revolver cylinder to barrel gap

electric-amish · 05-19-2009, 07:20 AM

A smith and wesson 642-2 i just got is a flame thrower.

The gap on the cylinder to barrel is about 7.5/1000s useing a feeler guage. I would like it to be about 5/1000 to slow down the light show of the flash.

Would an end shake bushing of 2/1000 move the cylinder forward to correct this?

Thanks

Electric-Amish

dfariswheel · 05-19-2009, 05:50 PM

The ONLY time you ever use washers in the S&W is if you have a cylinder end shake problem.

That is, if you can move the cylinder back and forth in the frame more than about 0.005" or more you have excessive end shake.
Installing a washer to try to fix barrel/cylinder gap is exactly the WRONG thing to do.
Trying to move the cylinder forward will give excess head space if you could even do it and not have the cylinder so tight it won't rotate in the frame.

In revolvers, if you have excess barrel/cylinder gap, ALL you can do is have the barrel set back one thread or replace the barrel.
In S&W revolvers this may not be possible due to issues with the length of the ejector rod and the front lock up.

Your choices are:
Live with it.
Send the gun to S&W or another QUALIFIED S&W gunsmith to either have the barrel set back (if possible) or to have a new barrel fitted to the frame.
Hint: This is NO JOB for most local gunsmiths. Most of them don't even have the right tools, much less know how to do the job right.

My advice: You have a working gun that's well within factory specifications. A barrel/cylinder gap is about perfect at 0.005" to 0.006", and is not excessive at 0.007' like you have. Closing the gap a few thousands won't help much with flash.
For that, pick ammunition loaded with lower flash powders.
In short, fix the ammo not the gun. The gun isn't defective.

electric-amish · 05-19-2009, 10:41 PM

Thanks good info.

I'll look for lower flash powders.

E-A

Dave W. Waits · 11-25-2009, 01:27 PM

FWIW, S&W does a barrel setback and sets Cylinder-Gap for $75.00. Since I no longer have the correct jigs I'm having them do it to a 28-2 I have with a .009 Cylinder-Gap.

dfariswheel · 11-27-2009, 07:11 PM

S&W has let their specs slide to the point that guns are being listed as "in spec" with gaps of as much as .012".
This is not too popular with older owners who remember .005" gaps from the factory.

05-19-2009, 07:20 AM	#1
electric-amish Join Date: May 2009 Posts: 3	cylinder barrel gap---need help A smith and wesson 642-2 i just got is a flame thrower. The gap on the cylinder to barrel is about 7.5/1000s useing a feeler guage. I would like it to be about 5/1000 to slow down the light show of the flash. Would an end shake bushing of 2/1000 move the cylinder forward to correct this? Thanks Electric-Amish

05-19-2009, 05:50 PM	#2
dfariswheel Senior Member Join Date: Jun 2001 Posts: 1,800	Re: cylinder barrel gap---need help The ONLY time you ever use washers in the S&W is if you have a cylinder end shake problem. That is, if you can move the cylinder back and forth in the frame more than about 0.005" or more you have excessive end shake. Installing a washer to try to fix barrel/cylinder gap is exactly the WRONG thing to do. Trying to move the cylinder forward will give excess head space if you could even do it and not have the cylinder so tight it won't rotate in the frame. In revolvers, if you have excess barrel/cylinder gap, ALL you can do is have the barrel set back one thread or replace the barrel. In S&W revolvers this may not be possible due to issues with the length of the ejector rod and the front lock up. Your choices are: Live with it. Send the gun to S&W or another QUALIFIED S&W gunsmith to either have the barrel set back (if possible) or to have a new barrel fitted to the frame. Hint: This is NO JOB for most local gunsmiths. Most of them don't even have the right tools, much less know how to do the job right. My advice: You have a working gun that's well within factory specifications. A barrel/cylinder gap is about perfect at 0.005" to 0.006", and is not excessive at 0.007' like you have. Closing the gap a few thousands won't help much with flash. For that, pick ammunition loaded with lower flash powders. In short, fix the ammo not the gun. The gun isn't defective.

05-19-2009, 10:41 PM	#3
electric-amish Join Date: May 2009 Posts: 3	Re: cylinder barrel gap---need help Thanks good info. I'll look for lower flash powders. E-A

11-25-2009, 01:27 PM	#4
Dave W. Waits Junior Member Join Date: Aug 2009 Posts: 24	Re: cylinder barrel gap---need help FWIW, S&W does a barrel setback and sets Cylinder-Gap for $75.00. Since I no longer have the correct jigs I'm having them do it to a 28-2 I have with a .009 Cylinder-Gap.

11-27-2009, 07:11 PM	#5
dfariswheel Senior Member Join Date: Jun 2001 Posts: 1,800	Re: cylinder barrel gap---need help S&W has let their specs slide to the point that guns are being listed as "in spec" with gaps of as much as .012". This is not too popular with older owners who remember .005" gaps from the factory.

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