AR15 going from stock m4 barrel to 24" Varment

[helz_mcfugly]

I have a Bushmaster AR15 M4 with a 16" barrel. right out of the box at 100 yards I was shooting 1 1/2 to 2 inch groups. I free floated the factory barrel and improved my groups to 1 to 1 1/2 inchs. Now Im puting a Bushmaster A3 Varmint Upper with a free floated E.R. Shaw 24" SS Bull Barrel with a 1/9 twist on it.
1. Does anyone have one of these barrels?
2. how much tighter should my groups get at 100, 200 yards?
3. what grain bullet and powder charge does this barrel like to eat?

I have been using hornady 55 grain fmjbt with 21 grains of H322.

here is gun before and after the bull barrel

AFTER

 

[rcmodel]

I have been using Hornady 55 grain fmjbt with 21 grains of H322.

If you are after accuracy, you will have to change to accurate bullets.

Nobody's FMJ-BT bullets will do much better then 1 to 1 1/2 MOA out of any barrel.

Try Match HP's, or Hornady V-Max, or Nosler Ballistic-Tips.

Almost any bullet with the jacket opening in the nose will group better then FMJ with the opening in the base.

Because all the bases are square, and all exactly the same.

rcmodel

 

[helz_mcfugly]

should I go to a higher grain for the 200 yard range? like 69 fmjhp?

 

[rcmodel]

If you shoot in the wind, it couldn't hurt.

rcmodel

 

[gvnwst]

Nobody's FMJ-BT bullets will do much better then 1 to 1 1/2 MOA out of any barrel.

tell that to lapua.....

for the most part, yes go with better bullets, try some hornady TAP or their match ammo. Federal gold match sets the standard of match ammo from the factory. you should get around .75 MOA groups at ranges to 300 with the correct ammo.