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Discussion Starter · #1 ·
just bought a new GP100. got maybe 1mm (or slightly less) gap between cylinder and breech. also a little play in cylinder rotation. doesn't seem to lock up as tightly as some other revolvers i've tried. i'm new and not very knowledgeable. is this a big deal, or should i just see how it shoots?
 

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1MM is about .040 that's a lot, and most likely not correct.

Try measuring with a feeler gauge. I think Ruger's max tolerance is close to .012 max.
A little big IMHO .004 to .006 is nice.
A little larger gap just sacrifices a a small amount of F P S to much can create an objectionable amount of gas and powder blast between the Cylinder face and the back of the barrel.

The cylinder needs a tad of play at lock up to allow the bullet to be pulled into alignment.

Naturally all these aspects have +- tolerances.

Ruger would fix anything out of spec, thing is it's hard to say with your description.

Some manufacturers hold to tighter Specs than some others.
 

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just bought a new GP100. got maybe 1mm (or slightly less) gap between cylinder and breech. also a little play in cylinder rotation. doesn't seem to lock up as tightly as some other revolvers i've tried. i'm new and not very knowledgeable. is this a big deal, or should i just see how it shoots?
It's pretty standard for revolvers to have a cylinder-barrel gap of 0.006", with some revolvers going as high (in my limited experience) at 0.012". A millimeter would be 0.04", which - as noted above - is a bit wide.



Jim
 

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Discussion Starter · #4 ·
thanks for the info, gents. i just got a brief look at it today and am now in the 3 day wait period. i will take a feeler gauge with me when i go to pick it up.
 

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Discussion Starter · #6 ·
foytfoyt, i think i mean between the face of the cylinder and the breech end of the barrel. i am sure that my estimate is way off on the real measurement. i will try to get an accurate measurement when i pick it up. if it is over 0.012" i'll give Ruger a call. i appreciate the reassurance about the lock up feel.
 

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I take it from your comments you are somewhat inexperienced with revolvers and maybe firearms in general. You may need some hands on help from a trustworthy experienced shooter. Inspect the gun before taking delivery but don't get to far ahead of yourself and start worrying about cylinder gap before you even have it in hand or have shot the gun.

The internet is a good thing but reading here and other places one easily gets the impression that the first thing a buyer needs to do is start switching springs, polishing, sending back to Ruger etc. etc. Nothing could be farther from reality. Most shooters are served very well just as they come from the factory.
 

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As far as lock-up is concerned, it is measured (or contemplated) only when an unloaded gun is dry-fired (or the equivalent of allowing the hammer to fall slowly by one's hand) and the trigger NOT RELEASED while the hammer is down. One should be able to see the firing pin protruding in this condition. At this point the lock-up is FAR tighter than simply twiddling the cylinder with no finger on the trigger.
 

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As far as lock-up is concerned, it is measured (or contemplated) only when an unloaded gun is dry-fired (or the equivalent of allowing the hammer to fall slowly by one's hand) and the trigger NOT RELEASED while the hammer is down. One should be able to see the firing pin protruding in this condition. At this point the lock-up is FAR tighter than simply twiddling the cylinder with no finger on the trigger.
I believe that was/is true with Colt revolvers because of a different internal system as to how it locks up. I have never seen this on a Ruger revolver, I have three.
 

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The "acceptable specs" of a new revolver have been relaxed, it seems, by both S&W and Ruger.

Extensive reading has shown reports of both new S&W and Ruger DA revolvers with b/c gaps ranging from .003" to .015" and although neither manufacturer likes to share what they use as a "cutoff" range for b/c gap but it seems to be .012".

It used to be .006" was the "sweet spot" but now they are coming out looser.

It depends on what you plan to use the gun for, in fact, you don't want TOO tight, I found this out........had a brand new GP100 with too little b/c gap, it locked up. I had to send it back to Ruger, it came back with .008" and shoots like a laser.

I would rather have more b/c gap and less endshake, however for a defensive or "combat" revolver a little "slop" can be OK, it will help the revolver function if some unburned powder gets wedged in somewhere or you drop the gun in the mud, etc.
 

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I believe that was/is true with Colt revolvers because of a different internal system as to how it locks up. I have never seen this on a Ruger revolver, I have three.
I also have three, all DA's, and they are all alike, and all have several thousand rounds through each, and had that same characteristic since new. Also, so does every Ruger revolver (DA) that I handle at gun shops. Perhaps SA's are different?
 

