Stumped on S&W M&P cylinder drag

Sir William · November 6, 2004, 11:12 PM

OK. serial # 7570XX This is a WWII British Service revolver. This is NOT a V or victory model. It is a 38 S&W caliber. I am experiencing "drag" on three chambers. SA/DA doesn't matter. I don't have cylinder drag or rubbing on the bolt. I don't have any cylinder binding or arbor friction. What I may have narrowed it down to is a ejector rod problem. Is there a possibility that there is binding/friction from the ejector? Spring binding? The revolver when dryfired, drags on three sequential chambers then "feels" free. This revolver shows 0 bare metal anywhere that would indicate rubbing, binding or friction. I am thinking there must be something in the ejector rod. If you rotate the cylinder with the cylinder swung out, there is a point of resistence from the ejector. The ejector seems to bind and does not retract from spring pressure. If the cylinder is rotated, the ejector snaps back. Any thoughts? Timing/lock-up are fine.

mtnboomer · November 7, 2004, 02:55 AM

Have a gunsmith check the crane as it could be warped slightly (possibly from someone repeatedly slapping it closed before you got it). With the cylinder crane closed, look at the front of the frame below the barrel. There should only be a hairline gap between the crane and frame at any point. If it shows a widening at any point, the crane is warped. If not severe, it can be straightened.

Sir William · November 7, 2004, 04:45 AM

Thanks. I checked that. I still suspect the ejector. I disassembled the cylnder assemly again. I believe there is a tolerance problem inside the ejector tunnel. I think I will try to find another ejector tube. Any other ideas?

PzB41 · November 7, 2004, 02:10 PM

Hi William,

I had a Chief's Special with a similar problem. The way I further narrowed down the problem is:

After measuring the cylinder gags, disassemble the entire crane/yoke/cylinder. Any parts that are cylindrical, including the locking rod, roll on a table or other flat surface. If they are out of true, it will be immediately apparent. The problem with mine was not the locking rod itself, but the ejector rod. Soemtimes, previous owners could have been a bit overzealous when it comes to disassembly/assembly. If it is out of true, it could very will bind the revolver on two or three chambers. Usually, a replacement can be had for cheap money and replacing it will solve the problem.

If the problem appears to be the crane itself, the way to properly find out what's going on (as opposed to eyeballing it. I challenge anyone to tell the difference between a gap .007" from one .009" by just eyeballing it) is to use feeler gauges and measure on every chamber, then compare the measurements with the factory specs.

Try to avoid replacing the crane itself, if you can get away with it. The cylinder gap is critical, and to get the gap spaced correctly you'll likely need thrust washers to take up the slack.

When/if you decide on replacing the ejector rod or locking rod (most likely the causation of the problem, from what you have told us so far), if you go with used parts (say, from Numrich GPC or Jack First), try to get them on the phone and specify either NEW (or New/Old stock) or the best used stuff they have. Replacing bent parts with "new" bent parts is just silly. GPC used to have a good crew of guys working the stockroom, and knew just what you were talking about when you asked for something, but now employ college kids or high school kids to gopher for the parts. Most times, they couldn't tell the difference between a good honest clean used part and a piece of junk. I'd say a good 30% of the parts I order from GPC have to go back just because they are in such poor condition or are incorrect. If I had to buy a part, I'd go with Jack First. Call them and talk to them, and they'll hook you up.

Pz

If you go with replacing parts instead of repairing them, you should replace all the springs involved as well. Older revolver like that might benefit from a simple spring swap. Besides, you're going to have it apart anyways.

Sir William · November 7, 2004, 10:43 PM

I like THAT answer! I did something unusual. I lit the ejector housing up from the star end w/o the ejector rod in place with the cylinder assembled. Guess what? The tunnel looks like a golf course on one side! I will have to replace the ejector plunger/ejector housing. Oh, joy.

November 6, 2004, 11:12 PM	#1
Sir William Senior Member Join Date: October 13, 2004 Posts: 3,261	Stumped on S&W M&P cylinder drag OK. serial # 7570XX This is a WWII British Service revolver. This is NOT a V or victory model. It is a 38 S&W caliber. I am experiencing "drag" on three chambers. SA/DA doesn't matter. I don't have cylinder drag or rubbing on the bolt. I don't have any cylinder binding or arbor friction. What I may have narrowed it down to is a ejector rod problem. Is there a possibility that there is binding/friction from the ejector? Spring binding? The revolver when dryfired, drags on three sequential chambers then "feels" free. This revolver shows 0 bare metal anywhere that would indicate rubbing, binding or friction. I am thinking there must be something in the ejector rod. If you rotate the cylinder with the cylinder swung out, there is a point of resistence from the ejector. The ejector seems to bind and does not retract from spring pressure. If the cylinder is rotated, the ejector snaps back. Any thoughts? Timing/lock-up are fine.

