Odd BBLs From Numrich

[sheepherder]

I git the 6 1/4" barrel in from Numrich today...I'm somewhat disappointed...

It may not be readily apparent, but the taper is quite 'fat' up where the shoulder is...More so than a 9mm or 7.65mm [100mm/98mm] barrel [first pic comparing 98mm/7.65 barrel to Numrich]...

The Numrich barrel measures .710" at a point 5/16" forward of the receiver flange surface...The Luger 7.65 barrel measues .620" at the same point...

I tapered a home-made 9mm barrel using 7.65 dimension at the barrel band and the point 5/16" from the receiver flange surface (IOW, a stretched 7.65mm taper)...That's it [second pic] compared to the Numrich barrel...

While my homemade tapered & stretched barrel is no show winner, IMHO the profile is much more esthetic than the Numrich barrel...

I don't see why the Numrich barrel was made so 'fat' at the rear...

The 7.65 Numrich chamber is 'sloppier' than my Clymer-reamed barrels...Lot more 'wiggle'...Thread stub is right-on in length and diameter...Bore looks OK...

Flange/shoulder is artillery thickness; not 98/100mm thickness...Numrich front sight band diameter is .008" greater; flange dia is .020" greater; end of taper in front is .018" less...

The dimensions on the Numrich barrel don't equate to anything I have here...In 7.65 or 9mm...Even the 6 1/4" OAL length is odd...

I suspect I'll probably end up re-tapering it...So that it has a 'stretched 7.65 barrel' taper, like my barrel in 2nd pic...

Another Numrich mystery...

[Olle]

Another Numrich mystery for sure...

Whatever it is, I guess it's still better than starting with a blank. The chamber is a bummer though. Is there enough meat on the flange to cut back, so you can deepen the chamber?

[sheepherder]

Originally Posted by Olle

Whatever it is, I guess it's still better than starting with a blank.

It was cheap enough to be worth a shot. It beats having to cut away all that steel to get down to the profile I want. It'll just be 5 or 6 taper cuts now.

The chamber is a bummer though. Is there enough meat on the flange to cut back, so you can deepen the chamber?

I won't bother. It may well be within tolerances, especially for military use. Clymer reamers are typically .002" over SAAMI case dimensions. That's way under specs for military. I don't really have any way to measure this chamber directly. No matter. I won't be shooting hot loads.