I have a Bushmaster 223cal with 16" barrel 1:9 twist.
I would like to know what is the heaviest bullet that my barrel will stabilixe properly? I normaally use 55gr FMJ, but I would like to try 69gr Federal Matchkings and even 75gr Hornadys.

What do you guys think??

BTW, with advice from this board, I was able to change my upper assembly from carry handle to flat-top. It was so easy to do...thanks!!

1 in 9 twist .223's are supposed to stabilize 55 to 69 grain bullets

Leopardtrack, what do you want to do with those heavy match bullets in a 16" 1/9 twist barrel?

I think you might be better served by something like the Federal P223Q load (60gr. Nosler partition) with your setup.

I've got two ARs with 16" and 1/9" twist bbls. and the Nosler 60 partition is my favorite "do everything" bullet in these guns.

Compare them side-by-side against some heavier match ammo (like the Fed. GM223M) and see what you think.

73 grain BT, Barnes X may be too long.

Thanks fellas! I really just use the AR for screwing around shooting stuff in the woods, etc and some hunting such as coyote, woodchuck, and an occasional deer.
I "aquired" a case of the 69gr Federal MatchKings so I was wondering if the were too long for my 1/9 twist....I didn't shoot them yet. Seems like a good load for all of the above scenarios, along with our up-coming internal war which will be triggered by nature or a man made catastrophy. It will be a mess, and when you call the police....they aren't coming. Survival of the fittest.
Hey everyone, Leoprdtrack wishes you all a happy new year!!!

Depends on the bullet. Stabilization deals with length not weight. You can use any OTM up to 75gr but you can not use tipped 75gr bullets, Amax/Scirocco. You can use 62gr TSX but not 70gr TSX. 77gr OTM will appear to stabilize at 100 yards but are wobbling/yawing pretty good at 200 yards.
The Federal 69gr will stabilize just fine.

Perry

My 14.5" Bushy with permanent FH in 1:9 handles 69 gr match bullets well. Also likes 60 gr Noslers and 55 gr NBTs.

I'd not bother with anything heavier than the 69 gr bullet.

Good luck!

I've found up to 69gr (no tip) usually work just fine in almost all 1/9 and many 1/9 can handle 72gr but not all. Only realy way to know for sure is tryin it out.

I use 50..65gr. Have never tried lighter or heavier.

velocity is as imprtant as twist rate- so, a 1 16 incher may not stabilze 75s, but a 20 incher may-due to the exit velocity whgich determines rotational rate.

Example, my 16 inch 1:9 CAR does not handle 75 Amaxs (8inch wobbly groups at 100), but one with a 20 inch barrel does just fine (8 inch groups at 600)....

Velocity from the 16 incher is only 2375, the 20 inch gets 2740. Same loads, same barrel make, same reamer.

Don't know where the frown thingy came from, should be a :9

quote:

Originally posted by Leopardtrack:
Thanks fellas! I really just use the AR for screwing around shooting stuff in the woods, etc and some hunting such as coyote, woodchuck, and an occasional deer.
I "aquired" a case of the 69gr Federal MatchKings so I was wondering if the were too long for my 1/9 twist....I didn't shoot them yet. Seems like a good load for all of the above scenarios, along with our up-coming internal war which will be triggered by nature or a man made catastrophy. It will be a mess, and when you call the police....they aren't coming. Survival of the fittest.
Hey everyone, Leoprdtrack wishes you all a happy new year!!!

The 9" twist should handle the 69 match loads just fine as far as accuracy goes. However you probably will be disappointed on terminal effectiveness as compared to varmint bullets in when shooting wood chucks and coyotes. With the shorter 16" barrel you will not be able to drive heavier bullets fast enough for any accuracy.

I would suggestyou shoot the match ammo for practice on the range and either load or buy ammo with good varmint ballist tip bullets of 55 gr. You will then have the velocity and terminal effect for an effective range of 200 - 250 yards, maybe 300 yards if you have a pefect heart lung shot, on wood chucks and coyotes. I've found the 64 gr Winchester PP to be an excellent deer bullet out of 9" twist ARs. You should be able to get 2800 fps with AA2460 powder out of your 16" barrel. It will be effective to 200 yards on deer if you put the bullet in the right place.

Larry Gibson

Ive shot 75 grain Hornady bthp's, both reloads and red box for many years in my 1-9 inch out to 900 yards.

they kill rock chucks well out to 200 yds.

andy

You should be ok up to the 90 gr.I have shot the 90gr a-max and the 80gr bergers and the rifle I have likes them.

The Greenhill formula figures you should be able to stablize .224" bullets to 1.0" maximum length with a 1:9 twist. Assumes bullet is light enough to fire with a muzzle velocity at or above 2,800 fps.

Greenhill Twist Calculator.

I don't think there's anything to be gained by using heavy match bullets (over 69 gr.) in a 16" 1/9" twist barrel!

quote:

Originally posted by DaMan:
I don't think there's anything to be gained by using heavy match bullets (over 69 gr.) in a 16" 1/9" twist barrel!

I've shot the 69gr and 77gr SMK out of my 16" Bushmaster rifle. They worked fine out to 200 yards, I haven't shot further with that rifle. The military has stuck with Sierra because of international convention and the SMK counts as a "non-expanding match" bullet. I really like the Sierra 65gr BTSP, for my purposes it's as accurate as the SMK, hits hard (for a .223) and expands nicely.

YMMV