Question about case trimming

[WyoGunner]

I am not quite sure about when I need to trim cases. My Lyman manual says cases stretch ect. and they may need to be trimmed. For .357mag they say that the case trim to length is 1.280". I measured a few of my 3 time reloaded cases and most of them are shorter than that. I have some that are even at 1.270". I would like to get my cases the same length so that I can reload them without having to worry about variances in how bullets are seated. Can I trim all of my cases to 1.270"? How short is too short? What do you guys recommend? Thanks.

 

[Cherokee]

Straight wall cases like 357M, 38 Spl etc don't usually stretch, whereas bottle neck rifle cases do. The only reason to trim straight wall cases is to achiever a uniform crimp. I would sort them by length and only trim the ones that are way longer than the majority of your cases if you want to do that. The unusually short ones you can load as a separate batch. However, I have never found it to make much difference unless you are a very good shooter and you are shooting accuracy matches. Some of my most accurate loads use mixed cases and mixed length. You could trim all the cases to 1.27, no harm, just a lot of effort for, in my opinion, little benefit.

 

[eric conrad]

+1 with what Cherokee said and be sure to resize before you measure them. Eric

 

[Will Farr]

Everything Cherokee said is exactly right. I have never trimmed a straight wall pistol case and have had no problems because of not doing so. Big waste of time and energy.

 

[Jimbo357mag]

If you want good consistent crimps, on say heavy loads or copper plated bullets where there are no crimp groves, it is a good idea to trim for length because it is the length of a shell in comparison to the others that determines the amount of crimp. I do all my shells the first time I load them and then again after about 5 re-loadings. After that they go into the moderate loading bucket for less than max loading. I also sort all my brass by headstamp and I color code so I can tell how many times a shell has been reloaded. Is any of this really necessary? hmmmm... I think it helps or I wouldn't do it.

...Jimbo

 

[buck460XVR]

With magnum powders like H110/W296, you need a firm consistent crimp for consistent ignition and best accuracy. Only way to assure this is to have every case in the batch the same length. For .357 mag and .44 mag I generally will trim new virgin brass or once fired factory brass after the first sizing for hunting loads using those types of powder. After three or four loadings at true magnum velocities, that brass goes for plinkin' loads and never gets trimmed again. The powders I use for those do not seem as sensitive of the crimp, nor is the small increase in accuracy realized. I do the same for .460 S&W, but will generally trim every other loading as it tends to grow quite a bit and not always evenly. I never trim .45acp brass.

 

[WyoGunner]

Next question, do you guys trim before or after you resize?

 

[contender]

After you resize!

 

[MADISON]

I have 2 ideas for your onsideration:
LYMAN makes a case length gage that sells for about $15.00.
The LEE trimming system trims cases to the correct length.

 

[Rick Courtright]

Hi,

I size, trim and chamfer all my new revolver brass (includes "new to me" scrounged stuff.) Only auto I load for is 9mm, which gets sized and chamfered, but not trimmed.

I know many don't go to the trouble of trimming revolver brass. Admittedly, I've wasted lots of time and energy on things over the years, but I don't consider this to be one of those times. I've had a couple of experiences w/ a certain "highly recommended" name brass that reinforce the thought.

Seldom does my revolver brass stretch enough to require a second trimming when using light to medium loads. I don't load enough full house stuff to advise anything but "measure and decide" for those who do.

Using the Lee trimmers, one gets "minimum" length automatically. Works for me.

Rick C

 

[pvtschultz]

Like Rick, I trim all new and new to me straight walled brass and sort any that are too short to be trimmed for separate loadings (light practice loads). After that, I really don't bother, but I don't shoot a lot of uber-heavy loads.

I trim rifle brass after each firing. I don't shoot competition, but like to pretend on occasion.

 

[Driftwood Johnson]

Howdy

Like you, when I first started reloading, I thought I needed to trim my cases. I even bought a used Lyman case trimmer. Then I started measuring my cases and found out that they were not stretching at all. A whole lot of years have gone by and I have never trimmed a single straight walled pistol case. Gotta get that silly trimmer off my loading bench, it is using up valuable real estate.

The general idea is that the manuals will give you a Max length for cases. Once your cases stretch beyond that limit, you are supposed to trim them to the 'Trim To' length, which is usually .005 or .010 less than the Max length, depending on the manual. Pretty tough to trim them back if they have not stretched in the first place.

If you want to trim them all to some artificial length, that's up to you. Personally, I have never bothered.

I also don't clean out primer pockets.

 

[Greebe]

Unless you are loading very hot loads in bottle neck cases they shouldn't stretch much. Like everyone else said the straight walled cases shouldn't need trimming.

The only reason for trimming the cases is so they don't bind in the chamber from the extra length. If they are under not harm no foul.

Greebe

 

[GP100man]

I`ve trimmed 50 peices to 1.180 to accomadate a longer boolit & worked up a load that works .

 

[AZBru88]

I do have to trim my 44 mag brass after 4-5 times shooting it in my TC or Desert Eagle (super hot loads). Its that time again unfortunately! Have about 4500 pieces to process. Lots of work ahead!
My other pistols I never have to trim! 9mm, 38 spec., 357mag But I don't load them super hot either!

 

[flatgate]

I routinely shoot "Ruger Only" loads in my Blackhawks and loads that are significantly "hotter" in my F-A .454. I do indeed see the need to trim once in a while since the crimps will NOT be uniform unless the cases are a uniform length.

I crono'd a .454 load yesterday. 335 grains at 1572 fps. A firm crimp is needed to prevent bullet "jump".

flatgate