optic won't tighten

Well, I got my Primary Arms Micro Dot optic in today and was all excited until I put it on the rail and realized it won't tighten down enough to prevent its sliding back and forth. Primary arms said they could send me a new base they can grind down but i'd need a "caliber" to get the measurement of my rail.. hmmmm.. no clue? Any help or should I just take it to a local gunsmith to mount it?

Sometimes called dial or digital calipers................

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kowen1971 wrote:Well, I got my Primary Arms Micro Dot optic in today and was all excited until I put it on the rail and realized it won't tighten down enough to prevent its sliding back and forth. Primary arms said they could send me a new base they can grind down but i'd need a "caliber" to get the measurement of my rail.. hmmmm.. no clue? Any help or should I just take it to a local gunsmith to mount it?

Whoever made you rail should have that information.

You may have a Weaver/Picatiny issue. Learn more here

http://www.brownells.com/.aspx/lid=12631/GunTechdetail/Picatinny_Rails__Weaver_Rails__What_s_The_Difference_

We actually have a harbor freight close by. I'll check it out. And the rail is on the Tapco intrafuse quad system.