Broke screw

I needed to change a scope on my muzzleloader to a better scope,and mounts and one of the screws, must have been slightly defective, broke off in the barrel. It is a Knight Vision rifle with split bases. Does anybody make a rail base to fit a Vision? I would feel better with three screws in a long base rather than the split base. The gun shop tried to drill it out, but couldn't even dimple the screw. I went to a machine shop and got a couple of the best bits they have and they wouldn't touch the broke screw.

Was the rifle clamped onto a drill press and they could not drill the screw out??  I can drill just about anything.  I've never seen one that couldn't be drilled out.

No, rifle in a gun vise using a Makita drill. Down here I don't know of a gunsmith that is equipped with a drill press for a rifle. The guy at the local gun shop said it was the first for him.... I might have to ship the rifle to someone.

Your machine shop should have a drill press.  I don't think you'll ever get it with a hand drill, without damaging the barrel.  You certainly don't want to mount with only three screws.  

I had that happen once, I tried drilling it out with a regulr drill bit and it didn't work, so I did the most retarded thing ever, I pushed down harder on the drill with all my weight - of course the drill bit broke and the drill (with it's broken bit) danced along the top of my brand new Conquest 3-9X40 - It looked like it was hit with a German 88mm flak round!  Bought a carbide tip drill bit and blew right threw it with no problem, guess I should have done that first!  

Edited by bricat - November/28/2009 at 00:39

Few gun shops have a gunsmith. I never let a guy at a gunshop work on any of my firearms. I want a gunsmith that knows what they are doing. Be sure to torque your screws properly. Tractor tight is over tight.

Before ever going into a machine vice I would try this; get a suitably small prick punch. Tap a small detent in the top of the broken screw. Then, tap at an angle in the CCW direction. This should back the screw out unless it is bottomed out tightly, has been burred over by previous attempts or the screw is broken off deep inside the tapped hole.

Timbercruiser,

Dremell makes some diamond coated bits for a dremell tool. If you can cut a slot in it you might be able to get a small screwdriver on it. Use liquid wrench  and use heat from a torch.

Edited by Urimaginaryfrnd - November/28/2009 at 21:20

I don't know if I want that much heat on a rifle barrel, but I'm not a metallurgist......that question is for Dale. The liquid wrench may help though. A good carbide left handed drill bit in a drill press may be the ticket. Sometimes the bit trying to cut while turning left is enough to turn the screw out.

Edited by trigger29 - November/28/2009 at 21:22

I would think it could take a little heat which if there is locktite involved might make a difference but err on the side of caution and go to the gunsmith.  Anyone who doesnt have a drill press and a lathe is probably not a real gunsmith.

Urimaginaryfrnd wrote: I would think it could take a little heat which if there is locktite involved might make a difference but err on the side of caution and go to the gunsmith.  Anyone who doesnt have a drill press and a lathe is probably not a real gunsmith.

A little heat to break loctite is probably ok, I didn't think of that. And +1 on a real gunsmith having the correct tools.

Thanks for all the replies. I think I will try to contact the two people that HuntMaster recommended unless another competent gunsmith pops up closer by. It isn't but about 150 miles up there.

      You need to find a 'smith or a machine shop that has a mill. Milling these things out using a small carbide end mill bit is the best way to go.

Kickboxer wrote: Was the rifle clamped onto a drill press and they could not drill the screw out??  I can drill just about anything.  I've never seen one that couldn't be drilled out.

Ed Connelly wrote: Kickboxer wrote: Was the rifle clamped onto a drill press and they could not drill the screw out??  I can drill just about anything.  I've never seen one that couldn't be drilled out.   You could shoot it out with your 458 Lott........

There are machine shops that have EDM machines that can remove broken bolts and screws. This electronic discharge machining process is what Magna Port uses to drill holes in rifle barrels for porting. If you used red Loctite on these screws it's listed as permanent, even in large bolts and screws. Heat has to be used to break the red Loctite down. I have seen threads stripped from 1 inch and larger shafts when trying to take the nuts off without heat. 

Call me kooky, but wouldn't it be cheaper to drill the old screw out with a carbide bit and just buy a new ring???