Another barrel question.

Going through my barrel stash cleaning up old stuff. Found a blank that is a 12 groove .375. Narrow lands, excellent barrel quality. No markings of any kind, but it has been chambered and faced, so might have been marked at one time.

Who might have made this one?

dave

Dave this sounds a whole lot like a 308 I have. 11 lands and 11 grooves, no makers mark anywhere. No symbols of any kind, no little dimples, nothing. Somewhere I have a bullet I recovered from wet paper and the rifling marks look just like those from a 375Win bullet recovered after being fired in a Marlin Micro groove barrel. Jeffeosso once suggested I contact Pac-Nor as they might have done a special run of 11 groove barrels. So Far I am still clueless.

Andy

Is the barrel threaded already? Are the lands and grooves equal size?

How many lands/grooves are there in the Marlin "Micro-Groove" barrels? They chambered the 336's in 375 Winchester caliber years ago.

Ruger 375's and 458's had micro-Groove barrels. At least the No. 1's did.

Marlins have 12 groove barrels; this is NOT the "Micro Groove" barrels on Marlins from the 60s, even though they are still marked as such. True micro groove barrels have about 20 grooves, really small and shallow. Nothing like the recent 12 groove barrels, which are conventionally rifled.

This one is an unthreaded blank, 1 1/4 inch nominal diameter. Someone prechambered it for .375 H&H but didn't thread it. I'd just never heard of a maker selling 12 groove blanks, thus the question. I'll check the twist, and if appropriate, set it up and see how it shoots. Unfortunately, it's only 24 inches overall, so can't really set it back and chember to something else without getting down to 20 inch finished length or so.

dave

quote:

Originally posted by ssdave:
This one is an unthreaded blank, 1 1/4 inch nominal diameter. Someone prechambered it for .375 H&H but didn't thread it. I'd just never heard of a maker selling 12 groove blanks, thus the question. I'll check the twist, and if appropriate, set it up and see how it shoots. Unfortunately, it's only 24 inches overall, so can't really set it back and chember to something else without getting down to 20 inch finished length or so.

dave

Don't know if you'd have to crop it 4" to rechamber. 376 steyr would only have to be set back about a 1/2" or so.

I was actually thinking I'd like to chamber it to something smaller, like .375-06 or .375 x 2.5 nitro express. To do that, I'd lose an inch at the muzzle in finishing, and 2 1/2 inches of chamber to get it small enough. Nothing wrong with the .375 chamber, I can thread it for an action and then just finish ream it if needed, so won't really lose any length other than cutting some off the muzzle.

I checked the twist, and it appears to be 14 twist. Using a patch on it cleaned out the grease and the barrel is very nice quality, smooth and consistent throughout.

dave

Heck if its a 1-1/4 blank it can be cut down and rechambered for 375x600OK 2.5". a screaming wildcat I'd like to see!

Numrich arms sells barrels and blanks with all kinds of groove patterns in them, that they get as over-runs from manufacturers. I have a .429 barrel right now with 12 grooves, which came from them and they didn't make it. Make sure it is a 4140 steel barrel and not one originally intended for a 38-55 made out of 1117 or something like that, before you chamber for something giving 50Kpsi.