Revolver cylinder reaming

Bob Thompson · December 15, 2004, 01:32 PM

When I first got my Ruger Blackhawk Bisley .45 Colt its accuracy was only fair. After reading an article on this I found the front of the cylinders very tight for a cast bullet size of .452. All front of the chambers were running around .447-.448. I very carefully reamed with an adjustable reamer to get just a slight drag of a .452 bullet. Around .450-.451. Accuracy improvement was considerable with both cast and jacketed bullets. It seems as though the bullets were being swaged down too small to fit the barrel rifling tightly for good accuracy. Now the question: Has anybody else had these kind of results and can many other revolvers benefit from this procedure or was this a result of Rugers tolerances from the factory. Thanks much, Bob

Jim Watson · December 15, 2004, 02:07 PM

I have READ and HEARD of this many times. There are shops doing a regular business reaming Ruger cylinder throats out to bullet/groove diameter. Ruger is SAID to be holding their dimensions better now.

Colts and Smiths are liklier to run too large than too small from what I have HEARD and READ.

Ultima-Ratio · December 15, 2004, 02:19 PM

Hello, I like to use .431 on the S&W 629s, they can run as tight as .4275! Why .431? Cuz that's what the old 4 & 5 screws had and we know they shoot!

mikikanazawa · December 17, 2004, 02:53 PM

Reaming also gives you the opportunity to better line-up the cylinder bores with the barrel bore.

Harry Bonar · December 31, 2004, 10:39 AM

Dear Sir:
Rugers are great guns, but their quality control has always been a problem. If your groove dia. on that ruger is, say .429 then the exit on the cylinders should be at least (if not exactly) .429.
I was recently given a super redhawk in .454 casull. When cocking single action on one cylinder the locking bolt would hang up rotation. Since I had plenty of verticle lock bolt travel I maintained the angle andradius and dressed it down about .005 - .007. Solved the problem. Timimg is better now and locking bolt still has plenty of travel; I could have gone inside and made adjustments to the rod that controls that (DA was aok) but decided to fix it this way - you must watch your timing!
The cyl. gap on the Blackhawks used to be .005 on one side and .015 on the other. Wrote Ruger and Bill sent me a personal letter which I now treasure. Then, on the Blackhawks, the bbl. would be aligned to the left of the top strap of the frame. They corrected that. There is a simple way to correct cyl rotational looseness also. Rugers can be fixed! Your .45 can benefit from the above. Harry

Bob Thompson · December 31, 2004, 11:45 AM

Thanks Harry, I will be checking those things straight a way. There doesn't seem to be any hangup or dragging of the lockup pin but I will check. At least no marks on the cylinder. What do you think of the aftermarket cylinder pin offered evidently to have a bit tighter fit. And it would seem hard to correct cylinder gap, is it? Bob T.

December 15, 2004, 01:32 PM	#1
Bob Thompson Senior Member Join Date: December 28, 1998 Location: riverdale,ut,usa Posts: 136	Revolver cylinder reaming When I first got my Ruger Blackhawk Bisley .45 Colt its accuracy was only fair. After reading an article on this I found the front of the cylinders very tight for a cast bullet size of .452. All front of the chambers were running around .447-.448. I very carefully reamed with an adjustable reamer to get just a slight drag of a .452 bullet. Around .450-.451. Accuracy improvement was considerable with both cast and jacketed bullets. It seems as though the bullets were being swaged down too small to fit the barrel rifling tightly for good accuracy. Now the question: Has anybody else had these kind of results and can many other revolvers benefit from this procedure or was this a result of Rugers tolerances from the factory. Thanks much, Bob

December 15, 2004, 02:19 PM	#3
Ultima-Ratio Junior member Join Date: May 18, 2004 Location: Anchorage Alaska Posts: 227	Throat Reaming? Hello, I like to use .431 on the S&W 629s, they can run as tight as .4275! Why .431? Cuz that's what the old 4 & 5 screws had and we know they shoot!

December 31, 2004, 10:39 AM	#5
Harry Bonar Senior Member Join Date: December 5, 2004 Location: In the Vincent, Ohio general area. Posts: 1,804	re-ruger cyl. Dear Sir: Rugers are great guns, but their quality control has always been a problem. If your groove dia. on that ruger is, say .429 then the exit on the cylinders should be at least (if not exactly) .429. I was recently given a super redhawk in .454 casull. When cocking single action on one cylinder the locking bolt would hang up rotation. Since I had plenty of verticle lock bolt travel I maintained the angle andradius and dressed it down about .005 - .007. Solved the problem. Timimg is better now and locking bolt still has plenty of travel; I could have gone inside and made adjustments to the rod that controls that (DA was aok) but decided to fix it this way - you must watch your timing! The cyl. gap on the Blackhawks used to be .005 on one side and .015 on the other. Wrote Ruger and Bill sent me a personal letter which I now treasure. Then, on the Blackhawks, the bbl. would be aligned to the left of the top strap of the frame. They corrected that. There is a simple way to correct cyl rotational looseness also. Rugers can be fixed! Your .45 can benefit from the above. Harry

December 15, 2004, 02:07 PM	#2
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,535	I have READ and HEARD of this many times. There are shops doing a regular business reaming Ruger cylinder throats out to bullet/groove diameter. Ruger is SAID to be holding their dimensions better now. Colts and Smiths are liklier to run too large than too small from what I have HEARD and READ.

December 17, 2004, 02:53 PM	#4
mikikanazawa Senior Member Join Date: September 26, 2004 Posts: 449	Reaming also gives you the opportunity to better line-up the cylinder bores with the barrel bore.

December 31, 2004, 11:45 AM	#6
Bob Thompson Senior Member Join Date: December 28, 1998 Location: riverdale,ut,usa Posts: 136	Thanks Harry, I will be checking those things straight a way. There doesn't seem to be any hangup or dragging of the lockup pin but I will check. At least no marks on the cylinder. What do you think of the aftermarket cylinder pin offered evidently to have a bit tighter fit. And it would seem hard to correct cylinder gap, is it? Bob T.