I'll suggest trying AA2230. I think it was specifically developed for gas guns and bullets in the range of what the military uses. That was the powder that gave me best groups with the 65 gr Sierra, and I think (without going to look) that's what I used for best results with the Partition. I went to H335 purely because I could find plenty of H335 and was having trouble finding more AA2230.

603, did you ever fool with AA2460 with these heavier bullets?

Preciate all the data sharing, everyone!

Gas guns are my nemesis, and I have witnesses.

Only problem is that based on all of the suggestions you now have 17 different powders to test.

Truth be told you can get most any powder to work reasonably in an AR-15 if you have a basket full of patience. Just hang in there with the stuff like H335, Benchmark, and Varget that have proven themselves over the years to be good gas gun choices. If those can't get the job done toss the barrel and get another one.

Does anyone who routinely uses partitions with good accuracy seat close to the lands?

Keeping an eye on this one.

RiverRider, the AA2230 is the only AA powder I've tried.

No joke! JG can ruin an AR by just touching it! Don't ask me how I know this!

If your hunting hogs they must be pretty small in your area if those groups won't get one for you!

I've shot enough of my hand loads to know those are unacceptable. I realize this AR will never lay down a group like my bolt actions, but those will not do. When it's shooting 3" at 100 yards, it is larger than 6" at 200 yards, and becomes over a foot at 300 yards = unacceptable.

KEEP IT FOR 2 LEGGED GAME

I couldn't tell how big the X's were, thought you were getting 1 1/2 inch groups. Most of my hog shooting happens under 75 yards so that would be acceptable.

Re-shot 23.2 gr, and it was all over the show.

Went 25.2-26.0 gr, and nothing impressed me. I remember Chad telling me throw out the first shot, and the shot that the bolt locks open. This is the best there was today. Not sure which shot number was the one low and right. I'm about ready to scratch the bullets and see if the rifle likes 55 gr bullets better.

You might want to try the Nosler 64 gr Bonded Solid Base. It shot better for me than the Partition did, but the groups only got small as I approached max (H335).

Whats Chad always saying...

Its not my rifle doesn't like this bullet, its it doesn't like your powder charge.

Mine loves benchmark, never tried anything else.

I agree with that.

It's in my head, though. The rifle has done pretty well with 55 gr mass produced ammo in the past. Several months ago I got some American Eagle 62 gr FMJ, green tip 5.55. It doesn't shoot them well either. I'm thinking this 1:9" doesn't like bullets heavier (longer) than 55 gr.

Thought faster twist was for longer/heavier bullets?

What is the jump on those 55 grainers? I still think you should try seating them a little deeper.

After I finished up my reloading today, I noticed a target on the cork board in the workshop. It was 5 bullets in an elongated hole. It was a target from a while back when I was using AA2230 under the 65 gr GK. My groups with H335 under that bullet are not as good. Little late to have those thoughts, but after I shoot up the new batch of reloads, I'll go back to the AA2230. It's da powdah.

Faster twist is for longer heavier bullets. Most ARs have a 1:7 or 1:8, mine is 1:9.

No data on a 55 gr jump. Remember, I didn't load the rounds of 55 gr I had previously shot. I might try sticking with 25.8 gr, and play with the jump.

I can't remember a rifle that has given me more trouble to get to shoot. Stupid ARs!

What brand of barrel and is it chrome lined? Considered a new barrel? I know a guy...

The few American Eagles I ever shot were all over the place. I wouldn't use that as a basis...
I have had zero accuracy issues out of my 22" and 16" 1:9 twist rifles up to 69gr SMK. I don't think it's your twist. As bad as this stinks for you, I really think a powder swap would change your results. Good luck!

Thanks for the input.

Yep. You gotta try some Benchmark with those Partitions before you give up on them.

Is Benchmark temp stable?

Supposed to be very.