4 replies to this topic

[Sodak Jim]

Have any of you had a problem getting enough elevation out of your scope ? Like running out of scope adjustment, and it still shoots too low? Many scope mounts can be shimmed to get you that extra elevation for long range shooting, or just enough to get you more in the middle of your scopes adjustment range.

For instance, I recently had a scope that only had 10 MOA elevation left when the rifle was zeroed for 100 yards. That meant that I could not use a bullet drop turret knob to adjust for targets past 300 yards. The click values for some scopes at the extreme limits of their range are not always very linear or accurate. At this point you really have two choices. You can get a new set of inclinded 20 MOA bases or base at a cost of $80 to $150, or spend about $8 for some shims and a pair of longer base screws. If you can make your own shims, it would be even less money. Always use the torx screws if you can get them. You may have to trim your screws to length but that way you can make them just long enough to not interfere with the bolt. I like to get get everything adjusted and bore-sighted then go back and loctite and torque all the screws.

It works out very close to .001 shim thickness for each MOA gained. (.020 shim gets you 20 MOA). I think that is figured for rings 3.50 inches apart. You can shim the forward mount, or front end of a 1 piece base to get less elevation, if needed.

[Mongojoe]

That's an interesting bit of information... I have never had this problem, but will keep this in mind. I didn't know that you could buy shims for scope bases... I have had to buy extended rings a couple of times however.......... I had a friend that told me once that he put "rubber shims" under the scope itself, in the rings, to raise it. But I don't know if the shims were bought or home-made.

[tuck2]

Burris makes scope with inserts that allows some agjustment. If shims are used on two peice mounts does one have to lapp the rings? Shims should work on a one piece base.

[Sodak Jim]

tuck2, on Jan 1 2008, 11:31 AM, said:

Burris makes scope with inserts that allows some agjustment. If shims are used on two peice mounts does one have to lapp the rings? Shims should work on a one piece base.

It's always a good Idea to lapp, with or without a shim. Even with one piece bases the rings are not always perfect. The more ring to tube contact the better.

[model99er]

Saw a "guest" viewing this, so I thought I'd add my $.02 ... the only scope/mount I ever had to "shim", I used 1 thickness of a plastic shotgun shell. If I recall correcly, that ended up giving me around 2 moa (~6 inches) of "elevation" change.



99er