The more I read on this, the more confused I am; How often to actually trim?

[TheGerman]

Everywhere I've looked I've read something different. Trim every time you load, only trim when your round is over the max length, trim every X loadings,......

So which is it? For starters, I have two different sets of loading I do. One is for precision rifle where I want to be as accurate as humanly possible for bolt a bolt and semi, and then my practice/defense rounds for my AR carbine that I train with but am not needing to break any records as most of the shooting is done on the run or in a way that the added accuracy won't be seen.

Let's say I have virgin brass and it's trimmed to the perfect length for my chamber (or a generic start length). I shoot it once, resize it, and it's obviously grown but not over the max spec. When I measure the other rounds I shot in the same range session through the same rifle, I notice that they now all vary in length after firing which would now effect the cartridge OAL. What do you do?

 

[Ring]

bolt gun or AR?
in a bolt, i only neck size, and if u use a lee collet die, the brass never grows till you need to FL it

in a semi, u need to FL ever time, then i only trim when i hit max, i do not taper crimp, i use a factory crimp die, so case length dont affect neck tension

if you FL ever time in a semi, it may hit max after 4 or 6 shots... in a bolt u may get a few extra

 

[BuzzBoss915]

There are several different gauges available but you should get a feel for how much your case has stretched over X number of reloads. It's almost never every cycle and in some cases, never. I load for several Ackleys and because of the 40deg shoulder they never need trimming to length. Yes, as in NEVER.

But get a device to measure your chamber(s) and go from there, if you are that concerned. Check over all length AFTER resizing. BB

 

[milo 2.0]

When I measure the other rounds I shot in the same range session through the same rifle, I notice that they now all vary in length after firing which would now effect the cartridge OAL. What do you do?

Not really, just the case lengths are different, if you haven't changed the seating die settings, COAL should remain the same.
Neck tension MAY be slightly diff, but I doubt it.

 

[KelsonAK]

I trim every time. I don't use one of those old school hand crank trimmers - a WFT in a drill makes quick work of it - and I'm a believer in doing the same thing every time to get the same results. Do I HAVE to trim every time? Hell no, but I can spare the extra 5 minutes.

 

[Fuzzball]

It's much easier than you seem to think; when your cases exceed max length, trim them.

Trim-to-lenght is only a rational a suggestion, always 10 thou less than max. If you think trimming each time to keep your cases more helpfully "precise", do it. One thing for sure, case length variations don't affect the seating die setting so it won't change OAL.

 

[Dogtown]

It's much easier than you seem to think; when your cases exceed max length, trim them.

Ding! Ding! Ding!

And just so you know, the reason for this is that if the length is too long, when the brass starts expanding during firing, the edge of the neck will have nowhere to go and deform inward, crimping the bullet instead. This can create excessive pressures in the chamber and well, you know the rest.

You want your brass to be uniform and you'll probably not have to trim them after the first firing, but check anyway and expect to trim them every firing after that.

 

[kansas]

I trim every time whether it is for my LR rifle or my AR. My AR brass is usually picked up after a match and I have no idea whose brass I'm getting. Doesn't take very long with a Worlds finest trimmer. Saves the barrel. A lot of the brass I've picked up over the years has stretched way past max length.
For precision I do it...because I always have.

 

[thrusty]

I trim after each FL sizing. Using a Forester hand trimmer for most things and a WFT for the 6.5 Creedmoor. Will probably be getting a WFT for all my other calibers at some point....

 

[damoncali]

The reason we trim is to keep the case neck from jamming into the freebore, crimping the bullet and causing all manner of problem. Trim as often as necessary to keep that from happening.

 

[Sniper Uncle]

Everywhere I've looked I've read something different. Trim every time you load, only trim when your round is over the max length, trim every X loadings,......

So which is it? For starters, I have two different sets of loading I do. One is for precision rifle where I want to be as accurate as humanly possible for bolt a bolt and semi, and then my practice/defense rounds for my AR carbine that I train with but am not needing to break any records as most of the shooting is done on the run or in a way that the added accuracy won't be seen.

Let's say I have virgin brass and it's trimmed to the perfect length for my chamber (or a generic start length). I shoot it once, resize it, and it's obviously grown but not over the max spec. When I measure the other rounds I shot in the same range session through the same rifle, I notice that they now all vary in length after firing which would now effect the cartridge OAL. What do you do?

How do you figure that will affect COAL measurement???? The COAL is measured on the bullet tip, which is independent of the case length. Ogive length is better measurement, but this too is not dependent on the case length.

 

[thrusty]

How do you figure that will affect COAL measurement???? The COAL is measured on the bullet tip, which is independent of the case length. Ogive length is better measurement, but this too is not dependent on the case length.

+1 That's why you get paid the big bucks Uncle!

 

[BuzzBoss915]

I trim every time whether it is for my LR rifle or my AR. My AR brass is usually picked up after a match and I have no idea whose brass I'm getting. Doesn't take very long with a Worlds finest trimmer. Saves the barrel. A lot of the brass I've picked up over the years has stretched way past max length.
For precision I do it...because I always have.

For precision, huh? Pick up brass certainly won't help accuracy, Amigo. You are swimming upstream. Trimming to length is required when you have such an assortment of range brass and only indirectly helps "precision" by preventing the crimping upon seating the bullet caused by the too long necks. All I can say is, to be charitable; it can't hurt. Maybe. BB

 

[justinbaker]

The only way to know for sure is to get a chamber length gauge from Sinclair.

There was so much room in my stock Remington 700, that I doubt I will ever have to trim.

 

[kansas]

For precision, huh? Pick up brass certainly won't help accuracy, Amigo. You are swimming upstream. Trimming to length is required when you have such an assortment of range brass and only indirectly helps "precision" by preventing the crimping upon seating the bullet caused by the too long necks. All I can say is, to be charitable; it can't hurt. Maybe. BB

The reason that my range brass is mixed is because at most 3gun matches they don't want you to slow down the match by picking up your own brass during the match. We usually go back and pick it up at the end. For 3gun using 55 gr fmjs best that I can do is 3-4" at 100 yards. Plenty good for hoser stages. For the long range portion I sort out the Winchester or Remington brass and load with 69 gr SMKs and that gets me under 2" at 200 yards (good enough for the long range portion of most 3gun matches). The biggest reason I trim AR brass is for safety.
Now for my .308 I use Lapua and trim every time just because that's the way I started doing it. There ain't no reason to use expensive brass for 3gun, at least the hoser stages. For my long range rifle the only other brass that I've tried beside Lapua was FGMM. Wasn't pleased with FGMM.

But back on topic of when to trim, my point is it depends on what you're using it for and it's just as fast to stick it in the trimmer if you have something like a WFT as to measure each one with a caliper. In most cases you will find a lot of brass shot through a AR stretched a lot and has to be trimmed. If I was using brass for hunting and most shooting under 500 yards then I would trim it once and not worry about it for several loadings after that. For my long range matches I want everything to consistent so I trim every time. That's what works for me.

 

[timelinex]

Just buy the $7 chamber length measuring device from sincair and that will answer your question.

Both my savages have such long neck areas that I think the brass will be useless before I have to even think about trimming.