Drilling small ring mauser gas escape hole

[HankC]

Building a small ring mauser sporter and bolt does not have a gas escape hole. Spanish 1916 has escape hole at the bolt flat area and vent thru receiver at the left side. Swedish M96 has escape hole on the right top of the bolt and vent directly to the air. I think most M96 has the hole before the extractor collar but I think I have seen picture that the hole is after the collar. Does it matter? It would be easier to just drill a hole vent to air directly and material after collar propabably thinner too. Any reason why Spanish chose to vent thru receiver? Most modern rifles do it this way also. Or, I can drill couple big holes like 98 mausers.
Now I have several receivers and bolt bodies to build from, I think I will build on 1895 Chilian that has a rear tang 3rd lug. It may not do much as a recoil safety lug, but still something.

 

[rcmodel]

I don't think it will do much good wherever you drill it.

Those actions don't have the 98's internal baffle design to keep escaping gas from blowing out the rear of the action in your face along the firing pin & bolt raceway anyway.

Best bet is to use good brass and reasonable pressure loads so you don't blow one up in the first place.

If you simply have to hot-rod, get a 98.

rc

 

[HankC]

I am aware of 98 gas dam design but not sure what you mean by internal baffle design. Majority of modern bolt guns do not have the gas dam either. I have couple 98s and couple small rings, this small ring project is a 7.62x39 build, small ring serves well. The gas management on small ring is not as robust as 98 large ring, adding gas escape hole may not be as effective but still helps. Question is where to drill the holes to be most effective.

 

[JNewell]

Did you check Kuhnhausen?

 

[HankC]

Did you check Kuhnhausen?

Don't have the book.

 

[Jim K]

The best those gas escape ports do is to vent the small amount of gas that escapes from a pierced primer and goes back into the bolt. The vent allows it to get out without coming back through the bolt. If a case head lets go, no tiny vent hole is going to handle the gas; it will burst the receiver ring and/or come back along the bolt raceways and into the magazine well, injuring the shooter and blowing the magazine and stock.

Jim

 

[JNewell]

Other issues, beside whether or not it would prove anything - you probably will have to spot-anneal the receiver ring. I don't know whether you're set up to do that and have the experience that +/-45kpsi warrants? That's a question, not an accusation.

 

[kaferhaus]

Gas, just like water will flow to the point of least resistance the fastest. If you're determined to do it I'd put it where the spanish did. You don't need to spot anneal the hole location. Brownell's sells a carbide spotter drill bit that will get through the outer "hard" part of the receiver ring.

I know the Spaniards re-barreled these to 308 and while I've never heard of one blowing up I sure wouldn't surpass 45K psi out of one.

 

[Jim K]

That receiver is not very hard and shouldn't require a carbide drill or annealing . Just make sure the port in the bolt lines up with the port in the receiver.

Jim