excessive cock on close, **updated/resolved**

[Pete Wass]

It is often difficult to help anyone because of perceptions and terminology. This is a pretty good example of that.
Pete

 

[Pete Wass]

Kelbly actions have always been a cock on close action. That is if you set it up with the recommended pin fall it will have cock on close.

So, what is the correct way to express the problem this lad is experiencing?

 

[Kevin1990]

Called kelblys this morning and talked to Caleb. You where all correct. Super nice guy. I described the issue in detail. He said it sounds pretty normal. “Have you tried putting it in a stock you’ll be using? I must have sounded sad when I said “okay, I’ll try that.” Because then he said, “send it in anyway, with a note, and let’s take a look at it, to make sure everything is in working order.”

I think he was more concerned about me not having the action to be able to go and shoot with. So in closing, it’s probably normal, but even if somthing is wrong, I’m honestly glad I have an action with customer service like this backing it.

 

[WSnyder]

So, what is the correct way to express the problem this lad is experiencing?

I’d say by the video he posted he has the typical cock on close. I suspect we had some miscommunication as to taking measurements when trying to determine how much.

 

[Kevin1990]

I’d say by the video he posted he has the typical cock on close. I suspect we had some miscommunication as to taking measurements when trying to determine how much.

would cock on close make the cocking piece protrude more after the action hitches and starts going downward? cause once it catches and goes over the "bump" I described it protrudes more.

now im curious how long Kleblys will have the action for. Not that I care. I still need a barrel and chassis.

 

[WSnyder]

would cock on close make the cocking piece protrude more after the action hitches and starts going downward? cause once it catches and goes over the "bump" I described it protrudes more.

Yes

 

[Florida Wally]

would cock on close make the cocking piece protrude more after the action hitches and starts going downward? cause once it catches and goes over the "bump" I described it protrudes more.

now im curious how long Kleblys will have the action for. Not that I care. I still need a barrel and chassis.

I sent an action to them a few years back and I got a response quickly, as I remember, the day after it was delivered to them. No problems with the action and they shipped it back to me the next day. I think you are correct, they want you out shooting your rifle and are concerned with you not having the action to be able to go and shoot with. There are many posts on this forum about Kelbly’s excellent customer service and they are well founded.

 

[Tim Singleton]

I’d like to know just how to measure cock on close with a Bat B action. I’ve never been clear on this topic myself. Anyone care to jump in ?

On the Bat the pin sticks out of the cocking piece as a cocked indicator
take a small pin gauge or a small drill bit stick on top of the pin the measure to the cocking piece when cocked. With the base of your calipers. Dry fire then repeat the measurement. Subtract one from the other and that’s the fall

 

[Stumpy1]

While we are sorta-kinda on the topic, how much pin fall is too much, and what would be the result?

Thanks in advance!

Frank

 

[AlNyhus]

I have a nice video of cock on close. I'll see if I can get it to post here. The last time I tried this site needed it converted to a different format.

 

[Tim Singleton]

Oh cool’ I’ll do that, now how should I measure the cock on close?

Same method. Take a measurement as you close the bolt just before the pin begins to move back. Then measure when cocked

edited to try to make more clear

 

[Florida Wally]

@Kevin1990 Maybe this video will help you a little. After Ian installs the trigger, watch closely, you will see a “hitch” when he closes the action to dry fire. He does it quickly, but it is similar to your video.

 

[Edd]

When measuring cock on close, you have to consider the thread pitch on the bolt shroud. As you rotate the bolt handle down, the bolt shroud is pulled forward by the lugs but it is also moved to the rear by the threads.

 

[WSnyder]

Sounds confusing..before the pin moves = open bolt pin protrudes 0.0445 ?
As the bolt begins to close on the cocking ramp the pin protrudes 0.054 beyond the shroud.
Closed bolt 0.039

As you close the bolt you need to stop just as the bolt lugs pop over the top of the abutments in the action. As said above as you continue to rotate the bolt the shroud will continue to move back.

 

[Tim Singleton]

I think I got it, ( maybe lol) it really feels like a tiny little spot.
Open 0.0445
The little spot just before the bolt rotates measures.
0.049

If the pin does not continue to move rearward as you close the bolt you have zero cock on close

 

[Kevin1990]

@Florida Wally Ha! I watched that video before posting here and thought, awesome! same thing with mine, but it kinda looks like he irons it out with a sear adjustment...possibly. I tried doing that with my shilen BR trigger and did not find success. after watching it again he manipulates the bolt faster so its hard to tell. but even after the sear adjustment right at the 2:46 mark, it looks like it still does the same thing mine is doing. If all is well, ill at least have some peace of mind.

 

[Tim Singleton]

@Florida Wally Ha! I watched that video before posting here and thought, awesome! same thing with mine, but it kinda looks like he irons it out with a sear adjustment...possibly. I tried doing that with my shilen BR trigger and did not find success. after watching it again he manipulates the bolt faster so its hard to tell. but even after the sear adjustment right at the 2:46 mark, it looks like it still does the same thing mine is doing. If all is well, ill at least have some peace of mind.

It really doesnt feel that bad once its in the stock

 

[Alex Wheeler]

The easiest way to measure cock on close accurately is at the front of the action. Bring the bolt handle down until the trigger catches the cocking piece, measure from the action face to bolt face. Then fully close the bolt and measure again. Its harder to do at the shroud end because on a threaded shroud its backing up as you close the bolt and if you dont take that into account you will think you have less than you do. Also remember, the cocking piece is not moving back the bolt is moving forward with cock on close. I no longer time Kelbly actions, but I have timed a lot of them over the years and know their design inside and out.

 

[jackieschmidt]

The most notorious custom actions suffering from lack of sufficient firing pin travel were the first generation Farleys, Of which I have two.

They also have way too light of firing spring pressure.

This could be fixed, but due to the rather shallow cocking helix, you had to settle for cock on close.

I did this by offset bushing the hanger, moving it back the required amount to get at least .230 inch fall.

some twenty years ago one of my good friends got a brand new rifle built on a Farley. It was slick. It was smooth. You could effortlessly flip that bolt open, and closed.

It would not shoot worth a sh-t.

We took it to my shop, offset bushed the hanger to move the trigger back, and made a spacer to shim the firing pin spring.

It ended up with .240 inch pin travel and 24 pounds of static spring pressure.

Now granted, you could no longer just flip that bolt open, and it had considerable cock on close.

The first group he shot with it upon returning to the range was about a .080.

Granted, there might have been a better way to cure it’s ills, but he loved it.

 

[Kevin1990]

action made it to kelblys yesterday, and got a notification that it will be back to me on Friday. No phone call or anything. So I imagine it was completely fine. Perhaps there’s an explanation in the box, but I’ll give em a shout tomorrow.