What size bullet for a 1:8 twist?

[skywalkrNCSU]

I recently built a precision based AR using a 1:8 twist 18" Rainier Ultramatch barrel and while most of my reloading in the past has been more for plinking with an Aimpoint, I would like to dial in some rounds to get this as accurate as I can be (the limiting factor will definitely end up being me...)

I have some 55g Hornady VMax and they seemed to do well, I am not too sure as I was shooting prone versus off some sandbags. Anyone else with a similar setup have any bullet suggestions? I want to load up a few different ones next time I go out but I am not sure what else I should try.

Thanks in advance

[Coal Dragger]

You can load anything up to around 80gr, although for magazine length loads a 77gr will be about the heaviest you'll be able to fit in the magazine.

I have a 1:7 Daniel Defense S2W contour barrel and it really really really likes 77gr Sierra Matchkings. Turns in .5" 5 shot groups at 100 yards pretty routinely when I can do my part.

[Firefox]

I also support the 77s for a 1/8 twist barrel. I have an SPR I built with a 1/8 barrel and .223 wylde chamber. From playing around with different bullet weights and options from 55-77 the 77s have both grouped the tightest and most consistent for me. Note that I am talking about shooting at 100yds with factory ammunition, I'd imagine you would be able to get much more consistent with your own loads. My best results were with Blackhills 77gr red box.

[Coal Dragger]

That Black Hills 77gr load is a winner for me too, and is what I tried to duplicate with my reloads. I think I have pretty well succeeded, and for once it wasn't too hard to arrive at a load that did it.

[ChefDementia]

I've tossed everything from 36gr to 80gr rounds through my 1 in 8 barrel with pretty good results.

[TheBelly]

I've had pretty inconsistent accuracy results with BH ammo. This is on their 77 gr match hpbt stuff.

I'll stick to hand loading these days.

[bp7178]

Hard not to go with the 77 gr. Sierra projectile.

My average 5-shot group stretched across 5 groups, 25 rounds total, is right at .75". This is off of a bi-pod and a rear bag, 14.5" Noveske Afghan. Pretty consistent overall, smallest was about .6" biggest was about .8"

These are hand loads and on the upper end of velocity and slightly over the max charge for .223 pressure. I could probably shrink it a bit by slowing it down, but I want this to be a hunting/long range load.

[markm]

My best results were with Blackhills 77gr red box.

It's a real testament to that bullet that even those slappies at Black Hills can't screw it up.

We cranked up our H322 load 4 tenths yesterday and got some promising velocities... Might have a 5.56 load.

[jstone]

If you like the vmax try the 53 instead of the 55. It was a new design a few years ago. The 55 has a bc of .255 and the 53 is .290. The 53s can hange with the 77matchking out to about 500yards when loaded 3000fps+.

[skywalkrNCSU]

Good deal, thanks for the info everyone. Whenever I can find some I think I will try the 53's and the 77's.

Thanks again

[Coal Dragger]

If you like the vmax try the 53 instead of the 55. It was a new design a few years ago. The 55 has a bc of .255 and the 53 is .290. The 53s can hange with the 77matchking out to about 500yards when loaded 3000fps+.

Oooohhhh, I see some of these going down range in a p-dog town near me soon. If I can find any to load that is.

[goodoleboy]

Good deal, thanks for the info everyone. Whenever I can find some I think I will try the 53's and the 77's.

Thanks again

With a 1:8 twist, keeping the bullets magazine length is going to be the only limiting factor you will encounter. I am kind of fond of the 75 gr. Hornady BTHP, but I'm sure the Sierra Match Kings will do just as good.

[Jerseymike]

I've had good luck with 69 smks with varget in an 8 twist barrel. Sub moa at 100