Lock problems

[JGPrince]

Well I finally got my MVT 1816 barrel/breech plug sorted out. Turns out the plug was NOT in tight. Glad I caught it, that could have been, well, deadly. I honestly can't believe no one gave it the once over, but it is obvious no one checks them. I can say, however, that water no longer leaks out of the breech plug seam. So the musket, again assuming the Indians knew how to build a barrel if not screw in a breech plug, should be safe.

At my request they proofed the musket barrel, and gave me the spec sheet as well as stamped the barrel with NHP for New Hampshire Proof House.

However, the lock is back to its old tricks. That is, it hangs up on half cock and/or will not hold at full cock. I had got by with fiddling with the sear and bridle screws, but every ten trigger pulls it would start hanging up again.

Well, one chronic problem it has is the cock screw keeps coming loose. Well I had it out of the stock, and at full cock, and the screw became so loose I just went ahead and removed it. I turned the lock over, and the cock fell off. This struck me, because in the times I have had the hammer screw off on my Armi Sport 1842 or my Euroarms 1861, the hammer can't even be PULLED off!

Well, for ****s and giggles as they say, I put the lock back in (sans cock) and pulled the trigger. It went click, and the sear moved all the way to no cock. I repeated 7 times, and each time it "fired." I put the cock back on, and it hung up again. Took it off, and it "fired".

Can anyone help me? Pete at MVT is apparently so upset with me over my responses to his personal attack, as well as the fact that out of concern for fellow BP shooters in the wake of the Bess blowing up that I went public, AND that I told him I no longer had faith in his product he refuses to answer any of my emails, so getting help from him is no good.

I want to sell the musket, and as MVT ensures the locks for life I have no doubt that the new buyer could easily have Pete fix it. But I figure I would try to see if there is something I can do on my end first.

Thanks!

 

[J.D.]

Try a tapping a rounded punch on each flat on both the back and front of the square hole to peen it smaller. You might have to resort to filing a bit to make it fit right if you get to aggressive with peening. Just go slow, try and fit until it fits tightly on the square shank of the tumbler.

The square on the front of the cock, where the screw rides, should be ever so slightly smaller than the back.

A set punch will work if you lightly punch two "holes" on each side of the square, but a rounded punch won't distort the metal as badly. Be sure to make the punchmarks on the front of the cock so's they are hidden by the screw head.

Check to see if there is any contact with the wood above the lock. There should be a cut out in the wood to allow the cock to travel freely.

If the cock continues to bind, apply transer color to the lock, work the lock, preferably without the mainspring, and check the back of the hammer and see if the cock is rubbing against the lockplate.

Firing the lock without the cock to stop the tumbler travel can break the tumbler...or other things.

File the back of the cock to relieve that area.

Let us know how things work out.
Good luck,
J.D.

 

[jdstrang]

"However, the lock is back to its old tricks. That is, it hangs up on half cock and/or will not hold at full cock."

Have you checked to be sure the inletting in the lock area is not binding on the "moving" parts? I had a similar problem with my Armi Sport '42 Springfield first time I shot it in the rain. Turned out the wood against the sear/tumbler had swollen just enough to bind on those parts, preventing proper operation. Two minutes with a good wood chisel fixed it...

 

[Ian Pratt]

If it fired consistently with the cock removed (which you shouldn't ever as was mentioned) then immediately hangs up when the cock is replaced, the trouble is likely the cock itself is binding somewhere. Spots to look -

1. The lock plate itself, look for a shiny spot or scratches where things rub, or hold the lock sideways and cycle it, watching for something to hit.

2. The end of the lock bolt , coming through the stock from the sideplate. You'll see a semi circular groove scratched in the back of the cock

3. The cock may be hitting the lock molding or somewhere around it, look for bare wood or a small ding

This can all be caused by the cock getting hit or otherwise bent, replacing a lost lock bolt with one not trimmed properly, on rare occasion by stock swelling or changing. Also can happen if the cock is not mounted square on the tumbler. And of course something may have been faulty right from the start.

 

[JGPrince]

Thanks guys for all the help.

When the lock started doing all this (about 3 days after I got it) I put some bore butter on the back of the lock, put it in the stock, then removed it. I found some of the stuff in the lock inlet, so I sanded down were it was. I figured that would help it.

It did. Then the lock started hanging up again. BUT it hangs up when out of the stock too, so it isn't the stock.

I put the cock back on last night, and really, REALLY tightened the cock screw. Almost made it hard to full cock, but it fired fine. So I kept cocking and pulling the trigger to see how long it lasted. Sure enough, after 20 times or so, it hung up.

I did as you guys said, and checked for binding. THe lockplate looks fine, sans the top behind the flash pan where it is dented from the cock striking in to it when it is fired. It may be that the cock is just mishapen (that would probably be accurate, that wouldn't be the only mishapen thing on this musket). However, that indentation is only struck AFTER it goes to no cock, and it hangs up well before it.

I checked the sideplate screws, and have the one closest to the cock only hand tightened: any more and it will hang up the cock.

As the musket stands now, if one slowly squeezes the trigger it will hang up on half cock. If one makes a deliberate pulling motion, not quite "jerking" but not a slow squeeze, it will usually (8/10 times) fire.

When the cock was off, I checked the entire lockplate face, and found no scratches or marks that would indicate the cock is binding.

Either way I think I'm done with the musket. Not with flintlocks, mind you, but for the same price as my Armi Sport 1842 this MVT gun has just given me too much trouble.

Still, since it will take some time to sell, I would appreciate any further help you guys could give. I just don't get it. I would think if it hung up on half cock something would have to be catching it, but nothing seems to be doing that.

Wierd...

 

[J.D.]

Sounds like the sear is not moving freely. Have you tried backing the sear screw out about a half to a full turn?

Where does the sear spring contact the sear?

With most locks the tip of the sear spring actually travels towards the sear pivot screw as the sear is depressed. While it is essential that the pressure point for the sear spring be as close to the pivot as possible it is also necessary for there to be perhaps 0.010" of space between the end of the spring and the part of the sear that surrounds the pivot screw. Otherwise, as the sear is moving upwards the spring is being subjected to a length-wise compression force (instead of a lateral flexure force) with no way to relieve the stress.

What this means is that it is possible that the sear spring is too long, which will cause binding of the spring against the boss supporting the sear screw. If that is the case, file, or very carefully grind a few thousanths off of the end of the spring. This is a try and fit procedure, so remove a very little from the end of the spring, then fit the spring and work the lock.

That said, I would back out the bridle and sear screw a half turn to a full turn, or maybe more before working on the sear spring.

Another thought, any thick grease, such as bore butter can gum up the works of a lock. Clean the BB off of the lock and use a good oil instead.

One more thought. The cock should not strike the fence. The shelf on the back of the cock should bottom out on the top of the lockplate behind the fence, not on the fence. The tumbler should contact the bridle at the same time as the cock contacting the top of the lock plate.
Good luck,
J.D.