.308 169gr BTHP

[rskibo]

I bought some of the new 169s from Sierra. I’m loading with IMR 4064 loading to 2.800 which ends up at 2.150 BTO. As you can see the recommend starting at 43gr. However as I seat the bullet I can hear it crunching the powder. I backed it off to 42gr and still the same thing. I busted open a Federal GM 168 and the powder was clearly different, (which I expected) and wt was 40.7gr. Would the compressed load concern you? Thought?

 

[nn8734]

Im running 43.1g of 4064 in my Rem PSS using fed COTS brass. Im jumping .192 into the lands and my CBTO is identical to yours. I have zero pressure signs and shoots accurately, believe it or not.

MV is 2730 on average out of the stock Remington 24” barrel.

 

[rskibo]

Im running 43.1g of 4064 in my Rem PSS using fed COTS brass. Im jumping .192 into the lands and my CBTO is identical to yours. I have zero pressure signs and shoots accurately, believe it or not.

MV is 2730 on average out of the stock Remington 24” barrel.

Are you getting the compression? And I’ll be running these out of a AR platform.

 

[nn8734]

Are you getting the compression? And I’ll be running these out of a AR platform.

I hear crunching, whether its truely a compressed load, im not sure. But even if it is, im below the overpressure threshold.

For an AR10, id start at 41g (40.5 or so if suppressed) and work up in .3g increments as semis arent nearly as pressure tolerant in most cases.

 

[rskibo]

I hear crunching, whether its truely a compressed load, im not sure. But even if it is, im below the overpressure threshold.

For an AR10, id start at 41g (40.5 or so if suppressed) and work up in .3g increments as semis arent nearly as pressure tolerant in most cases.

Sound advice. Thanks. I will start there and work up. It’s a 20in barrel Sig DMR.

 

[nn8734]

Sound advice. Thanks. I will start there and work up. It’s a 20in barrel Sig DMR.

You’re welcome, you will like the 169.

Feel fee to check out my load dev thread using it in my mk11. Note that IMR4064 is a little faster burning compared to Varget, which is what i used in that work up

Mk11 Mod 0 Load Development and Testing - 169g Sierra Matchking

Had a chance to load up and test the new 169SMK in my Mk 11 Mod 0. Overall, I like the 308 but found the 175SMK to be lacking consistency beyond 700m (that’s after I factor me as an average shooter out of the equation). I developed a few quick loads using Sierra’s new 169 Matchking and tested...

www.snipershide.com

 

[B y r o n]

Are you using Winchester cases as indicated in the load data or are you using a different case with a smaller capacity?

 

[rskibo]

Are you using Winchester cases as indicated in the load data or are you using a different case with a smaller capacity?

I’m using once fired Federal brass.

 

[B y r o n]

I’m using once fired Federal brass.

Federal brass has less internal space than Winchester. Normally you have to drop the charge when using cases with less internal capacity.

 

[rskibo]

Federal brass has less internal space than Winchester. Normally you have to drop the charge when using cases with less internal capacity.

Thanks. I’m going to start at 40gr and work up.

 

[Doom]

~43 gr in Fed Brass was the 4064 FGMM 168 SMK load a while back. Several looks at the 40.x by several people has yet to clearly identify the powder. It’s not unusual to have compressed loads with 4064.

EDIT: Best guess on 40.x loads for FGMM was AR-Comp.