Building a 16" M14 for research. What bullet and powder for 1:10"?

[tonyben]

I'm building a 16" M14 for myself in an attempt to make an accurate SOCOM 16. The rifle will be built on a Bula Forge receiver with mostly GI parts, a unitized gas cylinder, a Criterion 16" barrel and will be cut with an M852 Manson chamber reamer. I will start off with a Springfield Armory SOCOM 16 gas lock muzzle brake.

I will eventually switch out the muzzle brake to a Delta-P SOCOM adapter and add a SureFire Muzzle brake.

I will be experimenting with a GI fiberglass stock, a JAE chassis, SAGE chassis, Blackfeather chassis, an AG composites carbon fiber stock (bedded) and a bedded Big Red Birch stock.

Scope mount will be a Sadlak Airborne mount.

I have never loaded for the 308 in 16" before. All the loads I have are for 22" barrels.

I am asking for your pet loads for 16" specific barrels that are accurate and efficient. I don't want to burn excess powder that's not needed. I have the current powders on hand:

-8208 XBR
-IMR 3031
-Varget
-RL 15
-IMR 4064
-IMR 4895
-H4895
-W748
-H335

Available Bullets:
-125gr TNT's
-168gr Nosler CC
-175gr Nosler CC
-155gr Berger Hybrids
-168gr Berger Hybrids

The hard part about these rifles is that I don't think anyone knows a good load for them. Once I have a good load, then I can tune the rifle. I did manage to dial one down to 1.3" for a customer after a few range trips and a bedding job. He reported back that the rifle "exceeded his expectations."

Few have really tried to match condition these but I feel its something I need to learn.

Short range (<300yds) and medium range (<600yds) loads are appreciated.

Thanks for your assistance.

Tony.

 

[10XSHOOTER]

You might want to try the TROY chassis stock. I love mine!
Also try 42.0 grs of IMR 4064 with either a 168 or 175 of your choice. We shot that load in the Navy M-14's 22" barrels though.

 

[Bart B.]

155's over 44 to 45 grains of imr4895 may be best. Velocity will probably be at least 100 fps slower compared to a 22 inch barrel with normal safe pressures.

 

[tonyben]

What brass and primers? I’ve got tons of lake city and CCI #34’s.

As far as pressures go, I’ll be using a Schuster adjustable gas plug to make sure I’m not overworking the action.

Tony.

 

[Nature Boy]

Nice to see you here @tonyben

 

[Zero333]

I just loaded up 40.5 & 41.5 gr of H-4895 under 168 smk 168amax or 168 Horn.BTHP.

H-4895 is nice and smooth working the action.

 

[rammac]

Hey Tony, nice to see you. I've got a couple of really good SOCOM loads that hold 1 MOA (plus or minus a couple tenths of an inch) at 100 yards. I've got one load that works pretty well in both my Loaded model and the SOCOM.

Looking at my notes it seems that I've had my best performance with 40.5 grains of IMR 3031 and 155gr bullets (I've had similar results with the Barnes TTSX and the Hornady A-Max).

I've also had nice results with 43gr of IMR 4166 under a 168gr Barnes TTSX.

RAMMAC

 

[tonyben]

Anyone know the upper end of my charge of IMR-3031 for the 125gr TNT's before I'm just wasting powder with the 16" barrel?

What about 4895 or 8208 XBR?

Will be using LC cases and Remington 9-1/2 primers or CCI-200's

I'd also like the same data for 110's and 135's.

Thanks,

Tony.

 

[tonyben]

Hey Tony, nice to see you. I've got a couple of really good SOCOM loads that hold 1 MOA (plus or minus a couple tenths of an inch) at 100 yards. I've got one load that works pretty well in both my Loaded model and the SOCOM.

Looking at my notes it seems that I've had my best performance with 40.5 grains of IMR 3031 and 155gr bullets (I've had similar results with the Barnes TTSX and the Hornady A-Max).

I've also had nice results with 43gr of IMR 4166 under a 168gr Barnes TTSX.

RAMMAC

Good yo see you too! I've got some 155gr Berger Hybrids. Do you think this load would work with this bullet?

Tony.

 

[tonyben]

As an update to this thread, I did build this rifle and I already test fired it. Held right around 1.1" at 100 after barrel break-in.

I built this off a James River Armory marked receiver, GI trigger group, op-rod, bolt and unitized welded gas cylinder.

I used a Criterion barrel from Fulton Armory, a Sadlak Airborne mount and a carbon graphite kevlar stock (hueygunner). Also used a reclaimed SAI SOCOM gas lock and a vented hand guard.

Tony.

 

[Zero333]

Whatever bullets and powders work best for the standard 21" barrel will work just as good on a 16" barrel.

The only thing that might be worth considering is some powders will give you less muzzle flash than others.

 

[Bamban]

I'd also like the same data for 110's and 135's.

Thanks,

Tony.

Tony,

I shot a few Ks of 110 V Max behind 44 grains of 8208, many rapid cleans. The best load I ever shot in matches were the 135 Berger flat base with 44 grains of 4064, 200-17 on MR 52, twice. Needed a long drop tube to pack those mini logs in the case.

These should work in that carbine length 14.

 

[mic2377]

Anyone know the upper end of my charge of IMR-3031 for the 125gr TNT's before I'm just wasting powder with the 16" barrel?

What about 4895 or 8208 XBR?

Will be using LC cases and Remington 9-1/2 primers or CCI-200's

I'd also like the same data for 110's and 135's.

Thanks,

Tony.

I have always liked H4895 in semi 308's. An ideal burn rate for gas guns, and forgiving in terms of node.

Watch your brass volume though. With LC brass I have had to drop charge weights significantly. I tried running up to 44+ grains under 150 grain class bullets in LC cases and primers were WAY flat with a nasty ejector swipe.

My favorite mild blasting load is 41.6-41.8 grains of H4895, LC brass, CCI-200, and whatever 155 grain match bullet I can get. It is very mild and makes 2575 fps out of an 18" barrel. It shoots well in pretty much every 308 gas gun and I have gotten 8-10 loadings out the brass depending on the gun.

Other light bullet loadings also work well and for those I much agree with 8208 XBR as a solid choice. I have also used H335, which works, but has a huge muzzle flash and is temperature sensitive.

 

[mic2377]

Also compliments on a sweet little blaster. I primarily shoot AR's mainly due to ease of assembly and tuning, but I would love to have a well-built M1a/M14 like that.

 

[tonyben]

got a proper scope for it. A Vortex Razor HD GEN II E 1-6x24/ MOA

This scope is definitely next level! It's all business.

Tony.

 

[mic2377]

Excellent choice on scope too. Couldn't pick a better one for a 16" mid-range 308. Great glass, super flat at 1x, and a nice and bright red dot. The reticle is ideal too for rapid 0-500 yard use.