Thread: Drilling/Tapping Forward Scope Rail Srew Hole?

Hi,
I found an older Savage LH 110 Long Action in 22-250.

It has the older size 6 screw holes for the rail and I want to upgrade to 8-40.

All the holes are clear of course except the most forward one where the barrel is screwed in.

Was wondering if I could just drill the forward hole to the barrel threads, and bottom tap it with out pulling the barrel???

It is a little trickier to do it that way, but you can do it. If I remember correctly, the trick is to us a jig or fixture so that you get perfect alignment, And depending on the depth of the hole use a taper or plug tap and finish with a bottoming tap.

Hi,
Thanks, I have a Bridgeport so will see if I can get it in the vise and go from there.

Bottoming tap has been ordered, also looking at using a mill cutter instead of drill bit for that hole to get as far down as possible (just on top of barrel threads) with the new hole!

Not gonna hurt to go to the bottom of the threads if you feel like it.

Hi,
Thanks!

If you have headspace gauges and a wrench, it really is easier to pull the barrel.

--
Pat Jones
Firestone CO

Originally Posted by pat_j0nes

If you have headspace gauges and a wrench, it really is easier to pull the barrel.

--
Pat Jones
Firestone CO

I totally agree with Pat. I would say, however, that with a 22-250 you are not gaining anything with your changing from 6-48 to 8-40 screws.

Bill Jacobs

Originally Posted by seagiant

Hi,
Thanks, I have a Bridgeport so will see if I can get it in the vise and go from there.

Bottoming tap has been ordered, also looking at using a mill cutter instead of drill bit for that hole to get as far down as possible (just on top of barrel threads) with the new hole!

9/64ths end mill (center cutting) will cut a good hole for an 8-40 tap.

^^^^
Yep.

Good tutorial, pretty straightforward- much more so with a DRO.
Screw spacing is listed in the article, also on M700 receiver shop prints online.