Speaking of headspacing surplus rifles

[Janos Dracwlya]

My learning experience with my Ishapore No. 2A has left me wondering about checking the headspace in rifles made in the less common calibers: if I can't find a headspace gauge in 7.62x51mm, what am I going to use to check the headspace in a Steyr-Mannlicher M-95 in 8x56mmR or a Schmidt-Rubin K-31 in 7.5mm Swiss? Any thoughts?

Thanks.

 

[Beetle Bailey]

Well, I just bring it to my local gunsmith and have him check it out for me. Then I'll buy something in his shop (ammo, cleaning supplies, etc.) as a "thank you."

 

[Janos Dracwlya]

That would be my solution, except for the fact that we don't have any gunsmiths who do that kind of work around here, with the exception of a guy who is elderly and semi-retired and only does work for friends. Of the other two smiths I know, one is really great at installing sights and building custom Colts, but knows little about surplus guns, and the other seems to be on the dishonest side, so I would not trust him to work on my guns.

However, I would rather know whether a gun is worth buying before I buy. I know that most mil-surps run under $200, but that's not small change for me.

 

[R.W.Dale]

A lot of people tend to stress over headspace changing on a rifle more than they should. Headspace on a rifle is kinda like fuses on your car. They just don't go bad without a reason. In other words if a rifle was issued 40 yrs ago and then depot for storage and then sold a surplus it'll still have the same headspace it had when some recruit was qualifiying with it 50 yrs ago.

But if you're worried there are a couple of low buck methiods to check headspace.

1. The tire and string methiod. Pretty simple tie the rifle to an old tire and shoot it with a string. Eject the case and measure it with some calipers checking for excessive strecthing.

2. The cream of wheat and Unique methiod. A little more specialized, A buddy bought a springfield sporter that had no caliber markings on it other than the price tag that said .300 wby. He bought the rifle only to fnd out that my 300wby dummy round wouldn't chamber??? Well the bore measured .308 and the chamber was cut for a belted magnum but is it a .308 norma mag or a 300 win mag???

So what I did was to take a shorter 7mm mag case primed and charged with I believe 8grs of unique, I then topped the case off with cream of wheat and seald the affair with some wax. Apoun firing the 7mm mag case fireformed to the chamber allowing me to get some measurments and determine that the rifle was indeed a .300 win mag.

 

[jaimeshawn]

For cartridges that reference on the shoulder, like 30-06 or 8mm mauser, or 7.5mm Swiss, place one piece of masking tape on the base of an unfired 7.5 Swiss cartridge and see if it chambers. (It should). Place a second piece of masking tape on the base and it should be very difficult to chamber. Place a third piece of tape and it should be impossible. Masking tape is about 0.004" thick.

If a rifle headspaces long, consider if you would be willing to handload for it. I had a BSA 30-06 that was at least 0.015" long that still had great rifling and shot great. I just couldn't burn factory ammo in it.

For rimmed cartridges like 7.62x54R, 30-30, etc, the base references the rear of the cartridge so they are very tolerant of headspace. The thing that makes excessive headspace dangerous is that if a cartridge fires when the base is unsupported by the bolt, the brass is too weak to support the pressure alone and will rupture, sending hot gas into your face. A rimmed cartridge always has the base supported by the bolt, so a few extra thousandths ahead of the cartridge are OK.