5-Shot Conversion - Documented

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Lee Martin

Hunter
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Dec 18, 2002
Messages
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Location
Arlington, Virginia
I started documenting a 5-shot conversion on my forum and thought the Ruger crowd may be interested too. Just like my OM .44 Special and Buffalo Seville, I'll cover each and every step in doing one.

As I've gotten older, I've fallen out of love with barrel bands on revolvers. Used to adore bands, but now my eyes don't take to them. Plus my preferred barrel length on Blackhawks is 6.0". The conversion will be the sister gun to this .500 Linebaugh:



The differences will be:

1) 6.0" straight taper barrel
2) Frame window opened 0.060"
3) Recessed cylinders (not a huge fan of them, but will do so here)
4) Jack Huntington Bisley mod with walnut panels

I'll discuss and photo document every step. From fitting an oversized bolt, milling the frame window, adding a stronger gate spring, making the cylinder, pawl and hammer/bolt timing, ratchet geometry, line indexing vs. line boring, heat treating, centering the barrel and cutting the cone, and making the front sight. It may take a week or two to get started, but it's coming. This first post is a placeholder....if it goes on the internet, I'm committing to the article. I hope folks find it informative.
 

Lee Martin

Hunter
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Dec 18, 2002
Messages
2,313
Location
Arlington, Virginia


First I fit the Bisley gripframe to the donor gun. I'd like to get this to Huntington to allow time for the reshape and wood carving. We'll use a spare Bisley frame as a mock-up during the build.

I started with your basic stainless conversion kit:



I won't inundate you with pictures on how to fit these. Many of you have done this yourself. As we all know, Ruger ships the frames oversized. Mating them to the frame entails bolting it up, marking the high spots, and a lot of filing and sanding. For those that haven't done this, here are the main areas to focus on:



I went real slow, filing the overhang, assessing it against the frame, and then marking additional points to relieve.



Once filing was complete, I sanded with 100 grit to blend the two. This was followed by 220, 320, and 400 grit sanding. And here's a quick tip – if you ever want to replicate Ruger's brushed stainless, start with 320 and then lightly scuff with 400.





Throughout this thread, I'll callout the time spent for each task. This should give you an idea of how long it takes for builders to complete these customs. In the case of the Bisley fitting, it took three hours.
 

Lee Martin

Hunter
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Dec 18, 2002
Messages
2,313
Location
Arlington, Virginia


Quick update on how I'm progressing. I spoke with Jack and the gripframe is on its way to Nevada. He'll reshape the Bisley and wrap it in high figure walnut. Then I had to dig up barrel. Searching the shop uncovered some from my .50 Alaskan BFR build. With Pac Nor backlogged six months, I'm glad I had a piece.

Stainless 0.510", 1:18 twist, unturned @ 1.10" o.d. I only need six-inches. We'll get another conversion out of this length.



Opening the frame requires a 3/16" carbide cutter. And it has to be a long endmill to clear the window. We'll perform this step over the weekend.



I also decided on a new .500 Linebaugh bullet; one I've wanted for some time. Using Mountain Molds software, I designed a 505 gr LFN on dual cavity blocks. I chose plain base because it'll top out around 1,200 fps. The specs if anyone is interested in ordering the same:





I believe it'll print better at 100 yards than the 525 WFN I've been shooting. I've spread the CoF and CoG more, lengthened the nose, upped the driving band height, and reduced the meplat. Casting a lighter 440 WFN from my LBT mold is another option for short range. But in multiple guns, it hasn't done well past 50 yards.
 

Lee Martin

Hunter
Joined
Dec 18, 2002
Messages
2,313
Location
Arlington, Virginia


I milled the frame window this afternoon using the 3/16" carbide cutter shown above. First I clamped the frame in a Bridgeport mounted vice. A spacer block was inserted into the hammer slot.



A quarter-inch rod is then placed in the basepin hole and indicated. It ran out less than a half-thousandth end-to-end. Ruger drilled the cylinder hole dead perpendicular to the front and rear edges. I also leveled the frame on both flats.



The endmill is zeroed on one edge and using digital readout I noted the reading for the opposite side. Next I moved the table over 0.010" and I feed out the cross feed. Ten-thousandths made a nice cut and put little-to-no strain on the bit. Three passes were made per side.



Here's a shot of our digital readout. You'll notice the X-axis is at 0.0304", which is the thirty-thou we removed. This was the final pass on the top edge.



