Strange horizontal stringing

[carrollshooter]

I have a 700 action with a Broughton light varmit contour barrel in 22 PPC installed by highly reputable gunsmith. The action was trued by the same gunsmith. It was bedded by the same gunsmith. An oversize recoil lug was pinned to the action. It has never shot consistently below .5 MOA under the best of conditions. It usually hovered around .75 MOA. The gunsmith took it back and rebedded it but he could not get groups to get any smaller in his tests. He gave up on it. I put the action in a Remington Police sniper stock with the built in aluminum bedding block. I think the stock is a Macmillian. I skim bedded it with Devcon aluminum putty on the bottom third of the circumference of the action and barrel except for the action along the sides of the rails where it is free floated. The barrel is bedded for about 3/4" in front of the recoil lug. I have verified that the barrel is free floating with a minimum of 1/16" clearance in front of the bedding. The problem I am having now is extreme horizontal stringing. Five shot groups rarely go more than .375 MOA vertically but are 1-1.25 MOA horizontally. This is very consistent. I have tried three popular powders in my loads and all three shoot about the same. When I bedded the rifle I relieved only the bottom of the recoil lug. Yesterday I relieved the sides and front of the recoil lug but this did not change the grouping at all. I have many groups that will have three or four shots in .25 MOA but one or two shots will string horizontally to open up the group to 1 MOA or larger. Any ideas on what to try next?

 

[noload]

Are you shooting with a bipod or rest? My guess, it is you, and something in your body contact and or rear bag set up. Bipod can sometimes hang up on one pod on the recoil, and sending your group sideways. This happened to me with a wide bipod, ...1/2" hi group at 300 yds, with 3.5" wide (15 shots). My thoughts are your gun groups too good sometimes to be a bad load or bedding job. A bad load or a bad bedding job, would be bad all the time....and not give a .25 moa anytime.

 

[wapiti25]

I would suspect the barrel fit or action. I would Check the barrel threads in the action and on the barrel also the face of the action to the threads. "Truing an action" means different things to different people. Have the threads been re-cut true to the bolt raceway? I would suspect your shooting set-up but the smith also could not make it work. Last resort would be to cut off the threads and re-chamber.

 

[carrollshooter]

Thanks for the input. I am shooting off of a heavy tripod rest and bunny bag rear. The conditions that I tested in were dead calm wind. My range is in a creek bottom about 100 feet wide that is protected by woods on three sides. I look at the leaves all around to judge wind. I shoot five shot groups and let the barrel cool between groups. If the barrel is uncomfortable to the touch, it is too hot for my testing. I did not say that I had gotten any good groups. My statement was that the vertical spread usually did not go over .25 MOA. I have several other rifles that I shoot on this setup, some are lighter in weight but I do not have the horizontal spread with the others. The previous barrel was a Douglas air gage in the same caliber and it shot well. The gunsmith that installed this barrel actually installed two barrels because he could not get the first one to shoot either. This is the only tight necked chambered gun I own but my Cooper 21 in 204 Ruger and my two Savage 12 VLP DBMs in .243 and .308 with factory barrels will out shoot this gun.

 

[gunsandgunsmithing]

I mean this in the best possible way, but...if you're not using wind flags, you can't possibly tell what the wind is doing. Anything is better than nothing at all. Good wind flags are worth their weight in gold but even surveyor tape will usually tell you when NOT to pull the trigger. Often, tha so called
"no wind" condition is the worst, and I've shot quite a bit on a range like you describe...narrow paths thru tree lines are horrible about giving a false sense of security from the wind. What they actually do is make it almost impossible to shoot well, even with flags sometimes.--Mike