specweldtom
Well-Known Member
Learned several things about the 17-4 PH Walther barrel. I used a hi-speed steel parting-off tool and chamber reamer, and carbide turning and threading tools. Overall, the barrel had a "crunchy" feel and sound with either type tool, and the finish was not as smooth as 416 stainless barrels. The reamer is a fixed pilot .30 x .378 Wby finisher (Clymer) that had only cut 3 chambers. 40 rpm with my normal feed rate actually tore small chunks off the shoulder face and made a rough looking neck and body wall also. Tryed different speeds and settled on 63 rpm. Neck and wall finish were acceptable but the shoulder face was still too rough. By feeding only .025" deep between cleanups and slowing the reamer feed way down (enough to risk rubbing and work hardening the surface), the shoulder face was acceptable and the body wall actually got very nice. I have a Hawkeye borescope that I use to check the chamber appearance as I go. I only had "black magic" threading dope, so couldn't try different cutting fluids. There probably is something better.
This barrel took approx twice as long to chamber as a 416 barrel. Just over 7 hrs, in two sessions. I like the physical properties of 17-4 for a barrel, but am not sure yet that they warrant the extra work. This barrel also had the Blackstar treatment, and the bore is measurably oversize. With a G.I. .30 cal bore gage, I got .3005"-.301" land diameter, with a slight steady taper tightening toward the muzzle, thank goodness. Dave Manson recommended a replaceable pilot reamer because the fixed pilot would probably be too loose in the Blackstar barrel. He was right, but I had a .0005" bore runout setup, and decided to try the reamer (in a floating holder) anyway. My theory is that in a good concentric setup, the reamer will naturally try to center itself, also that the long Wby freebore in the reamer might help hold center. Must have worked, because with the Starret last word I measured .0007" on the belt cut ,worst case, and .0006" on the wall about an inch in, as far as I could reach.
This rifle is my own, and I unscrewed a good Hart barrel to try the Walther. I don't know enough about these barrels to put one on for anyone else, and I figured that the .30 x .378 on a Mk V action would be a good test for it.
Bottom line, quite a bit tougher to work than a 416 barrel, but if a mullet like myself can do it, a real 'smith would have no trouble at all. Now, to see if it will shoot well. I'm hoping for sub 1/2 moa, because I've seen it with Hart and Shilen barreled .30 x .378's.
This is long winded, but might help someone else thinking about using a Walther stainless barrel, with or without the Blackstar treatment.
Good shooting, Tom
This barrel took approx twice as long to chamber as a 416 barrel. Just over 7 hrs, in two sessions. I like the physical properties of 17-4 for a barrel, but am not sure yet that they warrant the extra work. This barrel also had the Blackstar treatment, and the bore is measurably oversize. With a G.I. .30 cal bore gage, I got .3005"-.301" land diameter, with a slight steady taper tightening toward the muzzle, thank goodness. Dave Manson recommended a replaceable pilot reamer because the fixed pilot would probably be too loose in the Blackstar barrel. He was right, but I had a .0005" bore runout setup, and decided to try the reamer (in a floating holder) anyway. My theory is that in a good concentric setup, the reamer will naturally try to center itself, also that the long Wby freebore in the reamer might help hold center. Must have worked, because with the Starret last word I measured .0007" on the belt cut ,worst case, and .0006" on the wall about an inch in, as far as I could reach.
This rifle is my own, and I unscrewed a good Hart barrel to try the Walther. I don't know enough about these barrels to put one on for anyone else, and I figured that the .30 x .378 on a Mk V action would be a good test for it.
Bottom line, quite a bit tougher to work than a 416 barrel, but if a mullet like myself can do it, a real 'smith would have no trouble at all. Now, to see if it will shoot well. I'm hoping for sub 1/2 moa, because I've seen it with Hart and Shilen barreled .30 x .378's.
This is long winded, but might help someone else thinking about using a Walther stainless barrel, with or without the Blackstar treatment.
Good shooting, Tom
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