doublegunshop.com - home Forums General Discussion German & Austrian Sporting Guns @ doublegunshop.com SKOPAR B scope

I agree with the idea of fire forming with a 6.5 x 55 case and fast burning powder to get the the best fill out. I also agree that you shouldn't buy any headspace gauges at this point, due to the cost and the fact that they may not be what you need, and you may never use them again. Another option to see if you may have an excess headspace situation would be to cement round pieces of thin plastic shim stock of various thicknesses to your 6.5 x57 cases to see how much makes it difficult or impossible to close the bolt. It doesn't take very much to cause excess case stretching, or partial or complete head separations. At this point, it is impossible to know if you are dealing with an obscure standard chambering, a wildcat, or an over polished chamber. Here's a silly question... any chance of contacting the original owner to get some clues?

I'd still recommend slugging the bore too. And another chamber cast with very careful measurement at the correct time after casting is a good idea. You already have the materials.

If chambering a rifle for a caliber I don't have access to headspace gauges for I sometimes use a factory cartridge with one thickness of tape on the head for a go gauge and enough thicknesses to make the normal difference between the gauges for the no go( usually .003 or .006"). I usually use masking tape because it is "on hand" and easy to trim to fit the head. The same idea as Keith's, different material ( this is a "make do" solution, not the preferred one). Be sure the cases you to fire form with a European case rather than a smaller American one.
Mike

It is Norma brass.

I will try the masking tape trick first.
I have some Bullseye powder on hand. How much would I need to use to fire form or to see if this case moves much? I have seen 11-11.5gr mentioned to fire form .260.

when using the tape to check headspace do I feed from the magazine?

R.Marshall
No, don't feed it from the magazine. It is preferable to remove the extractor( you don't have to remove the retainer, just have a scribe handy to turn it around if necessary to remove the bolt). You can slide the case under the extractor by hand, you just lose some sensitivity of feeling( the tape is somewhat compressible so don't "crush" it closed). The Bullseye load should work. Tamp a quarter sheet of toilet paper over the powder, fill the case with polishing media/corn meal/ grits/or cream of wheat and plug it with toilet paper/ foam/ wax/ etc. If it doesn't fill out the case, increase the powder. Avoid using a bullet with any significant amount of Bullseye.
Mike

RM, When you fire a case-forming load, don't have the muzzle near anything you don't want damage. High velocity corn meal is more serious than it sounds.

well I fire formed a pcs of 6.5x55 norma brass with 11gr of Bullseye and coffee and a pcs of cotton ball for plug. The primer is slightly bulged.

unfired brass in inches
base .4760
shoulder .4325
bottom of neck .2950
top of neck .2930
lenght .215 60

fire formed brass in inches
base .4760
shoulder .4550
bottom of neck .3080
top of neck .3025
lenght .214 95

Original cast with cerrosafe in inches after cooling
base .484
shoulder .457
bottom of neck .311
top of neck .300

original drawing of cast measurement in MM after cooling and where my measurement were taken on brass also

would it be interesting to fire form a .257 Roberts?

It seems awfully close to .257 Roberts AI going of the fire form brass but not a exact match.