Chamber length vs Trim length?

[Conqueror]

I have been reloading a long time but am getting into precision loading much more recently.

I am shooting a Sako TRG-22 and measure my chamber length at 2.04485" (well, that's an average of 10 measurements taken with a Sinclair chamber plug). Call the rounded mean 2.045", which was also the mode.

So, now what? Should I trim to exactly that length? 0.003" shorter? Is there any "conventional wisdom" on this?

Thanks.

 

[RotARy15]

Re: Chamber length vs Trim length?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Conqueror</div><div class="ubbcode-body">I have been reloading a long time but am getting into precision loading much more recently.

I am shooting a Sako TRG-22 and measure my chamber length at 2.04485" (well, that's an average of 10 measurements taken with a Sinclair chamber plug). Call the rounded mean 2.045", which was also the mode.

So, now what? Should I trim to exactly that length? 0.003" shorter? Is there any "conventional wisdom" on this?


Thanks. </div></div>

I believe conventional wisdom is .010 shorter.

 

[Trevor]

Re: Chamber length vs Trim length?

Safety wisdom is .010 brass can grow as much as .005 during a single firing and that close a tolerance can leave you with very unpleasant consequences..

 

[427Cobra]

Re: Chamber length vs Trim length?

Congrats to another person who used the correct tool to determine the trim length for there weapon, 2.005 is way to short, the instructions that came with my plug said trim .024 shorter, I questioned where in the world did .024 come from and never got a decent answer, I use .010, but I have custom chambers, and a Giraud trimmer, so trimming is no big deal, with a production chamber I would pick a number that is at least .010 shorter and stick with it, 2.010-2.020 should work fine, keep the necks square and a uniform length, YMMV.

 

[LR-WSM]

Re: Chamber length vs Trim length?

Just in case someone tries to look up a chamber plug and doesn't get the right item. <span style="color: #009900">HERE</span> is the item being used

 

[Muttt]

Re: Chamber length vs Trim length?

I have a question about this.

Do you label your ammo for that specific rifle? If you have more than one rifle that shoots that ammo, wouldn't you have to measure each one and then trim to the shortest one?

I think you guys get the idea of my question. Forgive me if this is a noob question. I always just trim to book length to keep things consistant.

 

[turbo54]

Re: Chamber length vs Trim length?

Any trim length that will disallow the casemouth from getting pinched in the throat will work fine. 2.005" will be fine, though no reason to go that short.

There is speculation that longer necks = longer throat life. Maybe that is true, but it matters not in a 308 anyway.

If you HATE trimming, I'd allow them to grow to 2.035" or so, then cut them back to 2.010" so that you're only trimming any given case once in its effective lifetime. If you're rocking a giraud and/or love to trim, 2.035-2.040" would be great.

 

[Conqueror]

Re: Chamber length vs Trim length?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Muttt</div><div class="ubbcode-body">Do you label your ammo for that specific rifle? If you have more than one rifle that shoots that ammo, wouldn't you have to measure each one and then trim to the shortest one?</div></div>
You can load for each specific rifle, or trim your cases to a "standard" length (ie, the kind recommended in load manuals) so they will work with everything you shoot.

In my case, I am loading for one particular rifle. Every box of reloads I make is labeled with the specifications of the ammo inside.

 

[Conqueror]

Re: Chamber length vs Trim length?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">Any trim length that will disallow the casemouth from getting pinched in the throat will work fine.</div></div>
I think this is the answer that will best work for me. I don't mind trimming more frequently and would rather have ammo that is tailored for the rifle and extremely consistent. Assuming a chamber length of 2.045" I will probably trim to something like 2.037" and trim on every firing.

 

[Jig Stick]

Re: Chamber length vs Trim length?

I shoot a 300winmag, BAT Action, Krieger barrel. I typically take virgin brass and trim it to the length noted in my Lyman book. Then I shoot them and reload them, annealing them every 3 firings. I dont trim them until I get problems seating them. When I come across a piece of brass that causes a problem, I measure it, and trim 0.010 off. And then shoot until they have problems again, etc...and repeat repeat repeat. Only trim when you get a problem. Your brass will last a long time this way.