How often do you trim ,308 brass for a Bolt gun?

[ReaperDriver]

Lately I've been very anal about my brass prep and I've been trimming to the 2.005 trim length every time I load now. I've been noticing that even after being FL resized, none of this last batch of Lapua brass (fired about 5-6 times) was longer than the max length. Should I bother trimming unless it exceeds max length or is it better to trim each time to keep consistency the same for evey range session?

As a collorary question - is the ultimate accuracy affected by slight differences in case length as long as they all are within the min-max length?

FYI - there have been no chambering issues and the gun is a factory Rem 700 SPS-T. Just wondering if I'm spending too much time trimming when I could be watching college football instead?

 

[Requiem]

Re: How often do you trim ,308 brass for a Bolt gun?

tagged.

 

[Buckoman]

Re: How often do you trim ,308 brass for a Bolt gun?

I had one guy say he would trim back .001 from max and then when it hit max then he'd throw em out. I think this was a waste personally.

I would say if they ALL are the same length then you don't need to trim. If not then go ahead n trim em. Consistency is the key

 

[Niles Coyote]

Re: How often do you trim ,308 brass for a Bolt gun?

Reaper,

It all depends on what you want to do. The key here, are all of your cases growing the same or are we talking some with different lengths within the same lot to be fired.

If you are shooting relatively short range (200y and under) where slight differences in pressure/velocity don’t show up on target much, I'd say don’t worry about trimming every time. Now if you are chasing low ES/SD or shooting 300y on out consistency in length can be a significant factor.

 

[ReaperDriver]

Re: How often do you trim ,308 brass for a Bolt gun?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Niles Coyote</div><div class="ubbcode-body">Reaper,

It all depends on what you want to do. The key here, are all of your cases growing the same or are we talking some with different lengths within the same lot to be fired.

If you are shooting relatively short range (200y and under) where slight differences in pressure/velocity don’t show up on target much, I'd say don’t worry about trimming every time. Now if you are chasing low ES/SD or shooting 300y on out consistency in length can be a significant factor.
</div></div>

I typically shoot 300-400yds min and out to 1K. In fact I'll be shooting at 1K on Wed in the desert (sweet). So that answers my question. I assumed it would make a difference at longer ranges, just interested if anyone was actually seeing it.

thanks.

 

[nicholst55]

Re: How often do you trim ,308 brass for a Bolt gun?

I spot check at least 10% of the brass in a given lot; if any of the sample exhibits excess length, I trim the entire lot. That said, you need to know the length of the chamber on each specific rifle, as they can vary a lot. On some rifles I run brass that is longer than SAAMI 'max,' because that particular chamber is also on the long side.

Tailoring the brass to the specific rifle will minimize bullet jump, and I believe it improves accuracy. It does complicate things, and I wouldn't recommend this for someone trying to feed multiple rifles of the same caliber. You have to segregate brass by rifle and keep meticulous records if this is going to provide any benefit.

 

[918v]

Re: How often do you trim ,308 brass for a Bolt gun?

My chamber accepts brass as long as 2.035". I trim every five firings or so.

 

[sobrbiker883]

Re: How often do you trim ,308 brass for a Bolt gun?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">
As a collorary question - is the ultimate accuracy affected by slight differences in case length as long as they all are within the min-max length? </div></div>

I don't think I can shoot the difference in .010" case length, so for now I don't sweat it.
I trim my 308 back to 2.005" and when they won't pass through calipers locked at 2.015" they get trimmed. My 7-08 is even easier, when I neck down 308 brass the cases are a lot shorter than 7-08 max, so much so that the primer pockets go prior to trimming. The last "uneven" 7-08's I chrono'd had an SD of 7......

 

[DMS]

Re: How often do you trim ,308 brass for a Bolt gun?

I trim every time. One less variable and doesn't take much time. However, I think slight variations in case length has very little effect on accuracy.

 

[jarheadkp]

Re: How often do you trim ,308 brass for a Bolt gun?

I trim every time I fired them. I have enough brass to last me for 2 year... so during the winter months, I have plenty of time to have available brass if I decide to change the load. The Giraud case trimmer makes trimming casings a breeze.

 

[MitchAlsup]

Re: How often do you trim ,308 brass for a Bolt gun?

I trim every time. I just chuck the cutter in my lathe, the holder in my hex wrench, then grab a case, press to lathe, remove case and repeat. It takes longer to place and remove the case on the holder than it does for the trimming.

 

[vinconco]

Re: How often do you trim ,308 brass for a Bolt gun?

How often you have to trim is directly related to how much you set the shoulder back during the resizing operation. Setting the shoulder back causes the brass to extrude making it longer. Set the sizing die to your chamber and you will not need to trim as often and the brass will last longer. Most chambers are longer than the listed max case length. Use the chamber gauge from Sinclair to measure your rifles chamber. Sinclair chamber length gauge

 

[MitchAlsup]

Re: How often do you trim ,308 brass for a Bolt gun?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vinconco</div><div class="ubbcode-body">How often you have to trim is directly related to how much you set the shoulder back during the resizing operation. Setting the shoulder back causes the brass to extrude making it longer. </div></div>

Mostly, I use neck-only sizing (assuming the RCBS case mic give the sholder position the 'thumbs up'), so mostly the neck length has not changed by more than 0.001, and about half the cases get trimmed and still have visible chamfer and deburr edges left.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Set the sizing die to your chamber and you will not need to trim as often and the brass will last longer. Most chambers are longer than the listed max case length. Use the chamber gauge from Sinclair to measure your rifles chamber. Sinclair chamber length gauge </div></div>

Even if you throat is long enough, everyone needs to remember that brass expands durring the firing process and pressure goes through the roof if the end of the case neck encounters the end of the throat and the brass is forced up and into the bullet. So even if you measure this, keep at least 0.005 and prefered 0.007 between end of case neck and end of throat to accomodate temperature differences and firing pressures.

