8mm barrel grove diameter?

[Char-Gar]

I just slugged an 8 X57 mil-surp Mauser and found it to be .325 X .3105. This was not muzzle nor throat, but barrel mid-point. What do you guys find to be about the norm?

[Larry Gibson]

I just slugged an 8 X57 mil-surp Mauser and found it to be .325 X .3105. This was not muzzle nor throat, but barrel mid-point. What do you guys find to be about the norm?

All of the 4 M98 8mms I have these days have throats of .325-.326". The throats are long and I like the Lovern Lyman 323470 and 323471 bullets (though I have the GB 175 gr bullet but it is yet untired). The 210 gr 323471 sized .325" and seated so the GC is just at the base of theneck has the driving band just kissing the lands. Thus there is a large portion of the bullet fitting perfectly in the throat prior to firing. Quite frankly the 323471 is themost consistantly accurate cast bullet I have. I believe the reason for this is this perfect fit in the throat. Tith the one M98 I have with a scope on it MOA groups are the norm.

I long ago quite slugging the bores. It is the throat that the bullet must fit or be slightly larger than for best accuracy.

Larry Gibson

[NVcurmudgeon]

I have had a well-worn 1933 Obendorf, an excellent VZ24, and a new Yugo 48 pass through my hands. All slugged .324" +/- .0005", so I bought a .325" Lyman sizing die and never looked back. They all are capable of shooting within the limits of FDR's first term eyeballs abd Mauser barleycorn sights.

[mooman76]

I have a G43 and a M48A and they slug .323 and .324.

[mhb]

In most good-quality rifles run no larger than .325" - HOWEVER: the Turk M38 rifles are a different animal, running from there up to .330" ( I know because I measured a good many of them), but, with proper bullet selection, can shoot quite well, assuming the barrel and the rest of the rifle are in good condition. It also goes without saying that you need to measure the groove diameter of any rifle you plan to shoot cast bullets from.
mhb - Mike