cylinder to barrel alignment

DeerSpy · Post by **DeerSpy** » Tue Feb 12, 2008 12:26 pm

Hi, ALL
I am going to make a tool to check the alignment of barrel to cylinder
and was wanting to know the tolerance that would be exceptable.
to shoot a good group.

Post by **Bullseye** » Tue Feb 12, 2008 5:30 pm

I'm really not a revolver guy, perhaps one of the others will chime in with a good tolerance answer for you.

R,
Bullseye

Blindpig · Post by **Blindpig** » Tue Feb 12, 2008 5:46 pm

Um, if I remember my revolver shooting days correctly, the cylinder-to-barrel alignment is not hyper-critical. The forcing cone assures that the bullet starts correctly in the barrel. If you have a revolver that's shaving lead, that's a horse of a different color.
Jump in here Toy, before I make a fool of myself. Isn't this one of your areas of expertise?

Post by **Bullseye** » Tue Feb 12, 2008 6:07 pm

The forcing cone to cylinder alignment is critical but the cylinder to barrel gap can be too. Typically that gap is between .006 to .008" but that can vary on some models. Spitting lead or excessive lead build-up in the forcing cone area are sure signs of cylinder misalignment. But the reason for misalignment can vary, could be due to a bent crane or maybe a worn cylinder bushing.

I know my revolvers but they are not my preferred specialty.

R,
Bullseye

toyfj40 · Post by **toyfj40** » Tue Feb 12, 2008 11:27 pm

Blindpig wrote:Um, if I remember my revolver shooting days correctly, the cylinder-to-barrel alignment is not hyper-critical. The forcing cone assures that the bullet starts correctly in the barrel. If you have a revolver that's shaving lead, that's a horse of a different color.
Jump in here Toy, before I make a fool of myself. Isn't this one of your areas of expertise?

I'm waayy too late!
My only 'expertise' is responding to gun-forum-questions...
not the "content", just a response...
(how did you know that one of my .38 'lite loads' was
inadequate pressure to get the bullet clear of the crown ??

I thought a gap more than 0.004-5" began to degrade the pressure.

tool? what's to align... well, beyond spinning the cylinder freely...
the bullet leaves the brass-mouth and is free-flying until it engages
the forcing cone... (or is my .38 experience not representative of .40-cal ? )

OK, bp, I spoke up and made a bigger fool of MYself than you did.
Do I win ?

bearandoldman · Post by **bearandoldman** » Wed Feb 13, 2008 10:12 am

You get the blue ribbon and the trophy Tex, you got my vote at least.

Blindpig · Post by **Blindpig** » Wed Feb 13, 2008 11:46 am

Well, Toy, it looks like we both should have just stayed in the weeds on this one and let Bullseye carry the ball (is that a mixed metaphor, or what?). Now you all know why I stick with auto-loaders; I don't really have enough sense to shoot a revolver!

DeerSpy · Post by **DeerSpy** » Wed Feb 13, 2008 12:20 pm

What I had was a problem wit shaving side of bullet off sent gun back to factory and all they did was make to forcing cone bigger not what I consider a good fix. Looks like me if you slam a bullet in to side of cone and deform it that could cause large group.
I’m getting about 8 inch groups with this gun and using same load in another gun
I get about 1.5 group.
I want to check difference alignment on both guns.

greener · Post by **greener** » Thu Feb 14, 2008 12:01 am

This link might be helpful
http://www.cactustactical.com/blog/2007 ... r-bag.html

Midway has a long list of gauges and reamers, as, probably does Brownells.

I checked one of my revolvers using this link
http://yarchive.net/gun/revolver/revolver_timing.html
if you alignment is off, you will see the cylinder walls.

How to fix it is beyond me if you have a problem.

Notes on the second link:
Make sure the revolver is unloaded.
It is mildly exciting if your wife happens to walk into the room just as you are looking down the barrel of a cocked revolver (see first note).
If you didn't clean the revolver after shooting lead bullets, it can be an ugly sight.

Blindpig · Post by **Blindpig** » Thu Feb 14, 2008 11:51 am

greener wrote:It is mildly exciting if your wife happens to walk into the room just as you are looking down the barrel of a cocked revolver.

I guess it'd be OK as long as long as she didn't scream " Go ahead and shoot!"

bearandoldman · Post by **bearandoldman** » Thu Feb 14, 2008 3:11 pm

Blindpig wrote:
greener wrote:It is mildly exciting if your wife happens to walk into the room just as you are looking down the barrel of a cocked revolver.
I guess it'd be OK as long as long as she didn't scream " Go ahead and shoot!"

Or, "Can I help you honey?"

greener · Post by **greener** » Thu Feb 14, 2008 8:02 pm

I believe it had something to do with the floor having just been cleaned.

bearandoldman · Post by **bearandoldman** » Thu Feb 14, 2008 8:09 pm

greener wrote:I believe it had something to do with the floor having just been cleaned.

No sense in messing up a nice clean floor.

greener · Post by **greener** » Thu Feb 14, 2008 10:41 pm

I learned very early not to cross SWMBO.

The check is one of those things you do after verifying the cylinders are empty three times.

greener · Post by **greener** » Thu Feb 14, 2008 10:45 pm

From the Iowegan Book of Knowledge-GP100
Cylinder-to-bore alignment: This requires using a Range Rod and a calibrated cartridge
case. Insert the Range Rod into the bore and push it in slowly until the tip of the Range
Rod moves through the cylinder and contacts the frame. You may have to help it a little
by wiggling the cylinder. Pull the Range Rod out until the tip is past the face of the
cylinder and observe the collar in reference to the muzzle. This will give an indication on
how deep the Range Rod has been inserted when testing. Turn the Range Rod handle so
the reference post is in the 12 o’clock position. Listen and feel for the feeler tip of the
Range Rod to contact the cylinder face as you move the Range Rod in and out. Repeat
the test with the reference post in the 3, 6, and 9 o’clock position. Ideally, the Range Rod
will enter the chamber throat without “ticking” on the cylinder face in all positions. If all
chambers pass this test, the gun is within specifications