.308 subsonic loads using 175 SMK's and Trail Boss, what OAL to load to?

[bhart89]

I'm loading up some 175 SMK's over Trail Boss. I'm loading 10 rounds of 11.5, 11.0, 10.5, 10.0 and 9.5 grains which I'll be using to test velocity and stability in my 20" 700 AAC with 1x10 twist.

I'm shooting for 1050-1100 fps.

Anyone know what OAL I should be loading to?

I normally load my .308 to 2.805"

Even with Trail Boss the 11.5 grain load doesn't fill the case.

I'm using standard large rifle primers with an unmodified flash hole.

 

[methos12]

Are you trying to compress the load? I did a 175 sub load for my .308 from 9.5-10.5 grains of Trail Boss and did spec OAL. I did 5 each in 0.1 grain increments. Federal 210M primers. I use a flash hole deburring tool to uniform the flash holes but otherwise leave the diameter alone. All of them fired just fine. I then did another 50 for plinking (10 grains even) and didn't have a squib among them. I think you'd suffer more from pulling too far back from the lands than getting a dud or two every 1000 rounds.

 

[The Zebra]

I use TB under 175 SMK's as well and my seating depth is 2.750". The powder doesn't even come close to filling the case and I do not have a problem with regular CCI large rifle primers.

 

[bhart89]

Here's some data from my range trip this morning.