 

[Victor N TN]

Re: How often do you trim ,308 brass for a Bolt gun?

For the bolt guns I have checked the chambers and have the CORRECT max length for that chamber. When I check the brass before loading it, I set my dial calipers for the max length. Then if the case slides through it, I don't trim. If it doesn't slide through, I trim.

 

[vinconco]

Re: How often do you trim ,308 brass for a Bolt gun?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mitchAlsup</div><div class="ubbcode-body">Mostly, I use neck-only sizing (assuming the RCBS case mic give the sholder position the 'thumbs up'), so mostly the neck length has not changed by more than 0.001, and about half the cases get trimmed and still have visible chamfer and deburr edges left </div></div>

I used to do the neck thing but since consistancy is the key I just cut to the chase and started using the Redding type S FL sizer w/ bushing and set the sizer to bump the shoulder a couple thousands and now all my ammo chambers the same and I manage to keep the "growth" down to a minimum. I don't have to check each piece so the process gets much easier.

 

[bdh308]

Re: How often do you trim ,308 brass for a Bolt gun?

Great tip Vinconco. +1 on the FL Redding bushing die. And I actually got that wonderful info from the man himself who has shit tons of experience loading accurate rifles...Victor.

 

[pistolpete75]

Re: How often do you trim ,308 brass for a Bolt gun?

Get the Giraud and the RCBS Trim Mate Case Prep Kit. These two tools have been super to me in the brass prep game. I trim, debur, champher, uniform pocket primers, and clean primer pockets in a jiffy. As life gets busier, I have less time to do reloading "chores". These two tools have saved me countless hours.

 

[okiefired]

Re: How often do you trim ,308 brass for a Bolt gun?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: nicholst55</div><div class="ubbcode-body">Tailoring the brass to the specific rifle will minimize bullet jump,</div></div>

How does brass length effect bullet jump when it dosnt effect OAL at all?

okie

 

[Victor N TN]

Re: How often do you trim ,308 brass for a Bolt gun?

How about the right length brass will save you maybe a few hundred rounds on the throat before accuracy starts dropping...?

 

[okiefired]

Re: How often do you trim ,308 brass for a Bolt gun?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">How about the right length brass will save you maybe a few hundred rounds on the throat before accuracy starts dropping...? </div></div>

Victor, if that was directed at me, you'll get no argumant there. I'd still like to know how brass length would effect bullet jump?

okie

 

[InTheWeeds]

Re: How often do you trim ,308 brass for a Bolt gun?

I also trim everytime. I noticed that my Rem and Win brass stretch about .003-.005 every shot with some hot loads. The nickel plated brass I reload doesnt stretch at all however

 

[Victor N TN]

Re: How often do you trim ,308 brass for a Bolt gun?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: okiefired</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">How about the right length brass will save you maybe a few hundred rounds on the throat before accuracy starts dropping...? </div></div>

Victor, if that was directed at me, you'll get no argumant there. I'd still like to know how brass length would effect bullet jump?

okie </div></div>

I guess I was just throwing it out for anyone that might want it. Unless someone knows something I don't, brass doesn't do that. The COAL or seating length controls that. And I know you know that. Again, I'm just throwing that out.

 

[ChrisGarrett]

Re: How often do you trim ,308 brass for a Bolt gun?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">Lately I've been very anal about my brass prep and I've been trimming to the 2.005 trim length every time I load now. I've been noticing that even after being FL resized, none of this last batch of Lapua brass (fired about 5-6 times) was longer than the max length. Should I bother trimming unless it exceeds max length or is it better to trim each time to keep consistency the same for evey range session?

As a collorary question - is the ultimate accuracy affected by slight differences in case length as long as they all are within the min-max length?

FYI - there have been no chambering issues and the gun is a factory Rem 700 SPS-T. Just wondering if I'm spending too much time trimming when I could be watching college football instead?

</div></div>

In my experience, if you're well (.005") under your chamber's 'max length' and all chambers vary in this measurement, then being a few thous longer or shorter in a batch of 50 won't wash out one's parade.

I don't trim to the minimum because I like my necks to be a bit longer in my personal chambers, so as to create a better gas seal. Ideally, all of my cases would be the same length, but I don't think that +/-.002 is going to show up on paper, but then again, I'm no expert.

I can let my cases get to 2.820+ in my factory Savage LE2b, so I'll let them grow to 2.815", or so, before I feel the need to trim.

Life's too short to worry about a few thousands of an inch.

Chris

 

[DaveV]

Re: How often do you trim ,308 brass for a Bolt gun?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body">Life's too short to worry about a few <span style="text-decoration: line-through">thousands of an </span>inch...es.</div></div>

I keep telling my wife this

 

[MoMopacksa45]

Re: How often do you trim ,308 brass for a Bolt gun?

I trim every time, but then I am annal about reloading. Couldn't tell you if it matters. but it makes me feel better.

Mike

 

[TOP PREDATOR]

Re: How often do you trim ,308 brass for a Bolt gun?

ditto, every time. my thouoghts are consistant accurraccy equals doing the same thing over and over and over.