November 7, 2004, 02:55 AM	#2
mtnboomer Senior Member Join Date: July 9, 2004 Location: Oklahoma by birth. America by the grace of God. Posts: 635	Have a gunsmith check the crane as it could be warped slightly (possibly from someone repeatedly slapping it closed before you got it). With the cylinder crane closed, look at the front of the frame below the barrel. There should only be a hairline gap between the crane and frame at any point. If it shows a widening at any point, the crane is warped. If not severe, it can be straightened. __________________ Quando Omni Flunkus Moritati (If all else fails - play dead!) Support the Second Amendment. Join the NRA > http://www.nra.org < Oklahoma State & Big 12 - #1 GO POKES!!!!!

November 7, 2004, 02:10 PM	#4
PzB41 Member Join Date: October 27, 2004 Location: South of the Mason/Dixon Line in horse country. Posts: 23	Hi William, I had a Chief's Special with a similar problem. The way I further narrowed down the problem is: After measuring the cylinder gags, disassemble the entire crane/yoke/cylinder. Any parts that are cylindrical, including the locking rod, roll on a table or other flat surface. If they are out of true, it will be immediately apparent. The problem with mine was not the locking rod itself, but the ejector rod. Soemtimes, previous owners could have been a bit overzealous when it comes to disassembly/assembly. If it is out of true, it could very will bind the revolver on two or three chambers. Usually, a replacement can be had for cheap money and replacing it will solve the problem. If the problem appears to be the crane itself, the way to properly find out what's going on (as opposed to eyeballing it. I challenge anyone to tell the difference between a gap .007" from one .009" by just eyeballing it) is to use feeler gauges and measure on every chamber, then compare the measurements with the factory specs. Try to avoid replacing the crane itself, if you can get away with it. The cylinder gap is critical, and to get the gap spaced correctly you'll likely need thrust washers to take up the slack. When/if you decide on replacing the ejector rod or locking rod (most likely the causation of the problem, from what you have told us so far), if you go with used parts (say, from Numrich GPC or Jack First), try to get them on the phone and specify either NEW (or New/Old stock) or the best used stuff they have. Replacing bent parts with "new" bent parts is just silly. GPC used to have a good crew of guys working the stockroom, and knew just what you were talking about when you asked for something, but now employ college kids or high school kids to gopher for the parts. Most times, they couldn't tell the difference between a good honest clean used part and a piece of junk. I'd say a good 30% of the parts I order from GPC have to go back just because they are in such poor condition or are incorrect. If I had to buy a part, I'd go with Jack First. Call them and talk to them, and they'll hook you up. Pz If you go with replacing parts instead of repairing them, you should replace all the springs involved as well. Older revolver like that might benefit from a simple spring swap. Besides, you're going to have it apart anyways. __________________ "I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man" -- Thomas Jefferson Current favorites in the safe: Pre-64 M70 in .300 WinMag, Steyr SSG69, H&K 93A4 and 91, M21, H&K USP (C), Colt 1911A1 & Anaconda, S&W M57. Disabled Veteran (10 Years Active, US Army) NRA Life Member Graduate CST, Denver, CO. Precision Rifle Instructor Professional Gunsmith/Riflemaker Student of Engineering

November 7, 2004, 04:45 AM	#3
Sir William Senior Member Join Date: October 13, 2004 Posts: 3,261	Thanks. I checked that. I still suspect the ejector. I disassembled the cylnder assemly again. I believe there is a tolerance problem inside the ejector tunnel. I think I will try to find another ejector tube. Any other ideas?

November 7, 2004, 10:43 PM	#5
Sir William Senior Member Join Date: October 13, 2004 Posts: 3,261	I like THAT answer! I did something unusual. I lit the ejector housing up from the star end w/o the ejector rod in place with the cylinder assembled. Guess what? The tunnel looks like a golf course on one side! I will have to replace the ejector plunger/ejector housing. Oh, joy.