failure to ignite cap

[wooly bugger]

Hi,
I recently bought a used Lyman Great Plains Hunter, and the first time I took it out, I found that maybe 1 out of 10 times, it fails to set off the cap. I also noticed that when the hammer falls on the nipple, it's not centered (i.e., the nipple almost touches the edge of the striking surface). Should it be? Are occasional primer failures a fact of life with sidelocks (like with rimfires), or should I expect close to 100% fires?

 

[BlackNet]

things that would cause a failure.
hammer spring to weak,
caps not fitting properly,
nipple clogged up or not allowing the caps to fit on properly,
caps bad,
hammer not striking the caps correctly,

pull the nipple and clean it real good, make sure the caps fit on it good,
check the lock, something may be obstructing it's path and reducing the weight,
check the lock make sure it's in stock good and a tight fit,

 

[robhof]

Look at the back of the lock, the fly is secured by 2 screws, if one or both are loose, the lock will not move in the proper way, also check all screws, tighten and light lube moving parts.

 

[Chawbaccer]

You can heat and bend the hammer or adjust the inleting under the lock to center the hammer over the nipple.

 

[wooly bugger]

Thanks for all the suggestions. On closer inspection, there's definitely an alignment problem. I tried lowering the hammer gently on a cap and it doesn't even clear the edge of the cap! When I shoot, it splits the cap. I'm guessing the easiest way to fix it might be to have a gunsmith adjust the barrel to tang interface. By grinding a fraction of an inch off the face of the tang, it will move the whole barrel/nipple assembly back and fix the alignment problem. I'm surprised that there's such poor fitting on an otherwise well-reviewed rifle.

 

[Chawbaccer]

Bend the hammer or return it. If you set the barrel back you will mess up the alignment of the underlugs.

 

[4v50 Gary]

Bending the hammer is the best option. If you break it, which is why you heat it to soften it, it's the cheapest part to replace (to correct the problem).

 

[arcticap]

Wouldn't shortening the top of the nipple provide just a little more clearance for the lip of the hammer?
Then maybe the face of nipple can be adjusted to be fit flush with the hammer flat.
And make sure that the nipple that's installed is the right one with the proper height.
I would also consider taking down the lip if necessary and all else fails.
A nipple is an inexpensive item to replace while trying to adjust as is a hammer.

 

[Chawbaccer]

I believe geometrically you would want a longer nipple.

 

[arcticap]

I was thinking that if the hammer was hitting near the back lip then a longer nipple would be needed, but if it's hitting too near the front lip then a shorter nipple. But depending on the angle of the nipple you may be right. It's hard to visualize without seeing how steep the angle of the nipple is, how close it is to the lip and at what point in the arc of the hammer fall that it hits.

 

[Wildfire]

Bend the hammer.

They are right.

 

[Smilin Jack]

Check to see if correct nipple. The PO may have put in a longer or shorter one.

My Lyman Great Plains 50 cal caplock has the nipple line up in the middle of the hammer flat spot. The caps go off every time.

A quick visit to a black powder gunsmith can tell you lots.

Dave

 

[GENTLEMAN OF THE CHARCOAL]

You heat that hammer good before you try and go bending on it. Think of it as a piece of good steel you're making a knife blade out of....

 

[madcratebuilder]

I had the same problem on a TC Hawken, bending to hammer is the best fix.