Shot a new gun today, here are the results. These are two seperate loads with very similar vertical stringing.
Gun had previously had a new stock installed and when I received it it looked like there was a clear problem, but I shot it as it because I was told it shot as it was. I am hoping to get some verification that this is a classical bedding issue. There was at least 10 minutes between strings. The shots strung out in a line as I shot.
Those are some great groups for a Browning, she's a keeper!
Looks more like stress in the barrel being released as it heats.
Normally a bedding issue will be randomly all over and not walking.
Shoot 1 bullet every 15 minutes and see if they stay in a circular and smaller pattern.
My A Bolt 270 did some very similar things when I was shooting IMR 4350 but the more I shot it the less it happened and I figured it must have been something to do with my shooting form. One day I tried out RL 22 and the vertical stringing basically disappeared but when my dad would shoot it he seemed to get vertical groups so I honestly wonder if some of the problem was the way the gun is held off the bench.
Keep playing around with it, and try rebedding it cause I don't think it will do anything but help out your situation. I think it'll end up shooting a lot better than it currently is.
first thing on any a-bolt is check to see that the front action screw is not bottoming out on the barrel thread tennon, unlike a remy or savage the a-bolts front screw goes into the front reciever ring under the barrel tennon. contact here is bad.
same goes for the front scope base screw.
If your good in those two spots it is time to experiment a little, two things to try.
1****Cut up a buisness card and stick it under the front reciever ring between the action and the stock. What this will do when tightened up is cause your barrel to point up slightly in the fore-end thus having the effect of more free float.
Shoot the gun this way. look for a NOTICABLE change in group shape and size.
If it changes greatly from your verticle string then yes you could correct the issue with bedding and free float.
2**** stack up buisness cards under the barrel in the tip of the forend to increase the woods upward pressure on the barrel. Look for a noticable difference in your groups. If this causes them to shrink you can make a permanant shim in the fore-end with epoxy.
Really what your looking for is groups that print a round pattern rather than a string, once you get a round pattern then it is time to try and shrink that pattern.
If your gun is in fact walking bullets increasingly up to the top right and each shot goes further high right I would shoot about 15-20 in a row and see what happens when they hit the point that they no longer go high and right. They may get real loose and squirly or stop and start hitting a similar spot. If they continue for any lenght of time I would say barrel stress.
Have you tried multiple loads in the gun and they all do simmilar stringing?
another way to check the barrel stress is to shoot a 5 shot group letting the barrel cool for 20 minutes between each shot. If the same load that strings now stays relativly centered it could be stress in the barrel. I had a friend with a barrel that walked in the same manner as yours is in the above targets. he sent it off to cyrogenically treat and it did help to bring the stringing under control
Well I went back out today and reshot the Browning. With 30 min between shots, I had the EXACT same pattern, but a smaller group. I managed about .75" between the 3 shots at 200 yards, for a total 1.5" .75moa group. The thing is I still feel this is being driven my something specific that is fixable.
In the last two days I have shot about a dozen groups between 200 and 500 yards with four different guns, including another Browning A-bolt synthetic in 7mm and managed multiple all moa or better groups and none had the same pattern except this gun so while I am no comp shooter I don't think this one is me.
The scope is a brand new Vortex mounted with Talley one piece 30mm by a pretty good gunsmith. I will have him check the mounts.
I will take my groups and the gun into the smith and ask him what he thinks. Guessing I will have him yank the stock off and check everything, floating the barrel and bedding as needed.