Cutting the lower edge:





The roughed frame. I took a total of 0.060" top-to-bottom. Next time I'll flat file the surfaces and sand to a mirror finish. The corners also will be dressed for less radius. I could've use a smaller diameter endmill to do this, thus making tighter corners. But the smaller the endmill, the more it'll flex. Because the cylinder will be recessed and I'll use minimal barrel protrusion, the corner radiuses can't be too sweeping. However, some radius is recommended. Remember, a curved edge is stronger than a straight 90 degree. Ever wonder why airplane windows are oval and not square?



Total time for step 3 = 2 hours. BTW, I'm doing all the machining on this conversion. Dad says it's time to pass the torch completely. Little stress though, because he's always present.
 

Hondo44

Hawkeye
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Apr 3, 2009
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People's Republik of California
Lee Martin said:

Thx Lee,

Looking forward to your step-by-step build.

Might just be just the photo above, but seems like the main frame could come down just a bit where it meets the recoil shield for a more concentric curve with the top of the Bisley grip frame.

Not the case here, but that's one area especially needing attention when installing Bisleys on OMs.
 
Joined
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Kentucky
I love these threads, Lee. Hope my stupid questions aren't too big a bother.

You opened up the frame window 0.060" overall, 0.030" top and bottom. Before you cut, did you check to see that the opening was in fact "centered" on the base pin? I mean, one would assume so, but ya just never know. I suppose it wouldn't really matter if it were off a few thou so long as it clears your new cylinder, but I just wondered.

:)
 

contender

Ruger Guru
Joined
Sep 18, 2002
Messages
25,138
Location
Lake Lure NC USA
I've been following this build on Lee's site.
Folks,,, this is one heck of a project to follow. Lee is really putting his work out there.
 

Lee Martin

Hunter
Joined
Dec 18, 2002
Messages
2,313
Location
Arlington, Virginia


Small flat, round, and square files were used to dress the inner surfaces. I had to go slow throughout. The corners must be consistent and tight enough to clear the cylinder. When the entire window isn't consumed and the cylinder isn't fully recessed, it's not as critical. I relied on eyeball and hand to do this. Remove too much steel and you'll distort the edges. While that won't obstruct function, it wrecks the look of the gun.







On our conversions, I also polish the inside of the frame. This removes the cast texture and machine marks left from milling. The top, bottom, and breech face are worked with 220, 320, and finally 400 grit sandpaper. If mirror finish is your thing, lightly hit it with 800 grit.









Recap of hours spent so far:

Backstrap fitting = 3.0
Frame milling = 2.0
Frame window dressing = 2.0
Total = 7.0

This weekend I'll fit the oversized bolt to the frame.
 

Lee Martin

Hunter
Joined
Dec 18, 2002
Messages
2,313
Location
Arlington, Virginia


Prior to the cylinder build and re-timing, there are parts to amass. I won't do a conversion until I have the final components. Below you'll find:

1) Power Custom oversized bolt - I'll have to custom fit this
2) Power Custom heavier gate spring - again, minor fitting required
3) Belt Mountain #5 basepin
4) Bowen Classic Arms target rear sight - doesn't play into fit and tolerances, but I still want it ahead of time.

 

Lee Martin

Hunter
Joined
Dec 18, 2002
Messages
2,313
Location
Arlington, Virginia


Power Custom bolts ship wide at 0.100". As noted, the frame slot mics 0.096", the stock bolt is 0.092". That 0.004" worth of clearance is more tolerance than I like.

The new bolt has to be precision ground on a homemade jig. The jig is just a piece of steel with both sides surface ground dead even. Two holes are drilled to affix the bolt so it doesn't move while grinding. One hole holds the bolt peg, the other is for the cross pin.



The surface grinder I used is a Boyer-Schultz Six-Twelve Deluxe. These are high-end machines and hold to 0.0001".



The jig is positioned on a magnetic chuck and the bolt is ground until it just fits the frame.



Final width mics 0.0952", netting 0.0008" total clearance (0.0004" per side – very tight).

In the frame - it clears with no drag or side-play.



I also turned the cylinder from 2.0" round stock. This was done on our 15" Nordic lathe. Rough o.d. is 1.86". This weekend I'll cut it off, center drill, face, and final turn on a mandrel to 1.80".



 

Lee Martin

Hunter
Joined
Dec 18, 2002
Messages
2,313
Location
Arlington, Virginia


I came home yesterday to find a box from Jack Huntington. He completed the gripframe much faster than expected.





I'll spare you the obvious adjectives which describe his work. If you've ever considered his reshape, do it. He has done BFRs, XR3-REDs, and this Bisley for me. Nothing fits my hand better than his contouring and grips.

The 505 LFN mold also arrived from Mountain. From the time I placed the order to the time it hit my house was less than 2 weeks. You're hard pressed to find better service.





 
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