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Old January 9, 2013, 08:08 AM   #1
rrruger
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GP100 light primer strike?

What part, if any, would the transfer bar play in light primer strikes?
Could a burr or friction prevent enough energy from reaching the firing pin to cause a light strike?
Would it be advisable to polish the transfer bar to a mirror finish? perhaps polish the channel it rides in?

Thanks for any input.
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Old January 9, 2013, 10:15 AM   #2
Slopemeno
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Is the gun completely stock?
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Old January 9, 2013, 10:24 AM   #3
Don P
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Quote:
Is the gun completely stock?
I concur. To give advise or possible cause much more info is needed
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Old January 9, 2013, 12:26 PM   #4
Scorch
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Generally, the condition of the transfer bar has nothing to do with light strikes. It fits loosely in the hammer cutout and is not pinched by the hammer when fired. If you are consistently having light strikes, and the gun has never been modified in any other way (springs, trigger job, etc) Ruger will fix it for free. If you have had work done, or just want to do it yourself, you can take some 220 to 320 grit silicon carbide paper and slowly sand down the hammer nose until you have a bit more firing pin protrusion. But be careful, .005" will make a great difference, so proceed slowly.
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Old January 9, 2013, 08:55 PM   #5
rrruger
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Interestingly enough, the hammer spring was lightened to a Wolfe ten pound spring and worked fine (zero misfires for 400 rounds or so). Then it started missing about two in a hundred using the same Remington 125 HP 38 Spec rounds.
I moved back up a bit to the 12 pound spring but I am still missing on about 2%.
I have added hammer shims because I was seeing contact marks on the left side of the hammer. even with the hammer shims the hammer is still dragging slightly on the left side. I wondered if the hammer spring strut might be pushing the hammer slightly off center as it cammed forward, but everything in the strut pocket of the hammer looks clean.
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Old January 10, 2013, 10:48 AM   #6
Don P
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Simple fix after your follow up post. Install the factory spring (14 lb.), or start reloading and use Ferderal primers.
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Old January 11, 2013, 11:04 AM   #7
rrruger
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Simple fix after your follow up post. Install the factory spring (14 lb.), or start reloading and use Federal primers.
Not the answer I was looking for...But I'm sure it's the correct answer!
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Old January 11, 2013, 04:17 PM   #8
Picher
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I haven't worked on the GP100, but found the light firing pin strike problem on Blackhawks that had trigger work to lighten pulls and balance the trigger spring to reduce backlash. The transfer bar wouldn't move fully upward because there was no backlash (that a factory pull commonly has, to get the bar high enough to adequately transfer force to the firing pin). Installing a trigger stop could also create the problem.

The way I often fixed the problem was to remove the transfer bar, heat it just short of red hot, then lengthen it by peening. After peening, it may need to be ground/polished smooth. Casenit can be used to harden the end that's struck by the hammer, preventing deformation.

(In older transfer-bar system guns, the transfer bar might be deformed by hammer strikes to the point that such light strikes can occur in unmodified handguns. Replacing the transfer bar usually takes care of the problem.)
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Old January 11, 2013, 04:45 PM   #9
Ifishsum
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My brother-in-law has a GP100 - unmodified - that would not reliably fire the reloads that we made with CCI primers - there would be an indentation in the primer, not quite what I'd call a light strike but definitely not as deep as it is on my .357s (which have always fired my ammo just fine). It hasn't misfired with any factory ammo but it definitely does not hit the primer quite as hard as it probably should. He didn't want to send the gun back, especially since it seems to fire factory ammo without any trouble - so we tried Winchester primers for his loads and they have been 100% reliable so far.

It would probably bother me enough to have it properly fixed at some point, but in the meantime it's worth trying another brand of primer if you can find some. Federals are generally believed to be the most sensitive, and Winchesters also seemed to work in our case.
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Old January 14, 2013, 01:01 PM   #10
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I had a guy bring in several hand guns all with the same problem.
After test firing them and they all worked fine. come to find out he was using small rifle primers, and a friend did the trigger jobs just by lightning the main spring.

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