Loose scope base--what am I doing wrong?

[Scotticus]

I just got a used 10" .22 lr Contender barrel.  I thought I was going to shoot open sights, but found a cheap red dot  (BSA RD30 for about $25) so I thought what the heck, I'll give it a try.  I bought a Weaver 92A top mount base labeled: "T/C Contender Handgun, Carbine.  It came with the 4 screws to attach it to the barrel.  I just can't seem to get it seated tightly enough.  The screws are tightened as far as I dare (I used a well-fitting blade on my B-Square set), but the base still audibly/visibly  wiggles.  It did not shoot loose--it was like this from the beginning.  I attached the scope anyway and it shoots great but I would still like to get the base snugged down.  What am I doing wrong?  Thanks for your help.

[df06]

Sounds like the screws are bottoming out in the holes before the base is tight.

I'd try shortening the screws a thread at a time till it snugs up.

I use blue loctite in cases like this as well, for scope bases.

Good luck.

[mbk]

df06 is correct, the screws are probably bottoming out.  I have had several barrels over the years that the holes have not been deep enough for the Weaver screw length.  If you have access to the correct size tap, drill and tap a thin piece of strap iron then thread the Weaver screws through it.  File them off a little at a time from the back side, then when you back them out of the threaded hole in the flat iron, it will straighten out any threads that may have rolled over.  It will keep you from cross threading the barrel holes. 

Also you might want to check where you got the barrel used, that the previous owner did not over do with locktite and fill up the bottoms of the holes.  I use a sharp drill bit just smaller than the threaded hole and spin it by hand between thumb and forefinger so as not not damage the barrel threads.

Mike

[Scotticus]

Thanks, guys.

[Bullseye]

The screws could be too long and need shortened a bit.  Generally the problem I have had is from locktite or crud in the hole even with factory new barrels (T/C uses loctite on the sights).

Just make sure the hole is cleaned out using something like a nail or compass point before your shorten the screws.

[hunterspistol]

     Bullseye isn't wrong, those fine threads are hard to clean.  I use a miniature screwdriver set that's hollowground, one of the smaller ones will reach inside the hole to scrape the bottom.  A Q-tip with 1/2 of the cotton ripped off will fill the little hole, add solvent and voila, a thread cleaner.  If bore solvent doesn't take it out, use rubbing alcohol to dry it up and take a look under a really bright light. Some sight screws are shorter than others and I have ran into mounting holes not being deep enough before. Sometimes it takes 3 or 4 tries to get them cleaned up, lots of my tore up Q-tips. Patience wins mostly. I had to dig in my jar of sight parts the other day to find screws that didn't bottom out so, you're not the only one.

[sr sawyer]

A small soldering iron is handy for heating the holes to remove the excess loctite and it will not overheat the barrel like a torch might.  It also works well, because of the pinpoint ability, to heat screws that have been over tightened or locked with no telling what thread locker or epoxy.