SP101 Cylinder binding

[Petrol & Powder]

I've got a "new to me" Ruger SP101 and I'm having some problems with the cylinder dragging on the yoke when using cast bullets. At first I thought I had a barrel/cylinder gap or headspace problem but I've ruled those out. The B/C gap is on the tight side at .006" but it works just fine with jacketed bullets. The headspace is also OK and none of my casings are dragging on the breach face or recoil shield. After just a few rounds the resistance quickly builds to the point that double action operation (all that is available on this particular revolver) is almost impossible.
After just a few rounds, the cylinder is difficult to rotate even when the action is open and the cylinder is OUT of the frame. If I open the cylinder and rotate the cylinder by hand I can feel it binding and with some work I can get it free up a little. It seems to be accumulating lead/powder/lube/whatever.... right at the junction between the front of the cylinder and the yoke. If I disassemble the gun and remove the cylinder from the crane, wipe down the section of the yoke that the cylinder rotates on and reassemble; it works fine again.

I noticed that the Ruger does not incorporate a gas ring like the S&W cylinder/yoke. Is the SP101 just not a cast bullet friendly design? It dry fires fine when clean and works as it should with jacketed bullets. I've owned SP101's in the past that weren't this tight.

[Ickisrulz]

This is my experience also. After about 100-150 rounds I have to take the cylinder off and clean the crane. I've used several powders, three types of lube and two bullet designs. Doesn't help!

http://castboolits.gunloads.com/showthread.php?203911-SP-101-intensive-cleaning-required

[JLarsson]

I wouldn't call .006" B/C gap particularly "tight". Nothing wrong with it, and on a production gun, it's about as good as you'll get - or want.

As far as the cylinder rotating roughly or with difficulty, are you getting a lot of unburned powder, powder residue, or lead splatter back from the forcing cone area? Might have to switch powders if the former two, and have the timing checked if it's the latter.

[Petrol & Powder]

I'm not getting a lot of lead splatter or unburned powder. If fact, the same loads work well in GP100's and my S&W's. Seems to be confined to the SP101. I'm using ww231 and the timing is OK.

[Petrol & Powder]

OK Nise, we'll keep this thread "clean". :wink:

I'm using White Label BAC lube.

[Petrol & Powder]

This is my experience also. After about 100-150 rounds I have to take the cylinder off and clean the crane. I've used several powders, three types of lube and two bullet designs. Doesn't help!

http://castboolits.gunloads.com/showthread.php?203911-SP-101-intensive-cleaning-required

10-4, read the older thread and I concur.

[JLarsson]

I'm not getting a lot of lead splatter or unburned powder. If fact, the same loads work well in GP100's and my S&W's. Seems to be confined to the SP101. I'm using ww231 and the timing is OK.

Beats me. Should be good-to-go. I've been shooting some "dirty" loads in my 2.25" barrel SP101. H110 and 158 gr. JHP's (I know, this is the BOOLIT site - it's what I got). The gun is filthy but no drag, hesitation, etc.

[Petrol & Powder]

Yea, I hate to say it, but it works fine with J-word bullets !

[monge]

Check your base pin polish and lube it STP works great , worked for me

[Outpost75]

I assume that your SP101 is a .357, not a .38 Special. Mine is an early gun in .38 Special and had never had any cylinder binding problems with bullets cast of COWW, air cooled only, lubricated witb Lee Liquid Alox and fired with full charges of Bullseye powder. It has fired thousands of rounds of cast bullet reloads as a training gun for CCW classes.

When I clean I use Ed's Red and also apply two drops Castrol synthetic ATF in the crane arbor with an eye dropper. I've never had to disassemble the cylinder from the crane assembly.

[JLarsson]

Yea, I hate to say it, but it works fine with J-word bullets !

I guess I am officially a member of this site now. I have seen "J-word" numerous times in various posts (mostly for sale), but never figured out what it meant until now. I thought it was like a brand name for somebody's special cast boolits.

Feel free to heap abuse on me at this point...

[Three-Fifty-Seven]

,,,,,,

[wlc]

No problems with mine either. Has had nothing but cast shot through it. I typically load it with 231 and the lube varies from tumble lube to speed green to some hard lube on boolits from a local commercial casting outfit. Usually clean after each outing with it. We usually shoot 1-200 rounds at a time.

[Petrol & Powder]

Outpost75 - yep it's one of the .357 models. I had one of the older ones that had the shorter .357 cylinder and sold it back when nobody knew they would be the rare ones. I think it was a better gun. I just got done cleaning it really well. Everything checks out OK, but there was a lot of lead in the throats & forcing cone.
I think my alloy might actually have been too soft (I know, generally it's the other way around). My last batch was pure lead with magnum shot added for antimony. I think maybe I got it a little too soft, not sure.
In any event, My GP's and S&W have a gas ring at the front of the cylinder and I think that's a better design. Why Ruger omitted that on the SP is a mystery to me.

[Outpost75]

The gas ring is not needed with jacketed bullets, and in. 357 they presume those are what people will shoot.

Try the Castrol ATF in the crane arbor.

[Petrol & Powder]

10-4 on the ATF. Thanks

[Petrol & Powder]

OK, this is really starting to give me an ulcer. Cleaned the gun till it was spotless inside and out. Lubed the crane with a little synthetic trans fluid and reassembled. All was good. I could just start a .006" feeler gage in the B/C gap with the cylinder held to the rear. A .005" gage would pass all the way through the gap but was snug.
It shot fine with jacketed factory ammo. Then I switched to cast loads with different sized 158 gr. bullets, all loaded over 4.4 grs. of ww231. It did a little better and the cylinder didn't bind on the yoke but it started binding between the front face of the cylinder and the forcing cone. The face of the cylinder actually showed signs of dragging across the forcing cone with the fouling being pulled across the face of the cylinder in the direction of rotation.
So the cylinder is no longer binding on the arbor. (the cylinder spins freely when open, even when dirty) But the B/C gap seems to be too tight and maybe even a little tighter near the top strap than at the bottom of the forcing cone.
If I had a 90 degree cutter and some pilots, I would dress the rear face of the forcing cone.