Do I need to trim my .38 brass after sizing it?

[country gent]

My 1911 wadcutter fun in 38spl will show a small difference in trimmed and untrimmed cases. It needs to be in the ransom rest but it does show it. LOL.

[samari46]

I trim all pistol and revolver brass wether it's new or range pickup. Buddy of mine did concealed carry classes so 99% of the brass was all new. fill up a bucket and go to it. I'd resize all the brass from new and what I picked up. Then trim it. This way all the crimps were in the same place. That range instructor used to let me do the sweeping for him. I have 1 40mm full of 38 special brass. Frank

[Three44s]

All my metallic loads get the inside flash hole deburring so I need a consistent length for the tool to index off of. So I trim.

The debur and the consistent crimping derived from trimming (also squares case mouths) gives me better ignition.

This debur lasts for the life of the case and thus far I have had no seconds on needing retrimmed for handgun loading.

Three44s

[Littlewolf]

agreement on straight wall pistol doesnt move (much) when firing which makes a second trimming not needed. BUT if you want a consistent bell to the mouth (IE if you load fat cast bullets and need the mouth wide open) a first trimming is helpfull. ive grown new grey hairs with 45colt and 9mm brass being in specs but different lengths causing the short side of the selection to not bell much and not letting the boolits pre-seat very well.

[Conditor22]

much of the factory handgun brass is mass-produced and not always true on the ends or even meet minimum Samii coal

[Alan in Vermont]

Maybe 3-4 years ago I started trimming my 38 brass. I found that 38 brass is all over the map as far a length is concerned. So I measured a mess of mine to establish the shortest length. I trimmed everything to 1.120" which cleans up all but a very small percentage which are already slightly under that. Yes it was a nuisance to trim them all but with a cordless drill on my RCBS trimmer along with the nifty little chamfering gadget they have for it it's easy enough and made a good winter project.

It's worth it to get uniform flares & crimps.

[Misery-Whip]

Ive never trimmed a straightwall either. For me this is 380, 9mm, 38special, 357, 45 auto.

[tankgunner59]

I too tried trimming some straight wall pistol brass, including 38 special and 357 magnum, years ago to improve accuracy. It didn't happen, accuracy improved as I got used to the individual guns. I have never trimmed that type of brass since. With below max powder charges it takes forever for these types of cases to stretch enough to notice.
BTW welcome to the community, you'll love it here!

[mvozz]

I never trimmed my 357 mag brass until I ended up with 1000 rounds of range brass. I couldn't get anywhere close to consistency on my crimps, also had some very short Hornady brass mixed in that were a pain and got culled. In frustration I measured until I found the shortest brass and trimmed them all to that length. I didn't need my crimps to be perfect but I did need something with a bit more consistency. After trimming and deburing I haven't touched them again. That has been several years ago and I haven't had a problem since.

[Engineer1911]

I have had 44 mag and 357 mag cases stuck in a cylinder because the case was too long. I trim that brass once and forget it. The cases developed mouth cracks before they need trimming a second time.

Twenty years ago I shot a S&W M52 in competition. I only shot military brass, trimmed it once for uniform crimp and all was good. 38 Spl brass will never be too long for a 357 mag cylinder so trimming isn't required, but it certainly helps for uniform crimping.

[JBinMN]

If ya feel like doing it & it would make ya feel better, then Just do it.


If not, forget about it.

[Andyt591]

Thanks guys! Y'all talked me out of trimming it.

[BrutalAB]

I trim all my 357 mag and 38 special brass once. Its for uniform crimps. I have found that these two cases only grow after the initial firing/resizing. I measured a 357 case on its 6th firing/resizing cycle and it was the same exact length as when i trimmed it.

I do most of my shooting out of a rifle though, so i treat it like rifle brass. Even uniform the primer pockets and sort by headstamp. Headstamp sorting and trimming for consistent crimp gave me noticable improvents. I havnt done comparrison between uniformed primer pockets or not. I just do it anyways at this point.

[gwpercle]

It all depends on your anal-OCD level , if you have a high level ... then yes , absolute perfection and consistency is required in everything .

If you have a low anal-ocd level then don't worry about it...there are only two things in life you have to do .

I trimmed a batch of 38 cases 40 years ago but have given up the practice for lack of any measurable increase in accuracy ... it's a waste of my time .

Test your anal level and trim accordingly ,
Gary