Change recipe and differant point of impact.

[Malapai]

Hi folks'

I've been reloading 223 using a recipe of
H335 26.5 gr up to 28 gr.
Barnes Varmint Grenade bullet 36 gr.
Win brass
WSR primer
OAL of 2.225

Shooting this through a 20" shaw heavy stainless 1-9 twist.

I couldnt get groups better than 4 inches at 200 yds. Called Barnes, tech told me he uses the same bullet through his 1-7, 1-8 bushmaster barrels with 1/2" groups. Advised me to make OAL longer and bump up charge to 28 gr H335.

With OAL at 2.255 and 28gr powder the groups were only slightly better.

Decided to go to slower powder and worked up a few differant loads using Win748. Same OAL with 26gr and 27gr loads.

Go to the range and notice the 26gr loads grouping at 1.5" at 200yds. However the groups are 10 inches directly to the right of the bulleye. This brings up a few questions to pose to you all..

1. did this new powder cause such a differant point of impact change or did something else happen like knocking my scope out of whack, etc.. Differant powder charges of the H335 would only cause variances in elevation not windage and certainly not 10 inches to the right.

2. The Barnes Varmint Grenade bullet is as long as most 55gr bullets. This allows for better stability in the barrel. The slower powder must have put me in a sweet spot with the barrel somehow as the groups with the Win748 are 150% better than with the H335. Can anyone confirm this?

3. Im a little new at this can anyone see anything else that i am doing wrong or that I need to try?

This recipe with the Win748 is promising and I am not dissapoined with 1.5" groups at 200 yds. I am shooting an AR-15 that I built up with a Model 1 upper and a DPMS lower and factory crap trigger. I will install a drop-in Chip McCormick that will hopefully further my groups. The scope is a cheapy 4-16 with mil-dot recticle.



Thanks

 

[Walkalong]

Differant powder charges of the H335 would only cause variances in elevation not windage and certainly not 10 inches to the right

That's right. I find it very hard to believe the powder did that.

The scope is a cheapy 4-16 with mil-dot recticle

Hmmmm....... Try a different scope. Did you bump it accidentally in between?

I would suspect the scope, or loose mounts.

 

[RecoilRob]

The 26grn load of 748 is going quite a bit slower than your 26.5 of 335 and a LOT slower than your 28grn version. My books suggest that the hotter 335 load is going over 3400fps which might be too fast for the bullet in that barrel.

Before I went too much farther, I'd try a H335 load around 24grns or so which should come close to the 26-748 version and see if the groups don't tighten up. If they do, you have found that the problem is the bullet/barrel interface just doesn't like spitting them out so fast.

The moving of the group 10" right @ 200yds is a bit surprising, but surprises are not uncommon in this business of shooting! I'm assuming the 27grn 748 load was at POA? If so, you have discovered an accuracy node at that velocity with that powder. Weird, huh?

If both 748 loads are over to the right, I'm with Walkalong and suspecting the scope/mounts have moved.

 

[rcmodel]

Only sure way to find out is go back and shoot some of the original loads you had it zeroed with.

If it is still shooting where it was, it's not the scope, it's the load change.


rcmodel

 

[taliv]

i also would suspect the scope. i've had minute powder changes move groups around 2-3" at 200yrd, but never 10". that's pretty wild.