Prefit shouldered barrels

[DLT]

Reading through the barrel nut disadvantages thread, I read a shouldered prefit could be made for certain actions, what actions im wondering such as an arc nucleus, bighorn origin, Mack bros ? One day if I decide to build a rifle I think it would be good to be able to buy a prefit

 

[SKWERLZ]

You definitely can with ARC actions, Zermatt and a few others come to mind as well for being good for prefits.
AI rifles as well.
You’re favorite barrel guy can guide you on appropriate actions.

 

[Rat Rifle]

You definitely can with ARC actions, Zermatt and a few others come to mind as well for being good for prefits.
AI rifles as well.
You’re favorite barrel guy can guide you on appropriate actions.

^“Very good advice“^

 

[AlNyhus]

Reading through the barrel nut disadvantages thread, I read a shouldered prefit could be made for certain actions, what actions im wondering such as an arc nucleus, bighorn origin, Mack bros ? One day if I decide to build a rifle I think it would be good to be able to buy a prefit

Aftermarket actions come with a tenon print. The 'smith chambers the new barrel to that print. On it goes.

Doing your homework on the action before you buy it is important. -Al

 

[762plinker]

the real question is,,,,is the action quality high enough that the numbers are repeatable...are the actions all the sme at the front end( well the bck end too)....if truly built to a spec and the spec is tight and held yes a bbl can be chambered without the action..thus a prefit is possible. my 6ppc bbl are done by my 'smith without the action.

 

[SKWERLZ]

Even with an action that varies enough to be problematic a good smith can see it once, take notes and do prefits after.

 

[DLT]

Aftermarket actions come with a tenon print. The 'smith chambers the new barrel to that print. On it goes.

Doing your homework on the action before you buy it is important. -Al

Well many is out of my price range for sure. I can swing those I mentioned. I figure they will be good enough for me.

 

[jackieschmidt]

For decades in the Short Range Benchrest Crowd. one of Kebly‘s big features with their Stolle Panda Action was you could order a barrel from them, (or follow a print), and be 100% confident that it would screw on and be within the correct dimensions for headspace and bolt nose clearance.

 

[urbanrifleman]

I'm still trying to figure out how to make a barrel to a headspace tolerance of plus or minus 1 thou... Which is pretty standard for these actions. Everyone I asked said the headspace is held to plus or minus one.

If I make a barrel to plus or minus one thou, what happens if you get a plus one action and a plus one barrel? That's headspace.

This idea that these actions have ZERO TOLERANCE, and I am supposed to be able to make a barrel to ZERO tolerance, I am just going to say "no" to that.

 

[urbanrifleman]

Even with an action that varies enough to be problematic a good smith can see it once, take notes and do prefits after.

To what tolerance is the headspace on new barrels?

 

[jackieschmidt]

I'm still trying to figure out how to make a barrel to a headspace tolerance of plus or minus 1 thou... Which is pretty standard for these actions. Everyone I asked said the headspace is held to plus or minus one.

If I make a barrel to plus or minus one thou, what happens if you get a plus one action and a plus one barrel? That's headspace.

This idea that these actions have ZERO TOLERANCE, and I am supposed to be able to make a barrel to ZERO tolerance, I am just going to say "no" to that.

That’s a .002 tolerance.

With proper tools, that is not a big hurdle.

 

[SKWERLZ]

To what tolerance is the headspace on new barrels?

I measured two 700’s last month that were .011 different from bolt face to action face.
Add differences with various lugs and it could get worse.

Prime candidates for remage barrels.


My ARC action is +.0003 from print, I’m good with that!
Lol!

 

[urbanrifleman]

That’s a .002 tolerance.

With proper tools, that is not a big hurdle.

I'm not saying it is.

I'm saying is the action is .002 tolerance and I make a barrel at .002 (same as the custom action).

That's .004 total.

 

[Dusty Stevens]

I measured two 700’s last month that were .011 different from bolt face to action face.
Add differences with various lugs and it could get worse.

Prime candidates for remage barrels.


My ARC action is +.0003 from print, I’m good with that!
Lol!

What if your bolt nose is on the other end of the spectrum, how much is too much if youre trying to fit a nut barrel to a remington bolt nose?

 

[Dusty Stevens]

I'm not saying it is.

I'm saying is the action is .002 tolerance and I make a barrel at .002 (same as the custom action).

That's .004 total.

Its only as good as you can measure. Shoot for zero and all is good. They fit every time

 

[urbanrifleman]

Its only as good as you can measure. Shoot for zero and all is good. They fit every time

I always shoot for zero. That's really not the point. On a match chamber job? I'm shaking my head.

I've been told by customers that "I was told anyone can make a barrel for my action".

The mechanical engineer in me is just at a loss for this total disregard for tolerances.

 

[Dusty Stevens]

I always shoot for zero. That's really not the point. On a match chamber job? I'm shaking my head.

I've been told by customers that "I was told anyone can make a barrel for my action".

The mechanical engineer in me is just at a loss for this total disregard for tolerances.

Well if you make it to the spec on the print you only have their million dollar machine tolerance which on a tenon its close enough brass interchanges and the engraving lines up

 

[LVLAaron]

Aim for +1 or 2. On my personal rifles I cut +1-2. Gives me a thou for crush, and a thou so I know I'll have enough resize die length to get the brass where I need it.

I don't think a thou or two is going to be a differentiator to someone blindly ordering a barrel. If it's an action you have known good measurements for.. hit your numbers and keep the barrels consistent from one to the next for that action.

 

[AlNyhus]

Well many is out of my price range for sure. I can swing those I mentioned. I figure they will be good enough for me.

DLT, you mentioned Mack Bros.

Randy Robinett just did a barrel for my Mack Bros. Gen1 single shot. The tenon print supplied with the action was dead on. It's in the Pro Bed now. -Al

 

[SKWERLZ]

What if your bolt nose is on the other end of the spectrum, how much is too much if youre trying to fit a nut barrel to a remington bolt nose?

Good point but normally there’s enough clearance there to accommodate anything but a grossly wacko example

I had to make a fixture to measure that similar to the datum on a cartridge shoulder( assuming they kept a consistent angle,,,lol!) and they were fairly close but that could certainly get you.

I’d love to hear about various actions and their variance’s from those who see a ton actions regularly.