338 lapua has a maximum case length. Is the chamber identical from gun to gun? I doubt it. so does anyone have a tip on getting the exact case length that works best for your own gun to have the best accuracy.( or am I just over reacting) . I tried chambering a case that was +.010 over max. length and it seemed to chamber smooth with no hesitation. Any suggestion from the experienced target shooters out there would be appreciated
case trimming for benchrest
- Thread starter tac-driver
- Start date
Johnn Peterson
CGN Ultra frequent flyer
- Location
- Chemainus B.C.
Stick to the posted case length's. The case length from gun to gun may not be exact so I take the 'stated' length as a set standard. After I resize, if the case length is at the maximum, I trim to 0.005"-0.010" less than the posted length. If you want to minimize the freebore & your magazine length will allow it, go for it. That's what I do & it seems to help accuracy, for me.
I'm not a bench rest shooter but do target (for fun) shoot quite a little bit and what I use to prevent over trimming is chamber length gauges.
The ones I have are made by Sinclair and can be ordered through them.
You take a full length sized case and trim it .100" shorter than minimum trim length for that calibre,drill a larger hole in the primer pocket so you can remove length gauge afterward.Insert the gauge into shortened case,seat it .100" longer than minimum trim length with a seating die,then insert it into the rifle chamber and close the action.Remove it,measure it and you now have your chamber's true length.
I have at least 2 rifle's that are over .030" longer than published max case lengths and therefore only will trim when brass gets to within about .024" of the actual chamber length.
You should go to their website and request a catalogue for reference at very least.They will quite likely send it to you automatically as they do me when every new issue comes out. their address is: www.sinclairintl.com
Check it out!
The ones I have are made by Sinclair and can be ordered through them.
You take a full length sized case and trim it .100" shorter than minimum trim length for that calibre,drill a larger hole in the primer pocket so you can remove length gauge afterward.Insert the gauge into shortened case,seat it .100" longer than minimum trim length with a seating die,then insert it into the rifle chamber and close the action.Remove it,measure it and you now have your chamber's true length.
I have at least 2 rifle's that are over .030" longer than published max case lengths and therefore only will trim when brass gets to within about .024" of the actual chamber length.
You should go to their website and request a catalogue for reference at very least.They will quite likely send it to you automatically as they do me when every new issue comes out. their address is: www.sinclairintl.com
Check it out!
"...Is the chamber identical from gun to gun?..." Nope. They'll all be slightly different due to tool wear, manufacturing tolerance, etc. The only way to get an exact chamber measurement is to make a chamber cast with Cerrosafe and measure it. Mind you, you're not going to be shooting benchrest competitions with a .338 Lapua. Shooting off a bench isn't the same thing as benchrest shooting.
In any case, having the case match the chamber isn't as important to accuracy as having cases all the same length. OAL of a loaded round can and does. Usually, loading the ammo so the bullet is just off the lands is best in most rifles.
In any case, having the case match the chamber isn't as important to accuracy as having cases all the same length. OAL of a loaded round can and does. Usually, loading the ammo so the bullet is just off the lands is best in most rifles.