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The lockup should be tighter when holding the trigger all the way back then when the trigger is forward and the hammer down as the pawl/ratchet/hand when the trigger is held back has slid up the ratchet tooth and is on the side holding it to minimize cylinder play. This is as on a S&W. The old style Colts had ratchets with 2 teeth with one for cylinder rotation and the second to push on the ratchet at lockup against the cylinder bolt to firmly hold the cylinder. A little play is desirable in Rugers to allow the bullet to exit the cylinder into and align in the forcing cone.
 

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The lock up in a Ruger is not the same as a colt, At least the older ones.

Back when, My duty gun was a Colt Trooper, off duty was an S&W 5 shot chief, The lock work was totally different. You could drop the hammer and hold the trigger back with vise grips on the smith and if you had side to side play in the cylinder it did not go away.

The colt lock up was great as long as it was correct, it left very, very little room for any Mis-alinement of any of the lock up depended parts, UN-like the smith.

The Ruger does not hold the cylinder locked up tight, don't care how you hold the trigger, ain't built that way. If you have a Ruger with very excessive side to side play in the Cylinder, holding the trigger back may reduce it some do to the interaction of parts and there tolerances. It will not cancel out movement like a Colt. ( just will not )

Yes, some side to side movement is desirable for bullet alignment.
 

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The lockup should be tighter when holding the trigger all the way back then when the trigger is forward and the hammer down as the pawl/ratchet/hand when the trigger is held back has slid up the ratchet tooth and is on the side holding it to minimize cylinder play. This is as on a S&W. The old style Colts had ratchets with 2 teeth with one for cylinder rotation and the second to push on the ratchet at lockup against the cylinder bolt to firmly hold the cylinder. A little play is desirable in Rugers to allow the bullet to exit the cylinder into and align in the forcing cone.
Perfectly correct. Just visited my favorite LGS, tried a new Smith and a new SP101, and both functioned that way, as do all mine. Plus, the owner confirmed that is the correct way to "measure" lockup on a DA. The Smith was quite loose with the hammer forward and "at rest", but when the trigger was fully pulled it was rock solid, tighter than I've ever seen on any revolver.
 

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Perfectly correct. Just visited my favorite LGS, tried a new Smith and a new SP101, and both functioned that way, as do all mine. Plus, the owner confirmed that is the correct way to "measure" lockup on a DA. The Smith was quite loose with the hammer forward and "at rest", but when the trigger was fully pulled it was rock solid, tighter than I've ever seen on any revolver.


I am hoping that someplace in this discussion we are missing something in our descriptions or how we are relating this.

My three ( GP100---Sp101---SRH ) all have the allowable side to side movement
necessary to function correctly, and they are working and shooting fine.

There is no way on this Earth that pulling the trigger and holding it back removes ANY of the side to side rotational play. Three guns, working perfectly and it ain't happening.

I don't think it was meant to happen.

Let me edit this to say:
The cylinder bolt comes up through the bottom of the frame, it pops into the notch in the cylinder.
If you wiggle the cylinder side to side and there is a bit of play one reason is:
it's caused by the cylinder bolt moving side to side in the frame cut out. the cylinder will torque it side to side. If it's within limits your good to go. What does this have to do with the trigger being pulled ? if the cylinder bolt has a little play in it's cut out it's going to wiggle a tad when you put side to side pressure on the cylinder.
Just checked my three pistols again, they are not worn out beaters with thousands and thousands of rounds through them, one is very new. At rest they all have a slight bit of movement in the cylinder, with the trigger held back they still have about the same amount of movement, ( it's very little ) I guess everyone's idea of Rock solid is different.




Refit Hand: Colt revolvers utilize the hand to lock the cylinder at time of ignition; the hand pushes the cylinder against the bolt, locking it solidly in place. A Colt cylinder, when in full lock, should NOT MOVE AT ALL. This has been referred to as the “bank vault lockup”, and is what made the Colt DA revolvers famous. By the nature of the design, the hand will wear over a period of time and requires occasional replacement. The owner is expected to check the action regularly, and have the hand replaced when it shows any sign of wear. If the gun is used past the point where there is discernible cylinder play, the other parts of the action – the functions of which are all interrelated – will experience uncharacteristic wear, and need to be replaced. This can evolve into an expensive undertaking, and can be prevented by having the hand refit whenever it starts to wear.
 

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Of course, we must allow for some who are unaware of actual revolver operations.
To the OP: see the link for tips on inspecting a revolver:
Revolver Checkout Procedure
This should help you determine if your GP really has too much play in the cylinder. There are also several youtube videos which show the proper way of checking the same, and they clearly illustrate that there is a mechanical difference in lockup of the cylinder, from "rest" to "firing". Hope this helps.
 
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