Issue with used GP100

Help Support Ruger Forum:

davy

Bearcat
Joined
Dec 30, 2022
Messages
6
Location
Belgium
Hi all,

I recently acquired a used GP100 (6" version). This is also my first revolver. The serial number indicates its from 1993, so 30 years old. I took it to the range for the first time, and noticed something odd: at first it worked flawlessy, but after a while, when pulling back the hammer, i noticed that it seemed to have a tendency to block about halfway through the pull. It seems to always work smoothly when firing double action, it only does this when pulling back the hammer for a single action shot.

We are now a few weeks further, and it seems that it starts doing this when it gets used a lot. I had to go abroad for 5 days, and the blocking behaviour was really easy to reproduce before i left. After i came back, the problem seemed to be gone: pulling back the hammer went smooth. But after repeating this multiple times, the blocking at halfway the pull seems to come back.

Has anyone seen this behaviour before, or have any idea what could be causing this? I am planning on taking it to a local gunsmith and have him completely disassemble it for a thorough cleaning/lubing.
 

hittman

Moderator
Staff member
Moderator
Joined
Jan 16, 2008
Messages
16,913
Location
Illinois
Welcome to the forum. (y)

Many carry an old toothbrush in the range bag. Occasionally we'll brush the gunk from on, around and under the ejector star. Not saying this is your problem but its a possibility. Good luck to you.
 
Joined
Apr 2, 2014
Messages
3,201
My first question is does it do it dry firing or only actual?
If only with actual ammo, I'd check the barrel to cylinder end gap to start with, assuming every thing is clean.
Maybe looking at about .07mm as a cold minimum gap with the cylinder pushed toward the barrel, with .12-.15mm as
typical range.
Not sure why you're only feeling it in single action mode.
 
Last edited:
Joined
Dec 8, 2005
Messages
4,414
Location
Lemont, PA, USA 16851
My first thoughts was - during dry fire how does it do? Then if fine with DF, what is the BC gap when cold and what happes to the gap as it heats up. Also, did you disassemble and completely clean, including the trigger assembly? But is sounds like it's either the BC gap or crud under the ejector star. Also look at rhe pawl when the gun is apart and see if there are any wear marks on the sides where it may be contacting the pawl opening.
 

davy

Bearcat
Joined
Dec 30, 2022
Messages
6
Location
Belgium
A friend of mine had a look at it, he is a more experienced gun owner. He was unable to get a piece of paper between the cylinder and the barrel, the front of the cylinder was just too dirty. I started cleaning that side of the cylinder and the ridge of the barrel, and now the gun seems to work flawlessly (y)

I really like the look of this gun, i think i might become a revolver fan. I just like handling this thing, and im really eager to take it back to the range!

And thanks for all the welcoming words!
 

contender

Ruger Guru
Joined
Sep 18, 2002
Messages
25,138
Location
Lake Lure NC USA
Glad to see you got it figured out. Along with the "welcome" we'll remind you to keep the area under the extractor (the "star" so to speak,) clean as well. Often,, there can be crud under there that goes unnoticed until problems arise.

Another tip.

An old gentleman taught me something long ago. (May he RIP) He said,, gunsmiths services are often only needed to clean a gun properly because too many people do not know how or never bother to clean a gun. Gunsmiths make a lot of easy money "fixing" a gun that only needed a good cleaning.
I've bought guns "cheaply" because the owners thought there was a problem with them,, only to easily fix them by a good cleaning.
 

wproct

Single-Sixer
Joined
Nov 7, 2006
Messages
427
Location
Ia
Glad you got your issue figured out with your GP100, they are just such a ruggedly handsome revolver, you get a good one ya want to be sure and keep it! (y)
 

Vintage68

Bearcat
Joined
Dec 12, 2022
Messages
13
Location
Nevada
My son bought me Wolf steel 357 a while back because he doesn't know much about ammo so I thought I'd try them out. In my 6" GP100 (1707) they were difficult to extract. I didn't have to beat them out but it took extra pushing. They were a little less difficult to remove from my SP101. They come right out of my MC GP100.

Shot the two boxes and have never used them again. I do, however, shoot the heck out of steel case 9MM..
 
Joined
Dec 11, 2002
Messages
8,966
Location
Ohio , U.S.A.
yes, good points above, and hard to say "why" unless one looks at all the points, the gaps ( head spaces) the cleaning especially UNDER the extractor 'star' and then the ammo,factory?? reloads, high primers and on and on, types of shelll cases,again "leading".....I recall many years ago, the S&W when first came out with 'stainless' steel DA revolvers, they had issues when things "
"heated up", as I had spent time back then with Mr Wesson himself and he told me of the issues they had when they found out that 4140 chrome -moly steel used in most revolvers and the New" stainless alloys" when heated expended and contracted at different rates, get 'er hot , if too close a tolerance things locked up the LE did NOT like this,,,,, so changes were made at S&W .......lots going on ad you seem to have gotten it solved, so good lucck and enjoy it for what it was made,intended for..........:cool:;)
 

davy

Bearcat
Joined
Dec 30, 2022
Messages
6
Location
Belgium
Sooo ... even though i could not get it to jam again when dry firing, back at the range, it blocked again. The funny thing is that .357 ammo always worked flawlessly, and the .38 special wadcutters seemed to jam up (blocking the hammer again). I went back to the store, they exchanged the wadcutters for S&B .38 special, and those seem to work well (i shot 50 of them without any issue)

So its an ammo thing. Does anyone have any idea how different ammo could cause the hammer to block?
 

HeavyLoad

Bearcat
Joined
Dec 4, 2021
Messages
3
I was going to ask what store exchanges ammo but I see you are in Belgium. Is the ammo factory or remanufactured? I've seen reloads that didn't have the primers seated deal enough and it would cause the cylinder to lock up.
 

davy

Bearcat
Joined
Dec 30, 2022
Messages
6
Location
Belgium
This was using factory ammo. The wadcutters that didnt cut it ( cheesy joke, i know ) were from PPC, the .38 specials that worked are from selier & belott.
 
Joined
Dec 11, 2002
Messages
8,966
Location
Ohio , U.S.A.
there are differences in case rim thickness, high primers? not seated completely, and if the store stood behind the ammo,,,, good for them, just Maybe they saw or knew something was amiss......many tangibles, in either the gun itself or the ammo being used..........(y)
 

davy

Bearcat
Joined
Dec 30, 2022
Messages
6
Location
Belgium
This week it blocked even on the S&B .38's. I contacted the seller, and he is willing to take it back for the price i bought it. Nice gesture, but getting a license for a weapon has a cost of over 100 euros, so even if he takes it back i will be 100 euros lighter.

Tomorrow ill take it to a gunsmith, see what he has to say, and then decide whether i keep it or not. Im hopefull that a thorough cleaning will fix it 🤞
 
Top