I just bought a used CVA Kentucky rifle stock that came with a Maslin percussion lock. I've checked it over and I can get either half-cock or full-cock but not both. It appears the previous owner has tried to make adjustments as some of the screws don't look like they belong to it. Without taking it all apart I can't tell if it is badly worn or poorly adjusted. Any ideas? I'll look online for the parts that match the lock I have.
Percussion lock problem
- Thread starter Catcar67
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entropy
Member
First, get all the gunk out of the action. It may work better then. Are you saying if you pull the hammer back to half-cock, you can't pull it from there to full cock? Or be able to drop the hammer manually (thumb on the hammer) to half-cock from full cock? When you pull the trigger, are you holding it back until the gun fires? That should make the sear clear the half-cock notch. Except for the gunk on the action, I don't see anything that would cause what you describe. It's a standard CVA percussion lock, it appears everything is there.
Papa G, it does have a trigger return spring, it serves the same function.
Papa G, it does have a trigger return spring, it serves the same function.
noelf2
Member
^^^ Not sure what you mean by this. If you can get it in half cock (which it looks like you can), and you can get it in full cock (which you say you can), then all is good. It may just be my eyes, or the picture, but the tip of the sear looks blunt or chipped. I'm thinking you can get the sear to engage the half cock notch, but not the full cock notch. Is that so?
Loyalist Dave
Member
FIRST..., does the problem happen with the lock in the stock, AND out of the stock, or only when it's in the stock? If it only happens when it's in the stock, then you have some wood from the stock interfering with the mechanical portions of the lock, and you need to do a bit of scraping of the wood inside the lock mortise. IF it happens also when the lock is removed, the problem is in the lock parts themselves. Complete disassembly, cleaning, reassembly is the first step. It's amazing at how little crud is needed to give you fits with the internals on a lock. Sometimes when cleaning you will find by observation a portion on a part or parts that shows damage, and will answer your question.
LD
LD
In reply to all. I can adjust the lock screw to get full cock but then the hammer won't hold in half cock. If I adjust the screw to get half cock, then the hammer won't latch into full cock. In the second adjustment the fly is pushed back by the sear lever and the hammer drops. In the first adjustment the sear won't sit into the notch on the tumbler. I've cleaned out the lock curd so now I can see the fly working. When in full cock the sear is resting on the fly. Is this how it's supposed to work?
Loyalist Dave
Member
Well, Normally...., the tumbler, that part with the notches, is too hard to file, and was probably messed up by the previous person with a motorized, grinding tool. Either with a dremel or something more harsh.
IF I can make a suggestion, I'd try to "stone" the groove, and also to look for a replacement part. Try getting both of these stones https://www.brownells.com/gunsmith-...tones/6-x-1-2-x-1-2-india-stone-prod9622.aspx as stoning will work on hardened lock parts, and is slow so you don't make things worse. Now it will drive you a bit crazy, as it's slow, but you will avoid causing worse damage, and you may want to polish other parts of the lock as well, such as the side of the sear where it rubs against the lock plate, etc.
LD
noelf2
Member
Just for reference, this is one that I have in my box-o-locks. CVA but the parts look a tad bit different. Showing you this one in full cock for reference, so you can see what the full cock notch should look like. I have the wrong sear spring in this one, temporarily, so I could test it.
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Thanks, Noelf2, I did get mine apart. Apparently, the whole top portion of the full cock notch was broken off. I smoothed the portion of the tumbler where the sear rides and was able to file a slight notch where the sear is supposed to sit. I can Dremel a little deeper notch but right now the sear contacts the fly before it engages in the new notch. If you draw a line in your photo from the point of the sear to the sear-side edge of the fly, you'll see how much of the sear notch was broken off. So far I haven't been able to find a tumbler like the one in my photo that has the adjusting screw. I know the fly's purpose is to keep the sear from engaging the half cock on firing so I'm going to try to leave the fly out and work the lock by hand.
arcticap
Member
Is this tumbler on eBay the same as yours?--->>> https://www.ebay.com/itm/CVA-Hand-L...=item1cc5b33ab0:g:Un0AAOSwoPtbHCur:rk:18:pf:0
This Maslin lock on eBay with close up photos seems to be the same as yours:--->>> https://www.ebay.com/itm/CVA-Maslin...tyMailSmallFlatRateBox!06052!US!-1:rk:13:pf:0
This Maslin lock on eBay with close up photos seems to be the same as yours:--->>> https://www.ebay.com/itm/CVA-Maslin...tyMailSmallFlatRateBox!06052!US!-1:rk:13:pf:0
My tumbler has the adjusting screw. The Maslin on ebay doesn't show the screw. I just bought another tumbler on ebay. It's not a direct swap replacement but I think I can make it fit. Also, I did pull the tumbler out and Dremeled in a new notch (it's not as deep as the original but I'll get it into the stock and give it a try.
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I tried the "re-ground" notch without the fly installed and the lock caught on the half-cock notch. I'll re-assemble and try it again. Apparently, the stock I bought did not come with the Maslin lock as the mounting screw holes do not match. I bought a different lock (one that doesn't use the fly and bridle) with the correct hole spacing just in case my engineered tumbler doesn't work right. Since the early Kentucky rifles were built for shorter people (trigger to stock butt length), I built a brass 2" extension to lengthen the stock. When I get some of the lock set sorted out, I'll give an update and have pictures.
The new tumbler arrived and I made the necessary modifications to it so it would fit into the Maslin lock (the replacement tumbler needed a stud to fit into the bridle). After some adjustments on trigger pull, it's working like it should. Here's the photo of the stock extension I built.
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