Seizing Cylinder on GP 100

[Dump1567]

I picked-up this hardly used 2018 7 shot GP 100 from a local shop last week. After putting a few cylinders through it, I noticed in one chamber area that the back of the case head was rubbing the back of the frame as it was coming into the firing position. It was tight enough to prevent pulling the trigger/cocking without a lot of force. I don't think this started happening until I had put a few cylinders through it. And it seemed to be in the same spot. I guess the cylinder isn't lining-up right and is out of sync? I haven't looked the gun over yet but does anyone have an idea of what's going on?
Thanks.

 

[beentheredone]

The fact that you report it started after firing several cylinders-full prompts me to ask the obvious -- have you run a brush through that chamber to see if fouling debris is preventing full seating of the cartridge?

 

[Dump1567]

No. The case looked flush against the cylinder, but I'll check it out during cleaning.

 

[Dump1567]

Well, a good cleaning, and things seem to be GTG. Perhaps the round wasn’t seating all the way?

 

[rugerguy]

...fouling under the ratchet?? headspace in the rear, also check for the front while you're at it,,as noted above,,,cleaning....especially in the chambers too....
then lastly ,the ammo itself....a process of elimination...........

 

[fuzzyedge]

i read that some ammunition case rims were too large for all seven rounds to seat properly in this model GP100

 

[Ale-8(1)]

i read that some ammunition case rims were too large for all seven rounds to seat properly in this model GP100

This is true. There was a lengthy thread about this a few years ago. Ruger never actually admitted it was a problem but did handle a few individual cases quietly.

Basically, the problem was that given the diameter of the "hole circle" of the chambers, some ammo that runs to the upper end of the SAAMI-allowable rim diameter can result in adjacent rims binding against each other, preventing complete insertion into the chambers.

 

[rugerguy]

....not hard to figure out when you have "+/- " a few thousandths and you end up with the opposite extreme at any given time,,,it adds up, no fit..........

 

[Dump1567]

This is true. There was a lengthy thread about this a few years ago. Ruger never actually admitted it was a problem but did handle a few individual cases quietly.

Basically, the problem was that given the diameter of the "hole circle" of the chambers, some ammo that runs to the upper end of the SAAMI-allowable rim diameter can result in adjacent rims binding against each other, preventing complete insertion into the chambers.

I found that thread on the "other Forum". I just tried several different manufacturers boxes of ammo and no issue with seating or cylinder rotation. I'm not really sure what the cause was. I was just grabbing random cased reloads out of a bag when it happened. I'll just pay better attention to what I'm loading in of just use factory ammo I know works.

The other issue I was having was trying to get the sights dialed in. So I need to go back out and work on that with some factory ammo.

 

[Fish]

What about the ejector rod becoming loose?

 

[RoninPA]

The ejector rod on a GP100 can't come loose due to the way it was redesigned (it does not screw into the cylinder as compared to the Six series revolvers).

 

[Dump1567]

So I tried some old PMC marked reloads, and I was able to duplicate the issue of one round not seating. I than switched to some factory new Federal and was able to duplicate the issue once out of 20 tries? I'm not sure what causes it? Maybe the ejector star not lining-up right? Anyway, I'm not going to worry about it. I don't really plan to carry this gun. And if I did, I'll make sure the 7 loaded are seated. But this definitely seems to be suffering from the same issue talked about in the lengthy 2018 thread.

Here's how the PMC look. The new Federal wasn't as bad. These PMC could have also been expanded from firing and contact with the back of the revolver?

 

[jdavis]

By chance has this gun had a lot of .38 spl run through it? If so, a carbon ring can form in the chamber at the case mouth of the .38 case. The amount that the .357 cartridge extends beyond the cylinder looks to be just about right for this to be the cause. Those carbon rings can require a good bit of effort to remove. A tornado brush is useful for this.

 

[rugerguy]

...again, all good points above as to the 'cleaning' and I said a "process of elimination". and you did say above it happened the first time with 'random' reloads .......
as in many cases as noted "it's the ammo".......wish it was here so we could take a GOOD look at it and help you........you're getting 'closer'.........

sorry but the ejector rod on a GP100 has NOTHING to do with a case "chambering" its the chamber itself, or the shell casing ( swelled/bulged) ...loose rod on a S&W will cause the cylinder to NOT COME OPEN, ( BECOMES TOO LONG) and hangs up on the 'bolt', under the barrel, up front........

 

[Hvymax]

It's amazing how many issues are solved by a good cleaning. Ask any gunsmith what solves most problems.

 

[hittman]

What about the ejector rod becoming loose?

That’s a S&W problem, as Ron noted, Ruger’s made different.
For me, this problem is almost always fixed with a cleaning or even hitting the star with a toothbrush at the range.

 

[Johnnu2]

As mentioned before, I would clean under the ratchet and where it 'sits' one the cylinder....in fact all over it more than once. It used to be a normal problem on S&Ws that were shot in competition weekly..... CLEAN after each range session.... even though there are people who will tell you they never clean their guns.

IMHO

J.

 

[Ruger44fan]

Might also want to check to see that the primers on the reloads are fully seated at or below the rim of the cartridge. Progressive reloading without cleaning the cases will sometimes leave some particles in the primer pocket keeping the primer from being properly seated.

 

[Dump1567]

Might also want to check to see that the primers on the reloads are fully seated at or below the rim of the cartridge. Progressive reloading without cleaning the cases will sometimes leave some particles in the primer pocket keeping the primer from being properly seated.

I think that was actually the problem. I ran into the same issue with another gun. Crappy Ginex primers that were extremely hard to seat.