Author Topic: sight base holes,,,,shallow?! (Read 541 times)

alan in ga · « **on:** July 18, 2003, 05:25:35 PM »

removed the rear sight on my Stainless Steel 22 LR Match 10" T/C barrel to mount a scope base. Only found about 4 threads in holes. I have a bottoming tap [6-48] to clean out the threads. It's been a few years since my last Contender,,but I seem to think I had 6 threads before. How many threads/deep are todays Contender barrels? I know I can shorten my base screws [Weaver base],,but don't I need about 6 threads grasp?
I can always drill and tap deeper,,,but wondered what today's Contender barrels are getting at the factory in the rear sight holes.
Thanks, Alan in GA. :roll:

223Larry · « **Reply #1 on:** July 18, 2003, 06:00:03 PM »

sounds like you might have buildup of factory lock tight.try a under sized drill bit to get down to the metal.

alan in ga · « **Reply #2 on:** July 18, 2003, 06:06:13 PM »

red loctite in middle two holes was picked out. Still only 4, maybe 4 1/2 threads. Gonna drill for two more threads I think.
thanks.

KN · « **Reply #3 on:** July 18, 2003, 06:09:23 PM »

I've never personally experienced this, but I remember a while back this came up with some people complaining about shallow holes. You sure wouldn't think it would be a problem in a 22 barrel with all the extra meat to play with. KN

Bullseye · « **Reply #4 on:** July 18, 2003, 06:20:49 PM »

Just put a base on my 375 Win. Had to grind .030" off all the screws. Had 3-4 threads in the hole. Usually if there is a problem it is just with one hole, this is the first time I have seen all 4 holes off by the same amount.

Big Gun · « **Reply #5 on:** July 19, 2003, 03:08:02 AM »

The normal rule of thumb for any bolt is that it should have a minimum of one bolt diameter of threads inside the hole. In other words if 4 threads is the same lenght as the diameter of the bolt itself then that would be the minimum engagment you should have between the bolt and the bolt hole. On Mike Bellm's web site he talks a bit about this problem.