I lurk here all the time, and am just getting started in longer (itís all relative) range shooting. I recently was able to go through my factory deer rifle and perform some of the basic accurizing work. I have a Remington 700 BDL, in 30-06 with a Leupold 3x9. Pre-accurizing the rifle would only hold a ~4Ē group at 100 yds. I bedded the action with devcon (no pillars), lightened and adjusted the factory trigger (2 lbs), made sure the barrel was floated, and lapped the locking lugs to ~90% contact. I took it out to see how I did with all my improvements, and it did help pretty significantly. After a getting warmed up, and trying really hard to be conscious of my hold, cheek weld, breathing etc. I was able to get it down to a 3/4Ē wide by 2Ē tall 6-shot grouping at 100yds. This was off of fairly stable bench, with sand bag under the front, and my fist under the rear.
Question time Ė Any ideas for what could be causing the vertical stringing? The shots did not ďwalkĒ up, they were high, low, low, high etc. This leads me to believe it is probably not heat warping, and I tried to wait a few minutes between shots to allow the barrel to cool. I am thinking that my hold may be the issue, Iíve read a lot about a hard front rest potentially causing vertical issues, but my shooting wasnít nearly as accurate when I hand my left hand on the forearm (trying to rein in the kick-up), it was better, when I had it as a fist under the stock. Also, lots of people shoot off of bipods, with their fist under the rear, so donít understand how that could be causing it.
All this shooting was done with 165 gr Remington core-lokts. I know that this isnít exactly match grade ammo, but itís what I have on-hand. I will eventually try some nicer ammo, but I canít afford to get into handloading right now.
Any help or tips would be appreciated. I'd love to figure out this issue, and end up with a sub-moa rifle!
I would recommend shooting off of a solid rear bag as a first step. Something filled tight with sand and some ears will do the trick. Set up so that the rifle will hold a natural point of aim without you manipulating it. Keep working on your mechanics the way you discussed above, and I would guess you will see some if that stringing disappear.
If not, the only cure is all-in precision reloading!!
I'm not sure how these bags are supposed to work. I was using the type meant for shooting (with the ears), but it seems that inevitably, they are always too low, or won't put the natural point of aim in the right spot. I understand the point of your comment though. Try a solid rear rest instead of the fist. Maybe next time I'll bring a phone book or something to shim it up to the right spot.
Not the best picture, but this is what I shoot off of for sight in or yard varmints on rifles that don't have a bipod. It is basically a cheap fold out front tripod and a rear bag from Protektor. Even on my LR rigs with bipods, I am typically able to get a sight picture by moving the rear bag a little farther back on the stock.
Sounds like you have a really tall front bag or a really short rear bag (or both).
This is similar to what I have. I don't think the front bag is tall enough. Regardless, I think i get the point. I'll try to figure out something more solid to shoot from, and see if that helps. Any other ideas of what it could be? Just trying to work all the gremlins out.