To some people this is a huge no-no, but sometimes it is simply necessary.

My very first scoped rifle (at 12 years old) was a brand new Marlin Model 57 on which the mounting holes had been drilled crooked at the factory -- or maybe the barrel was off-face and didn't point the same way the receiver did. After all, it's been over 50 years and everything you "remember" from a half-century ago might not be exactly like you thought.

Anyway, being a farm boy and thinking the way farm boys think, my instinct was not to complain to the store or the factory, but simply to fix it so it would work. I took two pairs of pliers and bent a penny back and forth until it broke in two. Placing the square edge down between the rear of the mount and the fixed side of the ring clamp squared the scope with the barrel nicely. I won a turkey at the local Firemen's turkey shoot fundraiser with that Marlin a few months later.

A year or so later I got my first centerfire, a Sako with Redfield rings and bases. Apparently, the front Redfield base was too thin, causing the scope to point lower than the barrel. Using all of the adjustment available in the Leupold still put the bullets higher than the target. It didn't take a lot of gray matter to figure out that if I put a few strips of aluminum foil between the bottom of the front ring and the scope tube that the scope tube would have to tilt upward a bit, thus bringing the POI down. Fifty-plus years later I still have that Sako with the same Leupold and the same aluminum shims under the scope tube. And it still shoots right where its aimed.

Just a few months ago I had a friend ask me if I could get a .17 Rem, a custom job that he had bought used, to zero. I guess there was a pretty mean curve in that barrel, because while it would boresight okay, the impact was way high and right -- far enough to be beyond the scope adjustments. Breaking out the shims, I got its nominal POI close to the centered adjustments of the scope and found that, by golly, once you found the paper that little dude would shoot -- five shots in a half-inch or less all day long. When I returned it to the owner he was disappointed at my report (and oblivious to the gun's outstanding performance), and said he would take it to the next gun show and sell it. That was despite the fact that he couldn't even see the shims I'd used.

Moral of story: I'm disappointed if a gun or its mounting system doesn't put the scope pretty close to center. But it's not the end of the world and just a tiny bit of judicious tinkering can put things right.

Shims will work, Burris Signature rings with posi-loc inserts work even better IMO. Nice work getting it done.

When mounting the old reticle-movement scopes I favour, shims are often needed to keep the post or crosswire centred, though some rifles with dovetails seem so well made nothing is needed.

I like thin bits of stainless sheet but pieces of an old feeler gauge are good, too. I suspect good gunsmiths may stone the bottom of bases etc to avoid shims but IIRC Townsend Whelen used to put a long steel rod in the rings and give them a wrench - not something I would risk.

quote:

Originally posted by JGRaider:
Shims will work, Burris Signature rings with posi-loc inserts work even better IMO. Nice work getting it done.

Yes, but those weren't around a half-century ago, and if they had been they would have been beyond the financial capacity of a farm boy's very nominal wages.

Cut up aluminum beer cans work as shim material also.

quote:

Originally posted by df06:
Cut up aluminum beer cans work as shim material also.

I have a tool box with all sorts of screw drivers in it - I have cut Coke cans into small pieces and have them ready in that box just for this.

quote:

Originally posted by df06:
Cut up aluminum beer cans work as shim material also.

I have use these on a couple of rifle.

I have three different rifles that had to be shimmed, one of them for rimfire benchrest. I shim the bases, not the rings. I wonder about the wisdom, then just go and shoot.

Shims when you need them is the only suitable answer I know of, short of surface grinding your action and hand fitting your bases, which is a pretty good idea,

When everything is square to the world, all these other problems are non existent.