Lone Peak Arms Fuzion: Cocking Issue?

[kthomas]

I'm going to see how @FourT6and2 new cocking piece changes things before bothering Travis about it. It's a very confusing mix of replies in this thread. Some saying theirs do it and it's no issue, some saying it could be 2-3 different issues, and two saying theirs don't do it at all. Very hard to make sense of it all and LP's replies to me weren't that illuminating. They offered to check it out if I wanted since they want to give good customer service but what I really wanted to know was whether it's actually unacceptable bolt behavior in the first place.

I'm honestly not sure if this is something to worry about or not.

If it's affecting the performance of your rifle, from "feel" to reliability, I would want it to be addressed. If not, perhaps its not anything to worry about.

In @FourT6and2's case, it seems to at least affect the "feel" of the action in a detrimental way, which is worth addressing. In his case, I would absolutely be trying to get it figured out, whether that's dealing with LP or his gunsmith. Hopefully that can then guide you on what to do.

 

[FourT6and2]

Who's your gunsmith? Have you asked them about it?

Jon Beanland. Just sent him a message

 

[FourT6and2]

You know... it's happening upon extraction as well, at the same exact spot. So I think it has something to do with the detent in the bolt body ramp that the cocking piece rides in/out of.

 

[FourT6and2]

Jon Beanland gave me a call immediately after sending him the video haha. He said it's 100% normal and that every single Fuzion and even Impacts and Terminus he's built has done it. It just depends on the trigger used and how long the sear is. He said these companies build these actions with enough clearance to run in dirty conditions and because of that, this can happen. But that it's completely fine.

He elaborated that it's also, in part, the cocking piece riding in/out of the detent in the bolt body ramp (as I suspected).

LP's offer to send a longer cocking piece should address it, but as somebody else said earlier, it's most likely just them trying to accommodate a customer complaint, even if there's nothing "wrong".

Maybe I'll try replacing with a Trigger Tech, since apparently that's what LP designed the action around?

 

[NateVA]

Maybe I'll try replacing with a Trigger Tech, since apparently that's what LP designed the action around?

I switched my BnA out and put a TT Special on it and it did the exact same thing, with a tiny bit more firing pin fall. I think the answer is just leave it alone.

 

[just browsing]

Get used to that cock on close boi.

Gotta lighten the lift somehow…

 

[FourT6and2]

Yeah, my gunsmith just sent me video of Impacts and Terminus doing the same exact thing. I'm not concerned anymore.

Two things are happening:

1. The detent in the bolt body ramp, that the cocking piece rides into and out of, is shaped a little differently on every model of action. My Defiance has less of a hump and more of a taper to a flat before going down the ramp. This makes it very smooth. Other actions might have more of a hump, which makes the detent more abrupt.

2. The cocking piece length and trigger sear length dictate how much cock on close there is. Not all triggers have the same sear length and not all cocking pieces are the same length. If you have a shorter cocking piece and a shorter sear length (not height), you'll have more "free fall". If you have a longer cocking piece and/or longer sear length, you'll have less free-fall. The trade off is tighter clearances (might not work as well in dirtier environments) and more firing pin fall (longer lock time).

 

[Secant]

I've been following this loosely. I recently picked up a Kelbly Prometheus that does this upon closing (triggertech trigger). I now need to double check, but I don't think it does this on open. My Ruckus does not (triggertech), and neither do my LPA Razors (triggertechs). Those are the only actions I've checked since I noticed it on the Kelbly.

 

[NateVA]

Yeah, my gunsmith just sent me video of Impacts and Terminus doing the same exact thing. I'm not concerned anymore.

Two things are happening:

1. The detent in the bolt body ramp, that the cocking piece rides into and out of, is shaped a little differently on every model of action. My Defiance has less of a hump and more of a taper to a flat before going down the ramp. This makes it very smooth. Other actions might have more of a hump, which makes the detent more abrupt.

2. The cocking piece length and trigger sear length dictate how much cock on close there is. Not all triggers have the same sear length and not all cocking pieces are the same length. If you have a shorter cocking piece and a shorter sear length (not height), you'll have more "free fall". If you have a longer cocking piece and/or longer sear length, you'll have less free-fall. The trade off is tighter clearances (might not work as well in dirtier environments) and more firing pin fall (longer lock time).

I'm glad he took the time to explain it so well.