Load for 18" AR-10

[birdus]

Got a new 18" AR-10 recently. While shooting the gun I can't tell, but I'm told there's a serious ball of flame coming out the end. So far, I've just used off the shelf target ammo (just cheap stuff). I'm guessing the main producer of muzzle flash is unburned powder after the bullet has left the muzzle. Seems like the obvious solution would be to use a faster burning powder so that by the time the bullet leaves the muzzle, the power has all burned, or very nearly all of it. Is that correct? Does faster burning powder give higher pressures? I have never done hand loading, but am about to begin.

Affirmation of my inferences or an explanation to the contrary would be greatly appreciated. Also, any suggested loads would be great.

Thanks,
Jay

 

[rcmodel]

No, it's not correct.

Your rifles gas system is tuned for standard burn rate powders used in the 7.62 NATO/.308 Winchester caliber.

The flash is not unburned power.
It is super heated gas coming out of the short barrel still at high pressure, and reacting with free oxygen in the cool air.

Your reloading powder and charge weight should be one of the middle of the road powders listed in any published reloading manual.

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

Muzzle flash & blast is just the price you have to pay with a short barrel.


BTW: Off the shelf "cheap stuff" uses the cheapest powder available to the manufacture.
Higher grade ammo, GI surplus ammo, and some reloading powders will have flash suppressant added and that will make a less noticeable ball of fire.

rc

 

[birdus]

Wow! I was way off! Very interesting. Thank you for the info.

 

[Roadkill]

any suggested loads would be great.

I use 44g of WC844 and a 150g bullet. Works well in my FALs and LR308.

 

[griff383]

The only time I ever saw a fireball in my 18" LR308 was when I used Winchester 147gr white box. Cabelas had it on sale for $8 or $9 a box so I bought a few boxes, after shooting a few rounds I decided to pull the rest and change powders.

 

[MachIVshooter]

I use 44g of WC844 and a 150g bullet. Works well in my FALs and LR308.

That's a pretty stiff load if you're using military brass. I run 41.5 Grs., 150's average 2,550 FPS from my 16" AR-10.