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Tuning Percussion locks and triggers.

Discussion in 'Blackpowder' started by stevelyn, Jul 29, 2004.

  1. stevelyn

    stevelyn Well-Known Member

    Can percussion side locks and triggers can be slickened and tuned in similar fashion as modern triggers to enhance trigger pull and reliability?
    If so who does this type of work and is it something a hobbiest can do on their own?

    Here is my problem. I have a Lyman GPR and while shooting it this winter I found that the hammer was falling to half-cock. At first I thought the lock was full of grease and stiffening up in the cold weather. When I cleaned the rifle and removed the lock for cleaning I discovered there was no grease or cosmoline inside the lock. I cleaned it using MPro-7 and recoated with Militec-1. :barf:
    To slicken things up a bit, I applied a little Brownell's Action Lube Plus to the bearing surfaces of the hammer, sear notches, sear and fly. This seemed to solve the problem. I burned a whole jug of Triple 7 in it and I didn't have a failure again until I cleaned the rifle recently.
    I disassembled the rifle cleaned in the usual manner including the lock. I recoated with Break-Free CLP and let it sit for a couple of days before reassembling. When I put the rifle back together and did a functions check, I found the hammer falling to the half-cock position again. It kept falling and stopping at the half-cock position with the set trigger set and unset.
    I removed the lock again and applied grease to the bearing surfaces as before and reinstalled it. I performed another functions check and this time the hammer dropped to its full travel with and without the set trigger being set.
    As near as I can tell, the problem is primarily with the rough surface of the fly causing the hammer to hang up and fall to half-cock only. A close examination of the lock shows very little finishing work to the surface of the parts.
    I would appreciate any ideas to remedy this. Thanks in advance.

  2. 4v50 Gary

    4v50 Gary Moderator Staff Member

    I'll have to take the lock off to look at it or see a diagram. Give me a couple of days when I get a chance.

    Off the top of my head I would say that the sear spring is too strong and causes the sear to reengage the tumbler after the initial release. I have a repro-Brown Bess that has the same problem (and I've yet to file away at the spring to cure it).
  3. Iggy

    Iggy Well-Known Member

    It may not apply, but....

    Have you tried backing the set trigger adjustment screw off a wee bit?

    Probably won't help, but it would be something to try before filing on things.

    Good luck.
  4. smokemaker

    smokemaker Well-Known Member

    Yes, you can tune a side lock in a similar fashion to a revolver action tune, or at least thats what I've found on my two sidelocks. My GPR has never done the half cock thing, but my Zouave has picked up the nasty habit of the hammer falling from half cock when the trigger is pulled.
  5. 4v50 Gary

    4v50 Gary Moderator Staff Member

    Like the T/C Hawkins, the GPR lock has a coil spring instead of a "V" mainspring. I've yet to really study it to learn how it works.
  6. stevelyn

    stevelyn Well-Known Member

    Yes I did back off the set trigger screw a bit. I intended to anyway to lighten the pull. It did lighten the trigger pull, but increased creep.

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