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Drill/tap 870 receiver + de-ribbing barrel

4K views 4 replies 4 participants last post by  rsm688 
#1 ·
I am about to drill and tap my receiver on my 870 for a rail and wanted to know what depth to drill and tap as I dont know the thickness on the top of the receiver and also what diameter screw you guys reccomend, I was thinking a #6 or #8.

Also, I am thinking about deribbing my barrel and was wondering what the best way to do so without damaging the barrel (dont care about the finish), I slid a screwdriver under the rail on the piece of barrel I chopped off and one wack with the hammer and it popped off but it left some rough spots where it was soldered on. I was thinking heating it with a mini torch and then using a screwdriver and hammer to knock it off. Any thoughts?

Thanks,
Spencer
 
#2 ·
The hole can go all the way through as long as you clean up the burr inside after you tap the hole. As long as the screw does not interfere with the bolt it will be fine, The more threads you get a screw into the stronger the unit will be. As far as diameter goes that will depend on your holes in your rail and what you plan to mount on it. Smaller screws are easier on the eyes if you plug them and make it a regular shotgun to sell someday. Larger screws are easier to tap and fit a good driver bit in. The larger tap is less likely to break than a smaller one.
The rib can be sweated off with a torch at pretty low heat but you will ruin the blueing. If this is a "Tacticool" gun you are probably going to paint or coat it anyway so a wire wheel to remove the last of the silver solder won't be a problem.
 
#3 ·
use a #31 drill and tap it for 6-48.....never start with the largest possible hole...if there's ever a problem with one of your threaded holes, you can go to a first oversized 6-48 (146-48 is available from Brownells) and then even to 8-40....be sure to zero the jaws in your drill press or mill vise and you can find center with an edge finder.....once finding the edge, just add the diameter of the edge finder to the width of your receiver and divide the sum by 2.....then you know how far to move your table to get to the exact center. In an 870, you can drill all the way through if you want to....a #62 Weaver mount works very well on Remington receivers - as it matches the receiver's top radius.....by the way, that rib cannot be "sweated" off, as it is not soldered, but rather fusion welded to the barrel.....the best way to break the welds might be to cut on each side of each rib post and twist each post with a wrench....the weld should snap easily.
 
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