16 inch .308 barrel powder recommendation

[Sb1911]

Just purchased a DPMS LR .308. It has a 16 inch barrel with a 1 in 10 twist rate. I will be using 168 grain a max mostly but also some Nosler 150 and 180 grain ballistic tips. I have also found some lake city long range non crimped brass that I will be ordering. My question is what powder should I use with such a short barrel? Anyone have any experience with this rifle or barrel length that could help? Any information would be greatly appreciated.
Thank you

 

[rcmodel]

Look at your reloading manual.

Whatever powder gives the highest velocity with a long barrel will also give the highest velocity with a short barrel.

You do not pick powder based on barrel length, as that has nothing to do with proper burn rate, gas port pressure in an AR-10, or anything else.

rc

 

[119er]

I landed on H335 in the same rifle with 18" barrel for a friend of mine. Lots of blast and that particular one was kind of a pain to make happy. We settled on a load for 200yd shots at deer and called it good. He wanted that ability w/o the blast. 41.5 gr H335 gave 2500's with little blast 42.0 and up was noticeable flash. That thing destroys his brass as well. It was once fired factory Remington Core-lokts and after the second firing you could tap the new primers out with a light tap on the benchtop. About half of the 60 or so cases did this.

 

[blarby]

Tagged for posterity. I'll be havin one of these soon myself, and would love the "masters notes"

 

[rcmodel]

That thing destroys his brass as well.

The gun isn't making loose primer pockets.

Excess pressure loads are.

You need to Back Off a little.

rc

 

[jaysouth]

Is that monster muzzle blast caused by a portion of powder igniting outside the barrel?

 

[rcmodel]

No.

Muzzle flash is super heated compressed gas coming in contact with oxygen in the air.

rc

 

[elwoodm]

i have a cetme with a 16 inch barrel no gas port and i run varget mainly in that one. no blazing velocity with that short barrel so i stick at 42 to 44gr with 150gr bullets just getting to 2500fps. the 168gr bullets run good with 42.5gr at 2400fps not much muzzle flash if you go with the H335 use mag primer just to be on the safe side had past problems with that powder not getting lit to good.

 

[critter]

I have both an M1A 16" and a Ruger compact in 16". I use IMR 4895 in both of them. I do not have a Chrono but accuracy has been really good and both have killed dear quite effectively. I am using 150 gr Nosler BT's in both and am not trying to wring the absolute highest velocity out of the guns.

 

[Sb1911]

Thanks for all the info so far, I'm going to get some 4895 and go from there. I figure is should be good for all my 150 and 168 grain bullets.

 

[jaysouth]

No.

Muzzle flash is super heated compressed gas coming in contact with oxygen in the air.

rc

Just curious, Why does a short barrel have more muzzle flash than a longer one?

In reloading clay target loads, a moderate charge of fast burning powder has almost no muzzle flash. The same shot load in the samd hull, same wad, same gun will produce a loud muzzle flash loaded with a slower powder.

Think red dot versus blue dot.

 

[rcmodel]

Because residual bore pressure is higher at the muzzle of a short barrel when it is released into the atmosphere.

Same with your shotgun powders.

Red Dot is much faster burning then Blue Dot.

So the slower powder maintains higher bore pressure longer in the same length barrel.
Which translates to higher remaining bore pressure at the muzzle.

rc

 

[CraigC]

There are so many misconceptions about what goes on before a bullet leaves the muzzle. Thanks to rcmodel for setting it all straight.

 

[119er]

The gun isn't making loose primer pockets.

Excess pressure loads are.

You need to Back Off a little.

While I won't argue that these are signs of excess pressure, I will say that I don't believe it is so in this case. 41.5gr of H335 is .5gr above the starting load and where we ended up. Is it the residual gas pressure at the time of unlock for the stretching of the brass or some other function of the cycling process?

This would also indicate that the factory loads were excessive as well because about 8 cases were culled for the same reason on the initial reload. Could be a soft brass lot. (Against my advise my friend insisted on using the cases, btw)

Could it be H335 causing it?

Is there still a possibility for excess pressure with such a load, bullet seated to magazine length, minimum charge and 85fps below starting velocity?

 

[rcmodel]

O.K. then.

You got some soft brass.

Unlocking or extraction cannot occur before chamber pressure has dropped way below what it takes to enlarge a primer pocket.

The whole case would blow and destroy the gun if it could due to unlocking too soon.

rc