7mm Mauser OHAUS Mold

[FabMan]

I have this OHAUS mold 28-168-S that I received
in a trade. Not much info out there on these molds.
I guess.RCBS bought them out. Do these mold numbers
relate to the RCBS molds and would this be a good
7mm Mauser mold?

[runfiverun]

http://www.midwayusa.com/product/222269/rcbs-2-cavity-bullet-mold-7mm-168-sp-284-caliber-7mm-285-diameter-168-grain-semi-point-gas-check

does it look like this one?
the numbers are still similar since rcbs uses 7-168-Sp as their designation.
I use it in one of my 7X57's at 286 diameter.

as to your mold fitting your rifle that's a maybe.
some of the older mauser rifles [milsurp] have throats bordering on 29 caliber and need a diameter more like 290 with a nose that almost groove diameter in a normal rifle.

[FabMan]

Thanks much,
it does look like the one on the website.
i have read quite a bit about bore slugging
and it is confusing/contridicting. Slug from the muzzle, from the breech, chamber cast, measuring the ID of fired cases. You would think the last 6 inches as it leaves the muzzle would be the most important?

[runfiverun]

not really.
the first inch from the case neck forward really is what you wanna know.
the rest of the barrel could influence what happens after that, but that's where it all starts.

[Adam Helmer]

FabMan,

I have a dozen old Military 7X57mm rifles and carbines. My most accurate cast boolit is the Lyman #287308, a 168 grain RN gas check boolit. I never slugged any throat or bore. I size the boolit .285", lube with Alox and make it out of old wheelweights and a dash of tin and drop it from the mould into a bucket of water. This boolit is also a fine one in my 7MM Remington Magnum rifles.

Adam

[blixen]

+1 with run5run on oversized bores. My 7mm Spanish sporter isnearly a .29 caliber. Shoots j-slugs great, but key holes .284 boolits.

[runfiverun]

I had one I couldn't shoot 175's in.
I walked within 10' of the target and barely kept it on paper.
the stock was nice the bluing looked nice the barrel even had rifling.
I wasn't casting for rifles at the time and had no idea what was up and traded it off.

[FabMan]

It's a Brazilian 1908 with a great bore. I guess I should run a slug from the chamber and out the muzzle and measure it that way? Or run it a little ways past the chamber and push it back out.My thinking is it should be 1-2 thousands larger that the biggest section of the bore? I want to slug it to at least get it on paper and not waste time experimenting.

[leadman]

The military Mausers generally had long leades, or throats in front of the chamber plus many were worn from use. This is normally the largest area of the bore. If the boolit is too small it can be cut by the powder gases and will lead.
I normally drive a slug in from the chamber end just past the chamber then back out. Then I will run another slug from the chamber end and pay attention to tight or loose spots on the way thru. I have had a slug drop out of the bore when it got close to the muzzle end. This is usually cleaning rod wear. Some may have been counterbored from the muzzle end to remove this.
Most of the many rifles I have slugged would have shot fine just matching the boolit diameter to the throat slug.

[FabMan]

Thanks for all the info. So yes, it does make sense to slug just front of the chamber. That should be the largest diameter unless the muzzle is worn. If my mold isn't large enough I will try to open it up with some polishing compound. I read you can make a cast, roll it in some abrasives and spin it in the mold.