RT8 has submitted his technique for repairing stripped threads on the top of the reciever.
How-to fix a stripped 10/X receiver:
Must have a drill of some kind. I used a small hand-held electric drill.
1. 8-40 Taper Tap (#395-840-001)=$1.82
2. 28gauge wire jobber-length drill bit (#891-128-140)=$2.45
3. *Pack of 8-40x1/4" torx screws (#080-924-484)=$5.22. That’s enough screws for at least 2, maybe receivers.
4. 1/4" drill bit (#891-201-400)=$3.23 (if you already have one that's close to this size you can use it...its for countersinking the screw heads into your base).
5. T-handle for taps (I used a pair of vicegrips instead) (#395-311-001)=$3.67
6. 16ga jobber length drill bit for opening the receiver holes to allow the bigger screws to clear (#891-116-177)=$3.21
1. Remove receiver from stock.
2. Remove barrel and all internals from receiver.
3. (Assuming the base is already on the receiver) remove only the two middle screws, leaving the base attached by just the two end screws.
4. Starting on the base side, use the 28ga bit to drill out the two vacant holes.
5. Tap the two holes all the way through the base and receiver.
6. Insert new screws into the newly tapped holes and tighten to ‘snug’.
7. Remove the other two original screws (leaving the new ones in place).
8. Repeat steps 4 & 5.
9. Remove the base from the receiver.
10. Now you need to open the holes in the base to allow the screws to spin freely. I simply put a screw in the holes (in the base only) and just stripped them out. You can use the 16ga bit if you’d prefer. Result is the same.
11. Replace base onto receiver with all 4 screws to make sure everything fits.
12. **With the ¼” bit and some trial and error, countersink the holes in the base so that the screw heads don’t stick up too far, and so that the screw ends just barely protrude down into the receiver (too far and they’ll bind on the bolt, not far enough and they won’t hold anything).
13. Remove everything again and thoroughly clean the receiver inside and out. Reassemble. Apply your favorite lube. Shoot.
Now you can actually tighten the base to the receiver with little worry of stripping. Ruger should have used 8-40 screws to begin with!
*This is for the standard Weaver T-09 base. If you have a Power Custom, or some other brand of base, your screw length (and corresponding Brownell’s number) may differ.
**A standard drill bit will not exactly match the angle on the Weaver screws, but its close enough considering that your using a steel screw to mate 2 aluminum pieces. If you can find a bit that exactly matches the angle, go for it.
Also, the ¼” is just an approximate size, the one I used was actually 15/64” because that’s what I happened to have on hand.