do the whole batch of 100. Some will need the trim and others may not, but at least they all end up the same length. Be sure you measure them after they are sized.

 

[AKCOP]

As you mentioned that brass has to come from somewhere so in addition to trimming keep close track of how many times you have loaded and trimmed since you really want to avoid a case separation at all cost. If you are loading hot, your brass will flow more and you might also look at having to turn your necks down as well. You should be able to find more info on that in your loading manual. Good luck

 

[USSR]

...whenever you trim brass, you should trim the entire batch. This gives you a uniform length for bullet tension and crimping.

+1.

Don

 

[AF_Reloader]

Outstanding, thanks guys.

Several of you mentioned trimming the whole batch, for consistency, and that's what I was looking for.

Thanks again!

Frank

 

[dardascastbullets]

AF_Reloader,

I assume from your post that you do not have a case gauge. Your question will be answered when you obtain one and see if you have growth. A comparison can then be made along with the decision to trim or not to trim.

 

[rcmodel]

Sounds like he's got a case guage, in the form of a dial caliper probably.

Otherwise, he wouldn't have had all those measurments available in the first post.

rcmodel

 

[Dallas Jack]

The first time I load new or once fired brass I size and trim. I will generally trim to the length of the shortest brass in the bunch as long as it is in spec. I trim mainly to assure consistant in spec length. Check and trim as needed.

Triming is more important on cartridges that headspace on the cartridge mouth. 9mm, 45acp, 40s&w for example. Check and trim as needed.

In other words always check and trim when over spec length.
Dallas Jack

 

[AF_Reloader]

I've have a digital micrometer and a CaseMaster Gauging tool, which is how I found the dozen or so that were 2.544.

I was curious if I need to trim the cases that are 2.536 when I trim the over-length ones as well, but I'm going with a yes on that one.

EDIT: The first time I load new or once fired brass I size and trim. I will generally trim to the length of the shortest brass in the bunch as long as it is in spec. I trim mainly to assure consistant in spec length. Check and trim as needed.

I was wondering about that as well (just trimming to the shortest case). I've got lots of brass, so I guess it's time to try out these different methods!

 

[WNTFW]

AF_Reloader,
I use the Lee pilot trimmer because they we cheap & I could decide what trimmer to get. The plus side of this is that the pilot is a fixed length & it is hard to over trim a case. (Too Short)

 

[kelbro]

I like to get them all the same length to start. That has to be tied to the shortest one. Especially if you plan to crimp with a regular seating die. I scrap brass when it requires a 3rd trimming.

If you purchase a Sinclair chamber length gauge, you will find that most factory barrels are very generous in the chamber length and you may never NEED to trim.

 

[qajaq59]

The more consistency you can attain in every stage of loading the better accuracy you'll have.