Trimming for Accuracy

[Graham Smith]

I see that trimming has been discussed here before but this is a bit of a different take on it. I'm new to reloading and find that the wealth of (sometimes conflicting and inaccurate) information on the internet can be a real problem.

For example, when it comes to the issue of trimming pistol cartridges (I currently only shoot 9mm luger) most books say measure and trim as needed, while most reloaders say don't bother.

But I have also found some sources that contend that finding the proper case length so that the cartridge will headspace properly in an autoloader can significantly improve accuracy. And that routinely trimming to that length will really pay off in smaller groups.

Has anyone had any experience with this?

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Secondly, if routine trimming is to be done, I'm assuming that loading then becomes a three stage process with a progressive loader.

1. Run the brass through to size and deprime, but nothing more.

2. Inspect, measure and trim the brass.

3. Run the brass back through the loader for the full process.

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Lastly, if I'm really going to bother with all this, what's the best trimmer for the job without spending another fortune on yet more equipment?

[AlamoShooter]

IF... You were shooting somthing like a singal shot Continder with a custom fixed barrel and a long range scope. And shooting off a good rest. And you could read the wind realy good. ? you may be able to tell the differenc at 75+ yards.

I used to run a "flash hole uniformer" in my 40 cal. brass that I shot at 35 yards. and yes I even cut a test set of 200 to all the same size. The group size may have changed by 1/4", ?

If you do trim 9mm casses keep it to your self = as you will get lots of snickers from other shooters

[sargenv]

I've never really trimmed a pistol cartridge for accuracy. Back when I was shooting a lot of 357 magnum ammo, I found that after only a few firings, you'd have to trim the 357 brass or it would not chamber. But after trimming it back, I usually did not have to trim it again before I either lost it or it cracked on me. Rifle cartridges are a bit different and depending on the loading/caliber, you may have to trim them a little more often. I've never trimmed 9mm or other short cases mostly because they just don't stretch all that much. While 9mm and 40 S&W are somewhat pressure intense calibers, they are nowhere near as intense as a 357 magnum or a rifle cartridge. You will probably not notice any difference unless you are shooting at extended ranges for a handgun, like Alamo Shooter said, TC contender or a test barrel @ 75 yards plus. At common handgun distances, it's more a factor of the gun and shooter than the ammo. When you get out past 100 yards, it can start being the gun, the shooter, AND the ammo.

[GentlemanJim]

Bottle neck rifle cases will GROW and need to be trimmed.

My experiance with pistol ammo is that cases tend to shrink (9mm,super)

I think only a bench rest shooter would pay that level of attention to his brass for pistol

Mine is worn out or lost way before that point.

Jim

[Graham Smith]

Thanks to all. As I said, there is a lot of poor information out there and I think that some people with way too much time on their hands are responsible for a lot of it.

After reading some of the other posts here, I decided to sign up and ask the question as it looked like I would most likely get a straight answer. I did hedge my bets a bit as I just rented a copy of Competition Reloading by Brian Enos to see if he said anything about it. I'm betting the answer is no.