Jump to content
Military Firearm Restoration Corner

Short Camberred Barrels


Hanksv

Recommended Posts

I have been lurking around here as I gather information for my first mauser build. I'm starting with a Yugo 24/47 and I'm going to make it into a 308 win. I recently bought a short chamberred adams and bennett F34 barrel for this project. Midway has had them backordered forever, so I picked one up on gunbroker for a little bit over the midway price.

 

I don't have headspace gauges or a finish reamer yet as I'm still not sure if I will do that part of the project myself. Anyhow, out of curiousity I dropped a round of surplus 7.62x51 NATO into the chamber to see how short it really is. I expected that the case wouldn't protrude very much since they say that these things are only cut .050 short, however, the case sticks out a good three quarters of an inch or more (I didn't bother to measure). This doesn't seem right, but then again, I haven't done this before. Are the dimensions of the NATO and the commercial ammo that much different? I always thought you could 7.62x51 in a 308 Win., but not the other way around. What do you guys think?

 

Thanks,

 

Hank

Link to comment
Share on other sites

Something isn't kosher. I would expect protrusion more on the order of 3/16 than 3/4. Are you positive the barrel is a .308 Winchester? Could it have been a 7.62x39?

 

Clemson

Link to comment
Share on other sites

Well, I just checked an A&B 30-06 barrel, and a factory loaded round only sticks out about .150". However, there have been some I have done where the case stuck out a good 1/2" or better. I believe the .050" refers to only the length. Since the cases are tapered, and the chamber will be undersized all the way around, that may cause the cases to stick out more.

Link to comment
Share on other sites

  • 2 weeks later...
So I finally got my hands on a go gauge and dropped it in there. It sticks out about .3 inches. Probably won't take much reaming to finish that off.

 

A go gage protruding .300" is a long way, especially if these are sold as being .050" short. that's six times the distance advertised.

 

Being as the throat is not been cut, I have to wonder if these are chambered with a pilotless reamer. Winchester used to use pilotless reamers, it speeds up production.

 

Link to comment
Share on other sites

A go gage protruding .300" is a long way, especially if these are sold as being .050" short. that's six times the distance advertised.

 

Being as the throat is not been cut, I have to wonder if these are chambered with a pilotless reamer. Winchester used to use pilotless reamers, it speeds up production.

 

 

I spent almost three hours reaming this barrel the other night. Couple turns, clean barrel, clean reamer and repeat. I'm down to where the go gauge is at .138. It didn't take too much reaming to get the gauge to drop to .14, but quite a bit of reaming to get it to start going deeper. Initially it looked like the cutting was happening just below the case shoulders - the gauge might have been hanging up because the taper of the chamber was a little tight. After that, it looked like the reamer was cutting the throat. I'm going to try to build a barrel vise and an action wrench Sunday or Monday. I'm not doing any more reaming until I get the old barrel off and take some measurements. I'm still trying to decide if I should lathe the safety breech on the barrel. If I went too far already, then the answer is yes. If not, I'm reluctant to create more of a reaming project for myself.

Link to comment
Share on other sites

  • 1 month later...

Short chambered A&B barrels are not just short chambered, they are narrow chambered.

A cartridge will stick out an inch.

 

It depends on how narrow the headspace gauge is.

 

I have two A&B short chambered barrels here, and the headspace gauge sticks out 0.3" on one, and 0.14" on the other

But a sized case sticks out 0.32" and 0.54" respectively.

 

Obviously, one chamber was cut deeper, but narrower than the other.

 

As long as the reamer pilot can reach the bore, it should be ok.

Link to comment
Share on other sites

If you start feeling impatience starting to flow, put it down and find something else to do. Chamber reaming should be done in a Zen-like tranquil state, or you risk chucking it up again in the lathe and cutting a new shoulder.

 

I hope I take my advice next time.

Link to comment
Share on other sites

With this stupid barrel I had to chuck it up in the lathe anyway. If I would have installed it without setting the shoulder back, it would have seated on the front of the receiver and wouldn't have been close to seating at the inner C ring.

 

I ended up spending most of a day reaming. I probably have to give the reamer one more turn, but I haven't messed with it in a few weeks. Right now the bolt will close on the go gauge, but it is fairly tight.

Link to comment
Share on other sites

×
×
  • Create New...