Optimal case length for .308 in M1-A?

[Kosh75287]

I have 400+ Remington .308 Win brass that I'm prepping for use in my M1-A. I'm hoping that a veteran (High Master?) of long range rifle competition might advise me as to a good/better/best "trim to" length, when loading with 168 grain SMK. I don't know that the choice of powder will make much difference, but it'll most likely be H4895, WW748, or RL-15.

I'd like to try some Alliant RL-10X, but haven't found any. The nice thing about .308 is that almost any fast to medium rate rifle powder works at least "OKAY" in it. I'm inclined toward the faster end of the spectrum for economic considerations. On the other hand, if I find that 4064 or Varget shoots way WAY better than, say, H322 or H335, then I'll stick a crowbar in my wallet and buy a slower burning propellant.

Anyway, any input on the "trim to" length would be appreciated. Any input on the rest wouldn't hurt my feelings, either. Thanks in advance.

 

[1200 meters]

I load Sierra 175gr HPBT at 2.80 and they work wothout problem. You may want to check up on crimping your rounds that will be used in a magizine. Do make sure of your primer seating. (beware of Slam Fires) blitz
Sorry I didn't annswer your question. You should seat one of your bullets to about 2.80 OAL. then measure the seating depth you need and put that against the brass to be trimed. blitz

 

[rcmodel]

Trim-To length of the .308 Winchester is 2.005".

Max case length is 2.015".

rcmodel

 

[45ACPUSER]

I shot a lot HP with Fulton Armory M1A and I never crimped a round, and I shot a M1 Garand and never crimped a round! Consistency is one key to reloading! Eliminate the variables I always say. I shot a lot of IMR 4895 and IMR 4065 out M1A and M1 Garand respectively! If it aint broke do not fix it. The 168 or 175 OTM is probably best at COAL of 2.82".

 

[Kosh75287]

Okay, so if I'm reading this right, I should just keep the "trim-to" length somewhere between 2.005" and 2.105", but manipulate the seating depth for the c.o.a.l. what is less than 2.800" and gives the best accuracy?

And thank you all for the input. I really appreciate it. I'm just trying to make sure I'm understanding it correctly.

 

[rcmodel]

2.005" and 2.105",

NO!
2.005" min - 2.015" max.

2.105"would be a mite long!

rcmodel

 

[ocabj]

Stick with H4895. As far as your bullet, you might be better served with 155 or 168. I'd shy away from A-Max's in the M14. One of the junior shooters I know from the local matches had the tips come off some of his 155gr A-Max rounds during his rapid fire string.

Berger makes their 155 and 168s in both a standard BT or VLD form, and have incredible BC for 30cal. The 155gr Lapua Scenar is also highly regarded.

 

[Sunray]

Use the trim-to length given in your manual and don't forget to chamfer the inside of the case mouth and deburr the outside after trimming. 2.800" has worked just fine out of my real semi'd M14 for eons.
Loading for a semi auto only has one absolutely required step. Full length resizing every time. Other than that and watching the case length, it's no different than loading for any rifle.
"...find that 4064 or Varget shoots way WAY better..." Yep. The .308 loves those powders with 165 grain hunting bullets and 168 or 175 grain match bullets. 168's for up to 600 yards, the 175's past there.
As long as the case necks are sized properly, crimping isn't really necessary. Crimping is detrimental to accuracy any way.