.308 Brass Trim Question
- Thread starter kwak
- Start date
Re: .308 Brass Trim Question
Shoot it, it'll stretch back out...
Unless you are shooting light loads or have an extremely tight chamber.
Is this measurement coming from fired brass?
Shoot it, it'll stretch back out...
Unless you are shooting light loads or have an extremely tight chamber.
Is this measurement coming from fired brass?
Re: .308 Brass Trim Question
I believe that'll be unacceptable for 300 yard shooting, so why dont you just box it and send it to me.
lol It's fine, just go ahead and shoot it and it'll stretch out again.
I believe that'll be unacceptable for 300 yard shooting, so why dont you just box it and send it to me.
Re: .308 Brass Trim Question
The most important thing is that it's all the same length for uniform bullet tension. On your next reloading/trimming session you can correct your trimming operation.
The most important thing is that it's all the same length for uniform bullet tension. On your next reloading/trimming session you can correct your trimming operation.
Re: .308 Brass Trim Question
Should work great. Like stated before as long as it all the same length it will not effects accuracy. And you will be able to fix it later. Good luck
Should work great. Like stated before as long as it all the same length it will not effects accuracy. And you will be able to fix it later. Good luck
Re: .308 Brass Trim Question
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1696162#Post1696162
"Trim to length: upon firing of the loaded round the case greatly softens and inflates like a balloon to fill the chamber of the weapon. This seals the chamber and prevents gas leaks, etc. but with the brass nearing a liquid ("plastic") state it flows with the pressure of the propellant gas. Hence as stated before our primer pockets not staying uniform, the over all length of the case grows and the mouth of the case typically thins. Your reloading manual will give you the nominal "trim to length" measurement of a given cartridge case. So place said case in your case trimmer and trim it back correct? No.
NO!!! We are precision shooters for crying out loud. I have a friend that mows every case he get's his hands on back to minimum length and it gripes me to no end.
Historically & generally speaking the classic ultra accurate cartridges of the Bench Rest environment have longer than normal case necks. The typical case neck for a given cartridge is one caliber wide. Example: a .308 Winchester's bullet is a diameter of .308" so therefore the rule of thumb is the mouth of the case should be "about" .308" long minimum. This allows good bullet tension and support so our carefully assembled loaded round's bullet is sitting dead inline with the case's center-line --- which is inline with the center line of the bore. All this leads to good shooting and smiles. The more we hack back the case mouth the less neck we have to make sure our bullet is held inline. And the benchrest cartridges I mentioned- they have caliber plus neck lengths for this reason.
So what do we do? If the case gets too long, it will engage the rifling at the same time the bullet tries to giving us a wild & very dangerous pressure spike. If we hack it back to bare minimum we may have given room for a little loss of accuracy, especially with rough handling of ammo in the field. But we HAVE TO maintain consistency from case to case for shot to shot.
The answer is to measure the chamber length in your individual rifle and stay trimmed back from that actual number. Small chamber plugs to get that measurement are sold by Sinclair and others.
http://www.sinclairintl.com/product/11241/Case-Gauges-Headspace-Tools
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1696162#Post1696162
"Trim to length: upon firing of the loaded round the case greatly softens and inflates like a balloon to fill the chamber of the weapon. This seals the chamber and prevents gas leaks, etc. but with the brass nearing a liquid ("plastic") state it flows with the pressure of the propellant gas. Hence as stated before our primer pockets not staying uniform, the over all length of the case grows and the mouth of the case typically thins. Your reloading manual will give you the nominal "trim to length" measurement of a given cartridge case. So place said case in your case trimmer and trim it back correct? No.
NO!!! We are precision shooters for crying out loud. I have a friend that mows every case he get's his hands on back to minimum length and it gripes me to no end.
Historically & generally speaking the classic ultra accurate cartridges of the Bench Rest environment have longer than normal case necks. The typical case neck for a given cartridge is one caliber wide. Example: a .308 Winchester's bullet is a diameter of .308" so therefore the rule of thumb is the mouth of the case should be "about" .308" long minimum. This allows good bullet tension and support so our carefully assembled loaded round's bullet is sitting dead inline with the case's center-line --- which is inline with the center line of the bore. All this leads to good shooting and smiles. The more we hack back the case mouth the less neck we have to make sure our bullet is held inline. And the benchrest cartridges I mentioned- they have caliber plus neck lengths for this reason.
So what do we do? If the case gets too long, it will engage the rifling at the same time the bullet tries to giving us a wild & very dangerous pressure spike. If we hack it back to bare minimum we may have given room for a little loss of accuracy, especially with rough handling of ammo in the field. But we HAVE TO maintain consistency from case to case for shot to shot.
The answer is to measure the chamber length in your individual rifle and stay trimmed back from that actual number. Small chamber plugs to get that measurement are sold by Sinclair and others.
http://www.sinclairintl.com/product/11241/Case-Gauges-Headspace-Tools
Re: .308 Brass Trim Question
How far to trim back from where the leade starts? I actually just made a couple plugs up today out of a chunk of brass to measure my 308 and 338, my Savage 10 measured out at 2.041, I was thinking (if I ever even reach that length during the brass' lifetime) to trim them to 2.035, that should keep me safe no?
How far to trim back from where the leade starts? I actually just made a couple plugs up today out of a chunk of brass to measure my 308 and 338, my Savage 10 measured out at 2.041, I was thinking (if I ever even reach that length during the brass' lifetime) to trim them to 2.035, that should keep me safe no?
