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by Gordon Marts

It's a project I've been plotting for quite some time, and an unexpected bailout by a client left me with a couple of free days in the shop to work on it. 

Starting material was a Colt's Bisley Model revolver circa 1902, in my favorite chambering: 38WCF. The gun was a no-finish gun with a damaged (read “FITZ” job) trigger guard, and a worn down cylinder bushing which caused a lot of end play in the cylinder but was easily remedied. I bought it for a fair price, figuring to rebuild it as a shooter, or part it out and use the frame to rebuild a 38-40 Bisley that blew up in my hands a couple of years ago and had lost it's topstrap and cylinder. 

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Initially all I did was to tighten up the cylinder play, and fit a new hand to correct a timing issue. I replaced the trigger guard with another Bisley TG from the parts box and was off to the races. The gun shot pretty well but printed a bit high, so I welded up the top of the front sight blade to make it taller and dressed it down to the proper height a few rounds and a few file strokes at a time. It then shot point of aim with my standard load. It seemed that this gun might be the basic platform to build my #5 SAA. Since it already had quite a few parts that were not part of this gun when it left the factory, and had basically no original finish remaining, it’s collector value was not great and it seemed like a good candidate for a remodel of this type. 

What an education. 

Having seen photos of Elmer's original #5 as designed by Croft and built by Sedgley, I knew that it had been built using a SAA triggerguard and a modified Bisley backstrap. I had a grip tracing provided to me by a kindly angel and a reasonably well stocked Colt’s parts box. Here we go....  

My initial concept of the project was that this was basically a grip modification and swap. It turns out that there is a bit more involved in this conversion.

What an eye-opener. 

Stage one was the grip modifications. This was basically a cut and bend on the backstrap, and the fabrication of a new bottom strap. This was all accomplished with a hacksaw, file, drill press, and a belt grinder. I adjusted the shape of the backstrap slightly from the original design to give me the best sight alignment with MY grip. If I close my eyes and point the gun, when I open them the sights are in perfect vertical alignment. This may be the true beauty of a custom gripframe. It also speaks wonderfully for the basic Keith-Croft design. 

The metal mods to the grip took about three hours using hand tools a wire feed welder and a belt grinder. These turned out to be the easy part. I knew going in what the basic parts were to do the conversion, but only when I began to assemble the gun did I realize that there were quite a few other problems involved. 

First of all was the problem of the mainspring to power this puppy. The Colt Bisley hammer that is employed in this conversion is a true marvel of design. I find it to be the easiest cocking and best looking hammer ever created for a single action sixgun. It is actuated by a curved mainspring which has specialized fingers that mate to a pivoting stirrup which dangles from the bottom of the Bisley hammer. The normal Bisley triggerguard/frontstrap positions and holds this mainspring in a very specific orientation to the hammer stirrup in order to provide proper tension of the mainspring against the hammer. 

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SAA, #5, and Bisley Model spring geometry

The rub is that the SAA frontstrap employed in the #5 is designed to hold an entirely different mainspring in an entirely different position. Clearly a little re-engineering was going to be necessary. Basically this was achieved by mocking up the necessary alignment, and then making a seat of the pants guess about how much mainspring tension should be present with the hammer at rest. I fabricated an angled block and keeper from steel bar stock to position the base end of the mainspring in the position I thought it needed to have. It took a couple of tries to get it right. It also became apparent that the Bisley mainspring in it’s original form was too long to work in conjunction with the shorter SAA triggerguard/frontstrap. A shortening was in order along with boring a new hole for the Mainspring attachment screw. I would have given my right arm to be able to spend an hour with Croft and Sedgley at this point and ask them how they did it, but this alas was not possible. Neither did I have an opportunity to look under the grips of Elmer's gun. The short story is that these mainsprings are HARD. Grinding off about a half inch wasn’t too tough (these things will EAT a hacksaw blade) but I destroyed several good HSS drill bits in producing the .200” hole I needed for the screw, but eventually I got it. The other option would have been to soften the spring, modify it and then re-temper. I felt that given my modest abilities and equipment, this would be asking too much. If I didn’t get it perfect, I got it close enough work well. 

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Modified Bisley mainspring and tensioning blocks

At this point, I thought I had the conversion pretty well knocked out. More was to be revealed. Just as the Bisley hammer is designed to work with a Bisley mainspring, it is also designed to function with a Bisley trigger. The smaller SAA triggerguard used in this project however will not admit a Bisley trigger without major modifications to both the triggerguard and the trigger. In looking at the pictures of Elmer's gun it appears they used a SAA trigger, and so that is the approach I decided to use. The parts went together O.K. and with the backstrap and bolt removed the revolver functioned with the new mainspring and trigger. However when the new backstrap was attached, and the bolt and bolt spring installed, more problems became obvious. Most apparent was the fact that the hammer would not retract far enough to go into full cock. The cylinder was rotating fully and the bolt was locking properly in the cylinder recess, but the cylinder lockup was occurring before the sear tip of the trigger nose could engage the hammers full-cock notch. We had a serious timing problem. 

Disassembly of the gun and comparison of the SAA trigger to the original Bisley trigger told the tale. As much as I have tried to become well versed in Colt’s minutiae, I did not realize that the Bisley trigger has a significantly longer nose than does the SAA trigger. The Bisley trigger nose length was .275” vs. .330” for the SAA. I realized some trigger modifications would be necessary as well. Using the Bisley trigger as a guide, I slowly removed material from the nose of the trigger until the nose would engage to the full-cock notch a few thousandths of an inch before the cylinder bolt completely stops the cylinders rotation. This is the absolute max. sear length, and leaves a little metal left for final sear angle and length adjustment in the final trigger job that will follow. A quick case hardening of the nose with Casenit to preserve it’s shape and the lockwork was up and running. 

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SAA and Bisley triggers and Mainsprings

Anyway we now have a functioning sixgun. It points, locks, and drops. It was a good shooter before the mod’s, and I have every expectation that it will continue to be .I have completed a set of grips for it and now that they are finished I will take it out for a preliminary test drive. 

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I will probably do some other upgrades in the fullness of time including S&W revolver sights and perhaps a quality case and blue restoration, engraving, who knows? But first I’m gonna shoot it. 

Write to Gordon