Drilling/Tapping Forward Scope Rail Srew Hole?

seagiant

Cast Iron

Joined

May 24, 2005

Location

Central Fla. USA

• Aug 21, 2020

• #1

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???

 

Kurt Learning

Cast Iron

Joined

Jul 26, 2018

• Aug 22, 2020

• #2

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.

 

seagiant

Cast Iron

Joined

May 24, 2005

Location

Central Fla. USA

• Aug 22, 2020

• #3

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!

 

W

wesg

Titanium

Joined

Nov 4, 2004

Location

Cedar Park, TX - Boulder Creek/Redwood City, CA

• Aug 22, 2020

• #4

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

 

seagiant

Cast Iron

Joined

May 24, 2005

Location

Central Fla. USA

• Aug 22, 2020

• #5

Hi,
Thanks!

 

P

pat_j0nes

Aluminum

Joined

Sep 9, 2018

Location

Colorado, US of A

• Aug 22, 2020

• #6

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

--
Pat Jones
Firestone CO

 

C

Clemson

Aluminum

Joined

Feb 15, 2006

Location

Upstate SC

• Sep 1, 2020

• #7

pat_j0nes said:

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

--
Pat Jones
Firestone CO

Click to expand...

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

 

K

kendog

Cast Iron

Joined

Apr 10, 2008

Location

West Coast

• Sep 6, 2020

• #8

seagiant said:

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!

Click to expand...

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

 

T

tobnpr

Hot Rolled

Joined

Sep 27, 2015

• Sep 6, 2020

• #9

^^^^
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.