GP100 Cylinder Alignment

[marb4]

I received my GP100 back from Ruger today for service. The pawl and cylinder latch were replaced. When inspecting the gun, I noticed what appears to be a slight misalignment of the cylinder chambers and the barrel. Is this amount of misalignment normal? Would appreciate any info you could offer. Thanks.

http://img294.imageshack.us/img294/7334/img4029a1vu0.jpg

NOTE: This pic is not my actual gun but one I found online. It looks exactly like what I'm seeing in mine on all six cylinders in full lockup.

I haven't had a chance to shoot it yet. Probably won't until next week. Thats the only way to know for sure if there's and issue.

One thing I did try. I made an inert dummy round out of and empty unprimed case with a bullet seated. (it was checked and checked again to ensure safety). Looking down the bore with a light I could see the round in the chamber. Even though there was the slight misalignment I could still see the entire lip of the case around the bullet. (look at a cartridge, bullet end on, and you'll see the brass case around the outside of the bullet circumference) This would suggest to me that even though the cylinder may not be perfectly aligned its still close enough that the bullet would enter the forcing cone without shaving. I did this for all six chambers.

I wonder what the tolerance for aligment is for the GP100? Any idea? I guess there must be some slight margin for error. When my cylinder locks it locks pretty tight. Very very slight movement.

Well I have an excuse to get to the range (if I needed one). That should be the true test.

 

[Pinecone]

marb4, Welcome to the forum! The only "right" way to check barrel/cylinder alignment is with the proper size "range rod". Understand that there will always be some very slight movement of the cylinder simply from built in parts tolerence necessary in revolvers to prevent "binding". I would assume that Ruger would have checked this alignment but we all know about "assumptions"! What did you send the revolver in for in the first place?.....................Dick :wink:

 

[marb4]

I originally sent it to Ruger because the end of the pawl appeared chipped. They replace the pawl, cylinder latch, and front cylinder latch. Did they check alignment? Who knows. Maybe they did and what I'm seeing is within specifications. I can rotate 4 of the 6 chambers into aligment when in full lock. 2 of them require a great deal of force to align. The only thing I can think of that would affect alignment would be the cylinder latch. Anything else you can think of? I wouldn't mind sending it back to Ruger if it wouldn't cost me another $75 to ship it back!

 

[EarlFH]

I would take it to a COMPETENT gunsmith, and have it checked. There's nothing worse than getting slivers of lead, or brass embedded in your face, and nose. I had a Model 29 that did that, and it's not fun.

EarlFH

 

[marb4]

Well I was able to sneak out of work at lunch and test out the revolver. Put 50 rounds downrange (158gr LRN). 32SA and 18DA. The gun is more accurate than I am still which it was before I sent it in for service. Didn't notice and spitting. No stings on the hands. A quick visual inspection didn't show any obvious leading in the forcing cone or bore. Will put it through a more complete range session next time I can get down there.

 

[Iron Mike Golf]

When you eyeballed the alignment, did you do that with the hammer cocked?

Is there enough play in the lock-up that you can turn the cylinder a tad and bring it into alignment? If so, you got no worries. There is supposed to be a tiny amount of rotation allowed in the cylinder to let the bullet align the chamber as the bullet enters the forcing cone.

 

[marb4]

Yes, the apparent misalignment was observed with the trigger held in the rearmost position which is where it would be at the discharge of the cartridge when the cylinder is in full lock. In 5 of the 6 chambers there is a little play where the misalignment pretty much completely disappears if you wiggle the cylinder. the 6th chamber has very little if any movement. If I tug real hard I can get this chamber to align.

Today at my limited range outing there didn't seem to be any real world issues. I'm going to continue to run the gun as it is and see how it goes.

Could a the new cylinder latch cause a slight misalignment? If so, is there an easy fix? (like installing a different latch)

 

[flatgate]

Yes, a new latch could cause misalignment. You've just discovered the reason for "line boring" a cylinder!

Ruger's usually have a wee bit of "slop" which, as you've noted, permits the cylinder to "self align" as the projectile makes the jump from cylinder throat to forcing cone.

Bottom line? How's it shoot when "bench rested" at an "easy to see and align with the sights" target?

Since "things have changed" on your revolver you will probably have to go through the exercise of finding the ammo it likes all over again.....

JMHO,

flatgate

 

[marb4]

I was able to sneak back out to the range last night after work and put another 100 rounds through the GP100. (158gr LRN) It seemed to be hitting point of aim pretty well. I didn't bench it but it was hitting as well off hand as it was before I sent it in and had the parts replaced. Still didn't notice any spitting or lead shavings/fouling when I cleaned it last night. Maybe there's enough give in the cylinder to allow it to self align or maybe the little bit of misalignment I observed is within specs. Anyway, it seemed to run fine. I'll keep shooting it and see what happens.