Lone Peak Thread Issues?

[Buffalo-Jo]

I picked up a lone peak fuzion medium action that I intend to build a 6.5PRC on. I ordered a top teir barrel from a pretty reputable barrel supplier which also cuts them to pre-fit specifications. Until resolved, will remain nameless, just looking for additional insights.

I got the barrel last week and decided to make sure that everything threaded up together before actually fitting it up. I'm still waiting on other components so wasn't in a hurry to get everything formally fit up. I was able to get the threads to start about 1 rotation before they were locked up solid. I pulled it apart, cleaned and greased the threads more meticulously and still locked up at ~1 rotation. I didn't have the barrel in a vice and was only threading by hand so no damage was done to threads.

I called the supplier and they said that Lone Peak was known to cut the threads in the action shallower than what they should.

Here are the measurements I pulled on the action and the barrel

• Action inner diameter (ID) - 0.996" - would be the peaks of the internal threads
• Barrel shoulder - 0.979"
• Barrel Tenon outside diameter (OD) - 1.062" - measured using the wide part of calipers
• Tenon Thread valley - 1.011" - depends on how sharp my caliper beveled points are and slight angle to calipers to stay in the same thread path

Based on my measurements, the barrel will never thread on due to the Action internal diameter being smaller than the tenon threads?

So a few questions for my fellow roksliders

• Is this an accurate enough way to access the problem so I can figure out if I need to get the barrel worked on or the action?
• Has anyone else ran into this issue with lone peak actions?

 

[wpeach1912]

I’d call lone peak and the barrel manufacturer and let one of them figure it out. Lone Peak usually has pretty good CS

 

[JohnJohnson]

Has anyone else ran into this issue with lone peak actions?

Before I got my LP I did pretty exhaustive research into it and never heard this mentioned. Also, if it's such a known thing to the gunsmith why didn't he take that into account when cutting the threads for the barrel? It kind of sounds like damage control on his part to me but who knows, maybe it's true.

 

[wind gypsy]

I picked up a lone peak fuzion medium action that I intend to build a 6.5PRC on. I ordered a top teir barrel from a pretty reputable barrel supplier which also cuts them to pre-fit specifications. Until resolved, will remain nameless, just looking for additional insights.

I got the barrel last week and decided to make sure that everything threaded up together before actually fitting it up. I'm still waiting on other components so wasn't in a hurry to get everything formally fit up. I was able to get the threads to start about 1 rotation before they were locked up solid. I pulled it apart, cleaned and greased the threads more meticulously and still locked up at ~1 rotation. I didn't have the barrel in a vice and was only threading by hand so no damage was done to threads.

I called the supplier and they said that Lone Peak was known to cut the threads in the action shallower than what they should.

Here are the measurements I pulled on the action and the barrel

• Action inner diameter (ID) - 0.996" - would be the peaks of the internal threads
• Barrel shoulder - 0.979"
• Barrel Tenon outside diameter (OD) - 1.062" - measured using the wide part of calipers
• Tenon Thread valley - 1.011" - depends on how sharp my caliper beveled points are and slight angle to calipers to stay in the same thread path

Based on my measurements, the barrel will never thread on due to the Action internal diameter being smaller than the tenon threads?

So a few questions for my fellow roksliders

• Is this an accurate enough way to access the problem so I can figure out if I need to get the barrel worked on or the action?
• Has anyone else ran into this issue with lone peak actions?

I dont know if your measuring methods are accurate enough but that tennon thread valley seems too large? Google suggested that minor thread diameter should be in the neighborhood of 0.0988". Maybe measuring depth of valley on one side and extrapolating for the other side would get you better measurements?

Tell me SJA didn't do the barrel.

 

[WeiserBucks]

• Is this an accurate enough way to access the problem so I can figure out if I need to get the barrel worked on or the action?

Which one do you consider disposable?

 

[Raider4044]

Measuring with calipers is not really helpful. Any reputable smith can check the barrel threads with a ring gauge/thread mic and tell you pretty quick if they are within spec. Same can be done on the action with plug gauges.

If the barrel’s out of spec, then it’s an easy fix.

If the action is the issue, I would send it back to Lone Peak and have them fix/replace it if you want to be able to run prefits. If you don’t care about prefits, the barrel can just be threaded to fit for the action rather than to class 3a spec. Not that big of a deal, your smith will just need the action in hand.

My bet is on the barrel being out of spec.


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[cq0302]

Tell me SJA didn't do the barrel.[/QUOTE]


Not SJA


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[Quandary]

I have two Lone Peak actions a Razor and a Fuzion. They are both identical in threading and headspace. In fact I can switch barrels between both actions and they headspace perfectly.

 

[ckleeves]

Weird things can happen but I would doubt it’s the LP.

 

[waspocrew]

Agreed ^^^ I would doubt it's the LP as well. More than likely, the barrel is out of spec.

 

[Buffalo-Jo]

Measuring with calipers is not really helpful. Any reputable smith can check the barrel threads with a ring gauge/thread mic and tell you pretty quick if they are within spec. Same can be done on the action with plug gauges.

If the barrel’s out of spec, then it’s an easy fix.

If the action is the issue, I would send it back to Lone Peak and have them fix/replace it if you want to be able to run prefits. If you don’t care about prefits, the barrel can just be threaded to fit for the action rather than to class 3a spec. Not that big of a deal, your smith will just need the action in hand.

My bet is on the barrel being out of spec.


Sent from my iPhone using Tapatalk

Will the three wire method get me similar information as the thread mic?

 

[Raider4044]

Will the three wire method get me similar information as the thread mic?

Yes, three wire method with a standard micrometer will work as well.

 

[Buffalo-Jo]

We measured it out at 1.0226” on the pitch diameter using the three wire method. Which would be outside acceptable tolerance according machining doctor .com for 1 1/16” 16TPI 2A threads. https://www.machiningdoctor.com/threadinfo/?tid=121

 

[Buffalo-Jo]

Turns out it was the action. Lone peak replaced it and covered return FFL costs. Don’t actually know what the issue was, but it didn’t pass when they checked it.

The southern precision cut Bartlein prefit threaded right in once I got it home.

 

[wind gypsy]

Thanks for the follow up. Bummer that Lone Peak let that out.