sloppy drill and tap holes dangerous?

BCrecce

BCrecce

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Just picked up a bubba special surprise from a cgn'r. A 1946
chinese mauser reciever with weaver bases drilled completely askewed from one another. My concern is the location and depth, holes drilled clean through intead of partial with a blind tap.

The forward most hole clean through is also over the barrel threads (threads showing at bottom of hole) would this last hole be safe for pressure?

Both action screw have been marred/stripped with the wrong screws. Should I just attempt a 1/4"x20 tap with matching screws?

Thanks, Ash
 
wasnt too thrilled to find out it was a chinese receiver, from what have researched arsenal 21 was done on german 98 tooling with postwar good steel. no rough machine marks like my norinco shotgun. Bolt body looks to be german turn down with a miriad of mix n match parts on it.

Barrel is supposed to be a newer medium profile 308 and a timney trigger in a butchered target stock, look to be the only salvagable items in the mix.
 
IMHO, there isn't a lot to be concerned about as far as safety goes with a Chinese 98 action rifle. They were built under German/Czech supervision on their equipment. Their parts even interchange with European made models.

As far as the oversize holes go. If there is enough meat there to go to the next size tap after you've drilled out the existing threads, again no problem.

As far as scope base holes going all the way through, if they go through the receiver and through the barrel shank into the chamber then it's time to swap out the barrel or again, if there is enough metal left and if the barrel is worth saving, set it back and rechamber it. Most receivers will have the holes drilled all the way through the receiver ring without the barrel being in place when the job occurs. This usually only happens on older rifles or surplus firearms.
 
bearhunter said:
IMHO, there isn't a lot to be concerned about as far as safety goes with a Chinese 98 action rifle. They were built under German/Czech supervision on their equipment. Their parts even interchange with European made models.

As far as the oversize holes go. If there is enough meat there to go to the next size tap after you've drilled out the existing threads, again no problem.

As far as scope base holes going all the way through, if they go through the receiver and through the barrel shank into the chamber then it's time to swap out the barrel or again, if there is enough metal left and if the barrel is worth saving, set it back and rechamber it. Most receivers will have the holes drilled all the way through the receiver ring without the barrel being in place when the job occurs. This usually only happens on older rifles or surplus firearms.
Click to expand...

Laugh2
 
6-48 is the most common base screw size, next up is 8-40 I believe.
I'd get a smith to check it over before doing anything though....sounds homemade possibly.
 
^ yes I will be dropping off with a smith for a headspace check and see what kind of weaver/picatinny base could be fitted now, hopefull be able to reuse a couple of the holes on top.
 
BCrecce said:
Just picked up a bubba special surprise from a cgn'r. A 1946
chinese mauser reciever with weaver bases drilled completely askewed from one another. My concern is the location and depth, holes drilled clean through intead of partial with a blind tap.

The forward most hole clean through is also over the barrel threads (threads showing at bottom of hole) would this last hole be safe for pressure?

Both action screw have been marred/stripped with the wrong screws. Should I just attempt a 1/4"x20 tap with matching screws?

Thanks, Ash
Click to expand...

Have you ever seen a drilled and tapped rifle before? I have never ever seen one that isn't drilled and tapped right through. Every single new rifle on the shelf is drilled exactly as you describe, though they are generally done straight.
 
Receiver holes are commonly drilled all the way through the receiver where you would see the barrel threads. If u didn't see barrel threads I'd be concerned because the hole was drilled through the chamber. (Which would blow your scope right off your gun, at best)

The chinese made receiver itself is not unsafe unless it sustained fire damage at some point.

1/4x 20 is WAY too big for a sight base screw hole, you most likely just need to go to a 8x40 which is standard. Or worst case a 10x 40. Still almost half the size of a 1/4x 20.

You mentioned it's a bubba, don't make it worse! :p
 
The front and rear receiver screws were probably 1/4-22. If they are stripped, running a 1/4-20 in isn't going to help.
I would clean them out with the correct tap, see if that helps.
 
Was under the impression m98 trigger guard/action screws were metric, the screws someone jammed in there are what appear to be 1/4x20 and and the front appears to be an old imperial or british thread. Hard to tell from the marring, both screw wobble around when in. Found an easy solution to the weaver holes on top, a leupold one piece base seems to cover old holes and space far enough away for new ones .
 
BCrecce said:
Was under the impression m98 trigger guard/action screws were metric, the screws someone jammed in there are what appear to be 1/4x20 and and the front appears to be an old imperial or british thread. Hard to tell from the marring, both screw wobble around when in. Found an easy solution to the weaver holes on top, a leupold one piece base seems to cover old holes and space far enough away for new ones .
Click to expand...

Nope - Standard M98 receiver action screws are 1/4-22 with a 55 degree angle...don't ask me how i know this.
 
Once again I prove to be my own worst enemy and somehow read you wanted to make your scope base screws 1/4x 22, yikes....f:P:

Good luck with the fix!
 
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