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Post by Gunny268 on Dec 11, 2023 13:48:21 GMT -5
I went to the local gun show this weekend and an acquaintance asked me to take a look at his revolver. He brought it over today. Ruger OM 357 with a 1957 serial number. No loose sights, and an excellent trigger. B/C gap feeler gaged at .005. Cylinder throats pinned at .358 (minus pin gages). Has some end shake (but I've seen worse that shoot ok). Only 1 round hit an 8" paper plate at 25 yds. Fired 5 rnds of Rem 357 / 125 gr SJHP from a steady rest. Suspect this might be the problem and wanted to bounce it off you guys before I talk to him again.   |
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Post by Encore64 on Dec 11, 2023 13:50:17 GMT -5
Rough, I've got an extra barrel 6.5" if he needs it...
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Post by Gunny268 on Dec 14, 2023 13:37:34 GMT -5
Thanks Encore but I actually found two OM 357 barrels in my Ruger parts "black hole" box.
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Post by x101airborne on Dec 15, 2023 16:29:55 GMT -5
Thats about as bad as Ive ever seen.
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Post by bula on Dec 16, 2023 9:12:53 GMT -5
Get a bigger paper plate ? Kidding, attribute issue to the forcing cone ?
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Post by Gunny268 on Dec 16, 2023 13:04:49 GMT -5
Not sure. That's why I threw the question out here with a pic of the forcing cone. Am going to try to slug (and pin gauge) the bore this weekend (if I have time).
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Post by bula on Dec 16, 2023 13:08:26 GMT -5
A backer, to the paper plate ? As in, is there a group, but off the plate ?
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Post by z1r on Dec 16, 2023 14:22:22 GMT -5
A backer, to the paper plate ? As in, is there a group, but off the plate ? Yes, this. I've wasted a lot of time trying to diagnose problems when I wasn't printing on a target. Then I figured out that a large backer will help you to see where the bullets are actually hitting, and, more importantly, whether they are grouping or randomly scattered. |
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Post by bradshaw on Dec 16, 2023 14:30:54 GMT -5
I went to the local gun show this weekend and an acquaintance asked me to take a look at his revolver. He brought it over today. Ruger OM 357 with a 1957 serial number. No loose sights, and an excellent trigger. B/C gap feeler gaged at .005. Cylinder throats pinned at .358 (minus pin gages). Has some end shake (but I've seen worse that shoot ok). Only 1 round hit an 8" paper plate at 25 yds. Fired 5 rnds of Rem 357 / 125 gr SJHP from a steady rest. Suspect this might be the problem and wanted to bounce it off you guys before I talk to him again. ***** gunny268.... forcing cone appears specially cut to rip a bullet! Appears there is a sharp shoulder at the beginning of the lands. To insure a smooth transition from cylinder to the rifling, the transition of cone to the lands & grooves must be smooth. A choppy transition attacks the dynamic integrity of the bullet. The forcing cone is the only aspect of REVOLVER ACCURACY with the power to “correct” up to .006 or ..007” chamber-to-bore misalignment. (The overrated CROWN ranks very low in the orchestra of a revolver’s accuracy.) Aproper forcing cone compensates; a lousy forcing cone multiplies a lousy launching environment. Proving the bore & groove are uniform and not oversize, devoid of tight or loose spots, it wouldn’t be a bad idea to: 1) Lathe-turn the barrel shoulder to a depth of one or two threads (one thread may do). 2) I would time the barrel to hand tighten 10-12 degrees BTDC (Before Top Dead Center). 3) Lathe-cut forcing cone .160 to .200” deep (from barrel face), 11-degree included angle. 4) Face barrel for desired cylinder gap. (Barrel-cylinder gap affects velocity, not accuracy). All of which raises another question: have you slugged the bore? Any take-off barrel of less than demonstrated accuracy should be SLUGGED David Bradshaw |
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Post by bigbore5 on Dec 17, 2023 9:09:18 GMT -5
^^That.
Id just set the barrel back, but I have a machine shop at home and the skills to do it.
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Post by eagle1899 on Dec 17, 2023 12:17:40 GMT -5
Different barrel or setting that one back with a proper throat would be ideal.
Maybe a good candidate for Taylor Throating?
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Post by x101airborne on Dec 17, 2023 17:32:05 GMT -5
A hand reamer would cut that out. Kits are available from Brownells or most gunsmiths have them. Forcing cone can be cut without removing the barrel. "Then" if it didn't work, replace the barrel.
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Post by hunter01 on Dec 18, 2023 20:03:21 GMT -5
A hand reamer would cut that out. Kits are available from Brownells or most gunsmiths have them. Forcing cone can be cut without removing the barrel. "Then" if it didn't work, replace the barrel. THIS^^^You can buy the tools to do this job by hand for less than it will cost to send it out. A lathe cut forcing cone will have no advantage over the hand tool method with the proper pilot. |
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Post by bigbore5 on Dec 19, 2023 4:16:48 GMT -5
A hand reamer would cut that out. Kits are available from Brownells or most gunsmiths have them. Forcing cone can be cut without removing the barrel. "Then" if it didn't work, replace the barrel. 4D also rents kits to do it. It's a pretty simple job. Just cut the minimum you can to clean it up, then test fire. |
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Post by Gunny268 on Dec 29, 2023 21:23:54 GMT -5
I'd like to closeout this thread so nobody's left hanging. I gave Cooper his pistol back just before Christmas and suggested that he explore the following options...
1,) As David advised...
a.) Find a good smith to set the barrel back and recut forcing cone/reface barrel for gap.
b.) Find a good smith and I'd give him one of my good take off barrels, in exchange, to rebarrel the gun.
And finally, as BB5 advised...
c.) Find a good smith to recut the cone.
I also felt obligated to stress the following facts to him. "I've never done it. I have neither the skill nor the tools." He's a good and longtime friend and I certainly don't want to sour the relationship.
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