What Grain Ammo for .223

jbw1776

I have a Bushmaster AR-15 with a 24" extra heavy "match" barrel. The barrel has a 1:8.5 twist rate. My question is this, what grain bullet do you feel is best suited for this barrel/twist? I know different guns like different ammo, but I'm just looking for a starting point. I'm limited to factory ammo and not really looking for the "best" ammo, just the grain. 300-500yd. target shooting is what I've been using it for. I've read what other twist rates generally like, but I'm having a hard time finding a general range for this odd twist. Any help is appreciated. Thanks

Ben

bpost

That is a fast twist for caliber barrel.

Heavier bullets will tend to shoot better. Try several types of ammo to see what your rifle likes.

dcloco

69 Sierra HPBT (excellent bullet by the way, measures at near match quality dimensionally).

Or...there is 70 grain from various manufacturers.

jbw1776

I appreciate the help guys. Is there a bullet I should stay away from, too heavy/light. I've been shooting the 55 grainers in it, and while the accuracy is good, I believe it could be much better. I will give the 69gr. bullets a try.

Ben

nononsense

jbw1776,

You shouldn't have any trouble using lighter weight bullets with your twist rate, I do it all the time with fast twist barrels. You will find that you can use bullets that are up to approximately 0.885" long and still be stable. This should also include the 68 gr. bullets.

This link is for the Federal Ammunition website that has the loaded ammunition for the 69 gr. MatchKing bullets. You can select the column marked "ballistics" and get the charts for each cartridge:

http://www.federalcartridge.com/ballistics/Ammo_Search.aspx?act=choose&firearm=1&s1=1

This is the link for Black Hills Ammunition:

http://www.black-hills.com/rfactorynew.htm

Best.

Gunslinger2005

I have a Bushmaster Varmint Special with the 24" heavy barrel with 1:9" twist. It shoots all the bullets in the 50 to 55 grn weight range that I've tried reasonably well. I haven't tried anything lighter. The 1:9" twist seems to handle anything in the 68 to 70 grn range very well. I haven't tried anything heavier, but from the reports I've heard, some rifles with 1:9" will shoot 70+ grn bullets, while others won't. 1:8.5" isn't much different than 1:9", so you'll just have to try various loads to see what your rifle can handle. The limiting factor may be the cartridge OAL for what will feed through your mags.

gunphreak

I have a 1-9 rifled 16" barrel that I've shot 77gr. ammo through, and it shoots fine. Stick an ss-109 in it (either 55 or 62gr., can't remember), and it keyholes 100yds. downrange. The weight is not really the biggest deciding factor of bullet flight, it is the length of the bullet surface that contacts the barrel that is the real decider.

jimbowby

--Yo jbw--It really doesn't matter, the rifle-or twist-heart beat, breath and squeeze- means ALL.An unstabilized weight bullet can mean 1/2" diff in group---But with proper approch it can still be OK--[xx(][xx(]--JIMBO

jimbowby

-I'm sorry-just to add --my Rem 700bdl Bull shoots 52 gr Sierras at .209"/gr 100 yds with 1-10 twist--remember-heart beat/breath squeeze--good luck--[:p][xx(]--JIMBO

jbw1776

Maybe I'm expecting too much from this rifle/set-up (the one in my sig line). It shoots -1" at 100yds and putting 2" groups at 300yds is normal, all using Federal American Eagle 55gr. I guess I'm just after that elusive "one hole group", but who isn't?[:p] I still think this set up can do better and believe I'll try out the Federal Premium Gold 69gr. with the Sierra Match King bullets. Looking at the two bullets (Match Kings and AE) the Match Kings are considerably longer than the AE's, maybe this barrel will like them a little better. At this point, shooting from a bench, I don't believe I can improve upon anything to get the groups any tighter without trying different ammo. Thanks for all the help and suggestions.

Ben

tsavo303

that's pretty good for 55gr fmj! try a accuracy designed bullet, and I bet you can do better.