Problem gun

Yes.

I have tried the Accubond 180's and 175 cc and 190 cc.

I have never had a problem getting their blems to shoot accurately in every other gun.

What do you suggest?

Bergers. We use CCs in high power, our scoring rings are generous, plus shooting sling. 1 MOA gun can clean a 2 minute 10 ring. For utmost precision I would not use them if your goal is half minute most of the times.

Check the bedding integrity. Clamp the barrel in a vise and indicate the stock movement as you loosen/,tighten any of the action screws. Back when I shot hunter benchrest, the acceptable max movement is 0.002. I still demand that whether I did the bedding myself of paid someone to do it.
 
Someone mentioned to me that I should hold the barrel in one hand and strike the underside of the barrel about 6" from the action, three times, nice and hard (within reason). It's like a poor man's stress relieving method. He tried it on two guns. They went from 1.25-1.5" guns to .5" and .33" respectively.

Ima give that a shot too.
Trying to wrap my head around this procedure. What are you striking the barrel with, palm of your hand, rubber mallet. How are you holding the barrel, from the top side with down pressure to prevent the gun from flying in the air? Interesting suggestion for sure.
 
Trying to wrap my head around this procedure. What are you striking the barrel with, palm of your hand, rubber mallet. How are you holding the barrel, from the top side with down pressure to prevent the gun from flying in the air? Interesting suggestion for sure.
My friend used a ball peen hammer. I'll probably go for a mallet of some sort.

Remove the barreled action. Hold the top of the barrel in your hand, hanging freely, and smack away.
 
Someone mentioned to me that I should hold the barrel in one hand and strike the underside of the barrel about 6" from the action, three times, nice and hard (within reason). It's like a poor man's stress relieving method. He tried it on two guns. They went from 1.25-1.5" guns to .5" and .33" respectively.

Ima give that a shot too.
That is the first time I've heard that.
 
I have only had a couple. Guns that refused to group consistently. One, I fixed by re-crowning. This one is causing some head scratching.

300 Win Mag, Winchester CRF mod 70, Shilen barrel, McMillan A3 stock, Leupold VX-6, 3-18x56.

I have tried RL-22 and H4831SC. 190 Nosler Custom Competition (identical to SMK), 180 Nosler Accubond and 175 Custom Competition.

Most groups are 1.2" or so. It will shoot a .5" then a 1"+ with the same load. No load has shot consistently good groups.

I'm shooting 3 shot groups, letting the gun cool between shots and shooting 2 other rifles.

This gun is a new build. Straight from the gunsmith.

Rifle is bedded.

More than adequate clearance between stock and barrel from 3" in front of tang.

Indoor Air conditioned 100 yard range.

I can make mistakes shooting, but this is not me. When I pull a shot, I know it and either don't count it or I can call it close enough to get an accurate measurement.

I'm shooting great little groups with the 7 mag 308 and 6.5 CM between crappy groups with the 300 WM.

I have played with seating depth, taking it all the way out to 3.535". Helps, but no consistency.

Ideas?
Just my 2 cents worth! I tried those bullets and could not get an accurate load in my 300 Allen Extreme custom rifle. Went to Berger, seated 15 thousandth's off the lands and H1000. That solved my problem. Somewhere in that process I discovered the scope bases were loose too!
Got the Accubonds to shoot but not the Hornady bullets!
 
My friend used a ball peen hammer. I'll probably go for a mallet of some sort.

Remove the barreled action. Hold the top of the barrel in your hand, hanging freely, and smack away.
Hmmm, ball peen hammer, whoa. I would be more concerned of having a stress relieved bedding job. Have never heard of the above ever. He must feel that smacking the barrel relieves any stress from the toqueing of the action to the barrel. Interesting thought. I would really check your bedding job. Make sure the bottom metal is not binding. I've had a few rifles where bedding the bottom metal was significant in the overall bedding. If the inlet on the bottom is off and it can put stress into the action when action screws are torqued.
 
When you shoot, do you leave the gun exactly in the rest btwn shots? Or do you shoot the other 2guns while you let it cool. If you move your guns position btwn shots, that often is the difference btwn avg groups and great groups. You have to recreate every part of your positioning as much as possible for each shot.
 
Hmmm, ball peen hammer, whoa. I would be more concerned of having a stress relieved bedding job. Have never heard of the above ever. He must feel that smacking the barrel relieves any stress from the toqueing of the action to the barrel. Interesting thought. I would really check your bedding job. Make sure the bottom metal is not binding. I've had a few rifles where bedding the bottom metal was significant in the overall bedding. If the inlet on the bottom is off and it can put stress into the action when action screws are torqued.
Hmm. You may have something there. I'll have to check that.
 
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