5.56 Long-Range Rounds

[GhostDog_usa]

Hi fellas,

This is my first post here....Thanks for letting me in the door

I have a Rock River 5.56 AR15 that I have setup for a (relatively) long-range shooter (see pic HERE ). I currently have the 1-9 twist 16" RR barrel still on the rifle (it's a long wait for a new barrel ). Since I only have the 1-9 twist, I have topped-out at the 69 grain Sierra Match Kings as my projectile of choice, and I have the rifle performing pretty close to 1 MOA. I'm very happy with the rifle out to about 600 yds, but I would like to get to 800 or so without losing the accuracy.

My question is, have any of you had any experience with larger projectiles (75 or 80 grains) in a 1-9 barrel? I know the books say the bullet is not adequately stabilized in the chubbier bullets unless you have a 1-7 or a 1-8 barrel, but I'm curious if anyone has any real-world experiences on the subject that they can share. I guess I'm just one of those guys that doesn't always trust the books to be the final word on the subject

Thanks in advance for any and all thoughts that you may share!

G-Dog

 

[Sig685]

Re: 5.56 Long-Range Rounds

1:9 with 16 inch barrel? I seriously doubt it will stabilize an 80grainer. Buy a box of 100 and try it out. Let us know.

 

[Casey Simpson]

Re: 5.56 Long-Range Rounds

Ghostdog, get some and try it; you might surprise us. All guns are different.
Get The Competitive AR15, by Glenn Zediker. He's the wizard on AR's and their ammo.

 

[Pusher591]

Re: 5.56 Long-Range Rounds

Good luck on the 75's let alone the 80's. I have had luck before with the Hornady T2 75's in a 1-9 twist RRA but its becasue the T2 load is a 5.56 load and not .223. No diffrence in round just the T2 is a couple hundred fps faster thats why I think the 1-9 twist stabalizes it. Forget about going hihger. I tried shooting some 77 smk's thorugh a 1-9 but they key holed a little bit and the accuracy sucked caused I assume they just were not stabalized enough. I tried the 77 smk's through a bushamster,RRA, and a DS arms ar's. All 1-9 twist. None worked.

 

[MitchAlsup]

Re: 5.56 Long-Range Rounds

At altitude (1000 ft+) and in the hotter temperatures, you can probably get away with 75 gr, and you will increase your odds of getting away with it if you push them hard.

 

[michaeltx]

Re: 5.56 Long-Range Rounds

I don't think there's much chance for the 80, they have to be driven pretty hard to stablize in a 1-8 twist.

 

[REELDOC]

Re: 5.56 Long-Range Rounds

Don't give up until you try Hornady 75 grain BTHP's.

 

[GhostDog_usa]

Re: 5.56 Long-Range Rounds

Thanks for all the input guys. I think I'll load up some 75s & see what happens. I shall report back with my findings

 

[Greg Langelius *]

Re: 5.56 Long-Range Rounds

I know the HDY 75gr BTHP Match works in a 1:9" 24" barrel. I also wonder how the 77SMK works, as I think it's made deliberately shorter to work in magazine length cartridges, and may stabilize better because of its shorter length.

 

[1shot2kill]

Re: 5.56 Long-Range Rounds

the 75 gr hornady in theory might work for you but beware they are looong and will have to be a single shot setup same thing goes for most 80 grain projectiles i shoot the 77gr smk and they will fit in your mag with no problem if you want to test the waters nosler makes some good bullets and the military did use the nosler 77gr for a while until sierra put a cannelure on thier 77 gr but the nice thing is they are priced right usually about 45-50.00 for 250 and they make a 69,77 and 80 try them all out and see what it does

 

[308sako]

Re: 5.56 Long-Range Rounds

.

 

[sobrbiker883]

Re: 5.56 Long-Range Rounds

Hornady 75grBTHP match ran fine in my Wilson 1:9 twist.

 

[Jedi]

Re: 5.56 Long-Range Rounds

my general do all load is 60gr BT


replaced my old load runing 69gr smk etc

1k load 75amax, single load only coz of OAL