XP 100 Rebarrel (Full Length Tennon)

[CFCA1237]

Hi Guys,

Who here has re-barreled an XP 100 pistol?

The factory barrel tennon threads on a current project are turned down rather crudely to give clearance for the front action screw. Has anyone rebarreled an XP and ran full depth threads similar to a 700/40x? I have heard of people milling a small relief in the tennon threads to give clearance for the action screw. Thoughts? Is anyone just fitting them precisely so the screw maximizes "bite" but doesn't make contact with the tennon? How are you guys approaching this?

Any pictures or thoughts would be awesome.

 

[ridgeway]

I make a normal 700 type tenon and the normal 10 thou clearance for boltface and counterbore diameter. Just make sure your action screw does not contact threads. Makes no sense how remington machines XP tenons.

 

[Dusty Stevens]

Just make em like a 700 and put the correct length screw in it

 

[Preacher]

Done lots of them and never made em look like a XP tenon...
IF the screw touches the tenon all bets are off.....

 

[CFCA1237]

Has anyone ever milled a small relief in the threads? Seems like it would be super simple to do. Would that be a common practice?

 

[GenePoole]

Am I missing something? Isn't it like the front screw in an R700? Wouldn't it be easiest to just grind down the screw a little? I do this all the time for R700's.

 

[paperpuncher]

Am I missing something? Isn't it like the front screw in an R700? Wouldn't it be easiest to just grind down the screw a little? I do this all the time for R700's.

Not the same because the action shorter the front action screw is over the tennon so if the frt action screw is too long it will contact the tennon. The factory barrels have a few threads turned down to give more clearance

 

[gunsandgunsmithing]

Am I missing something? Isn't it like the front screw in an R700? Wouldn't it be easiest to just grind down the screw a little? I do this all the time for R700's.

Yes. The issue with them is that there's only about 3 threads in the front hole to hold it. You want to use all of it! Cut the screw a tad short and you can strip the threads. A tad long, and it hits the barrel tenon, potentially causing a gall and certainly won't do anything good for accuracy, either.

I've done them different ways and they all seem to work. One way is to turn the major od down a bit at the screw location. The idea being, leave the pitch diameter aloe, where the load is and the tops of a thread don't do anything, anyway. So, you can turn the major in that area to about 1.030 and gain about .015 clearance for the screw without giving up any strength of the joint. That's just one way. But you don't want to try pulling the barrel while the screw is still in there with any protrusion. That'll make for a bad day.

 

[CFCA1237]

Anyone mill a small relief in the threads or is that not done? Torque the barrel on, center punch, mill a small relief for more clearance. Thoughts?

 

[Sniper338]

 

[Sniper338]

Trued xp100 with ptg aftermarker bolt

 

[CFCA1237]

You are amazing. This makes so much more sense. Thanks for the pics. Great info

 

[Sniper338]

You are amazing. This makes so much more sense. Thanks for the pics. Great info

Glad that helps. I read the post and thought.. I got my 6.5x47 lapua barrel sitting on my dresser.

 

[Roeder]

Anyone mill a small relief in the threads or is that not done? Torque the barrel on, center punch, mill a small relief for more clearance. Thoughts?

Yes, I have done exactly that on other small actions that have this issue. The factory barrel I removed from one had a flat machined in the threads at the place the screw would contact. I think it was a Cooper. I just made the new barrel tenon look the same. It won't hurt a thing as long as you carefully deburr the threads after milling the flat.

 

[Ggmac]

Remington made the relief cut on 788 also . I , at one time would use a grade 8 stud on the receiver , loctite it in the correct depth and use a hex nut or slotted fastener on the stud . Never had to worry about compression of wood or bedding materials upsetting the depth and hitting the tenon threads . I still do it on some 22s and use a knurled thumb screws .

 

[hogpatrol]

That part of the front screw that protrudes in to the milled clearance, what is it's function? Like Chuck said, makes no sense whatsoever. Cut the screw to the proper length and bolt it to the stock.

 

[dgeesaman]

Anyone mill a small relief in the threads or is that not done? Torque the barrel on, center punch, mill a small relief for more clearance. Thoughts?

I have an XP100 style action and due to my inexperience I pushed a couple of the threads down when I was trying to get the action screw length correct. No way that barrel was going to turn out without major damage.

My gunsmith was able to clear the problem by spot milling through the action hole, but we weren’t sure if that would be good enough. It did work but if you’re going to do it, do it with the barrel out of the action and deburr the threads well.

 

[hogpatrol]

Measure twice, cut once.

 

[dgeesaman]

Measure twice, cut once.

Thread crests are easily deformed, and turning a screw with your fingertips generates far more axial force than you might think. So I learned you literally can’t feel the screw crush the threads.

 

[hogpatrol]

Thread crests are easily deformed, and turning a screw with your fingertips generates far more axial force than you might think. So I learned you literally can’t feel the screw touch the threads.

Could you have used calipers to check the depth? Just curious.