Extra click in cap lock action

[bkrauss]

I just purchased a used Lyman Great Plains rifle that is rather old and am in the process of restoring it. One mechanical issue that has presented itself is that in bringing the lock to full cock, there is a click about half way back before reaching full cock. There's no variation in motion or resistance with the click, and it has no relation to the half cock position.

Is there a way to address this, or this something that has come up in other GPR's? It's not an issue of function really, but I do want to understand the function and making of the rifle. I have no experience assembling or disassembling the rifles mechanics, so I wanted to inquire with the more experienced first.

 

[Black Hand]

Does the lock have a fly?

 

[bkrauss]

I don't know what a fly is.

 

[Black Hand]

http://www.lr-rpl.com/index.php?opt...:parts-diagram&catid=41:information&Itemid=68
http://americanlongrifles.org/forum/index.php?topic=6913.0;wap2

Fly ”“ The only function of the fly is to keep the sear nose from falling into the halfcock notch. It is necessary in a lock only if set triggers are used.

 

[bkrauss]

My rifle does have set triggers, however I haven't disassembled the lock before. Is the process of caplock disassembling the same as instructed in your link? If so I could follow that and see.

 

[Black Hand]

Depends. If an older lock, many of the internals would be similar (V-main spring, etc.). Newer (production) locks may use a coil-spring instead. You will need to remove the lock and check the internals.

Disassembling a lock without the proper tools and knowledge can lead to breakage, loss of parts and cursing like a sailor...

 

[necchi]

Disassembling a lock without the proper tools and knowledge can lead to breakage, loss of parts

It's a Lyman Great Plains he doesn't need anything but a needle nose and a screwdriver and he's not going to break anything.
Here's a Thompson Lock that's very similar to the Lyman, showing how to remove the coil main spring;
Relax the lock and remove, easy peasy;
[youtube]JGdAQBsAAzI[/youtube]
You can hear and see the extra click as the sear skips over the flay and half cock.

Here's the fly in a Lyman lock;

It's a good idea to clean old oils out with a solvent and re-oil with fresh stuff.

 

[illuveatar]

I'm with everyone else in thinking that it's the fly. If you're curious I'd suggest taking a look. I doubt you'll break anything, but a proper gun smithing screwdriver might save you from marring the screw heads. Have fun and learn a bit about your gun. :thumbsup:

 

[bkrauss]

This info has all been a great help. I've only cleaned the barrel after use, are there any recommended oils for locks of sidelocks?

 

[necchi]

Just a normal gun oil, I use Hoppes Lubricating Oil.
Won't hurt to pull the trigger too. It's all held in with just wood screws, nothing will "Sproing" across the room.
They use a pretty heavy packing grease at the factory as they have no idea how long a rifle will sit on a shelf, and that stuff can actually slow things down. That's why I recommend a solvent, Brake Cleaner works well.
While you have everything out, reach in with a sharp knife and clean all those little wood bit's out of the mortises, just kinda clean it up a bit.
There's no need for Gorilla tight when you reassemble things back in the wood, just snug is fine.
I should add there's no real need to pull the hammer off the tumbler, it's pressed on pretty tight and you can booger things trying. Just clean and lube the area it turns in.

Any questions come-on back an ask, :wink:

 

[Zonie]

The moving parts in the lock consist of the tumbler which has the half cock and full cock notches machined into its outer surface, the sear which is the pointed part that engages the tumbler notches and the fly which is carried in a notch in the tumbler.

A spring keeps the sear pressed against the outside of the tumbler.

As you rotate the hammer or cock from the fired position to full cock you will hear the nose of the sear snap into the half cock notch.
As it does this, it pushes the fly out of the way.

Rotating the hammer/cock further causes the nose of the sear to ride up and over the fly and then it drops down on the far side. This is the second click. Rotating the hammer/cock further will bring the full cock notch up to the nose of the sear and you will hear it drop into the notch.

If the trigger is pulled a blade on it will push up on the sears arm causing it to rotate out of the full cock notch. This releases the tumbler.

As the hammer/cock falls the rotating tumbler will bring the fly back up to the nose of the sear. When the sear hits the fly, the fly will rotate forward and block off the half cock notch so that the sear cannot enter it.

The sear will then jump over the fly (and the half cock notch) allowing the hammer/cock to fall to the fired position.

 

[bkrauss]

the learning continues! the extra click, I discovered, is the coil spring skipping up where it is notched in with the fly as the hammer almost reaches full cock. It's not a big deal, but I'm glad I discovered the source of the sound. Also, the coil spring is very difficult to remove with the needle nose pliers, so I haven't yet. Will I not be able to get it back in if I do?

 

[necchi]

It's usually not too tuff.
Check the video again, note the hammer is all the way forward touching the lock plate.
The sear needs to go beyond the half cock notch and allow the spring to fully relax.