21 March 2015, 21:31
speerchucker30x378SKS Bolts
I don't know about you guys in the USA but I see a lot of SKS rifles here that the guys want to get converted so that the clip can be inserted and removed with the bolt in the forward position. If this is not done, some clown will inadvertently try to pull one of the aftermarket, plastic mags out or push it in without having the bolt back and break the feed lips off the mag.
The job is actually pretty easy to do but requires some tooling to do. I found that a 3/4 inch 90 degree carbide snag with disposable inserts and a 45 degree carbide snag with disposable inserts work best. It can be done with regular carbide tooling but the material is pretty brutally tough and hard. It's best to use disposable insert tooling.
I lock the bolt in the vise and find center and then cut each side at about 800 RPM down to make the bottom of the bolt .480 in width. That seems to clear every feed lip setup I have encountered so far. Then I run a 45 degree cutter down each side to give a 1/32nd 45 to guide the feed lips if the clip sits slightly to one side or the other.
You don't want the nose of the bolt to be altered in any way. Or, at least very little as that area controls the feed. It will also leave leave a slight T, or edge where the rail used to be and I break the edges of that with a diamond file to keep it from snagging the feed lips when you pull the clip out.
When I'm done I wire wheel the snot out of the bolt to remove the burrs and blend the finish and toss everything back together. Time for the job including booking the gun in and out is about 2 hours to 2.5 hours man & machine, depending on what sort of hermaphroditic stock he has on it . I charge $150 to do it which also covers the cost of insert replacement.