Mountaineer .45 1:20 twist barrel

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I'm just not sure how interchangeable everything from my disc extreme would be on the mountaineer barrel. It sounds like the bolt would work, if I get a mountaineer breech plug. I would have to do some inletting to the stock and bed it. But I've bedded other guns before, so that doesn't worry me too much. Would the trigger assembly from my gun work?

Most stuff will interchange but tolerances over the years can vary. Never had a issue swapping triggers. Bolt fits. Stock probably needs inletting around the front half of the recoil lug.
Notice how the lug is forked? Its wider and longer than an Extreme lug.
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Breach plug wont swap. Mountaineer plug is longer. Lehigh's Mountaineer plug is $24.45 shipped to your door. You will need either a bare primer bolt body or a Lehigh red jacket adapter for your bolt. The adapter is $14.50 so if you go that route buy it with the plug. Good idea to get 2 actually in case you lose one. The other option is the bare primer bolt body from Sportsmans for $85 shipped. Your bolt internals will swap right into it.

My headspace using a old Elite bolt is a tiny bit too tight. Should be a pretty easy fix though. I will find out today. Worst case....10-20 thousandths will need to come off the plug. I would rather have it too tight than too loose.
 
Macegl, you know I would really tell you to try it first. If it has been installed correctly it really should work. GM barrels and TC barrels are built differently.
 
I'll try it for sure. My last hunt will be over this week, so hopefully I should have some time to get out and try it.
 
There is more than one way to skin this cat and the first one worked as you will see. I will try the other in a bit. Tree trimmer guys are here removing lots of invasive honeysuckle for me and doing yearly yard waste removal.

Here goes. This is a beautiful Knight bare primer bolt body. Machining is pretty nice actually and looks far nicer than older bolt bodies. Appears to be machined out of stainless and not cast then plated.
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With my Elite internals no problem. Screwed right in no mods needed.
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So how does it fit?........PERFECTLY
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Headspace can barely be seen and looks about as perfect as i could hope to get.
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But the proof is in the primer. This is a standard CCI209 i test fired.

Basically spotless and falls right out after firing.
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Macegl, you know I would really tell you to try it first. If it has been installed correctly it really should work. GM barrels and TC barrels are built differently.
Sabotloader beat me to it.

Even though I would not do that either, As long as the smith/machinist indicated the barrel in the lathe on the Bore it should be symmetrical and should work just fine. Not being indicated on the bore is what messed up the QLA on the TC rifles, as it caused them to be off centered.
 
Well that's a 1st, shame to do that to a barrel but I guess if all your gonna do is shoot sabots it does make loading easier. Also said as long as its concentric with the bore it should shoot conical bullets just fine..
 
I had some Brass Lehigh's that did that back in 2008ish, and they still ended up wanting to go sideways. I'm sure copper would do better. ALL LOADS WERE 120 GRAINS BY VOLUME.

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SST's straight out of the box. The 300 grainers are one holers.

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And some XTP MAG's as well.

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All were 3 shot groups. Sabotless, in my .45 cal 1:20. ALL LOADS WERE 120 GRAINS BY VOLUME.
 
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Most stuff will interchange but tolerances over the years can vary. Never had a issue swapping triggers. Bolt fits. Stock probably needs inletting around the front half of the recoil lug.
Notice how the lug is forked? Its wider and longer than an Extreme lug.
X2bpubu.jpg


Breach plug wont swap. Mountaineer plug is longer. Lehigh's Mountaineer plug is $24.45 shipped to your door. You will need either a bare primer bolt body or a Lehigh red jacket adapter for your bolt. The adapter is $14.50 so if you go that route buy it with the plug. Good idea to get 2 actually in case you lose one. The other option is the bare primer bolt body from Sportsmans for $85 shipped. Your bolt internals will swap right into it.

Thanks for the info. For now I'll see how it shoots. But this gives me some options to think about. At some point I do want to get a faster twist 45 than my 1:30.
 
Ive never had luck getting monolithic to shoot sabotless with BH209. Even SSTs can be aggravating. I had to size the 225gr FTX so tight i was worried about having to swab occasionally.

If i get up the courage im gunna give one a whack to see if it starts. If it does i will pre-engrave a few for its first test fire. Just pop them in and backout. Marked with a sharpee to line them up the same way later.

The interesting part is these are supposed to be .451 230gr Lehigh CF bullets. My BEs are .4505 or they were when i measure them long ago. Need to get out my digital caliper again and check.
 
Well they are both .4505 with light pressure and .451 with a little less. Knurling is about .454 so that is a bit large. I will have to dig out the micrometer if i want to rule out a digital error.
 
Fix #2 because i really like the NFPJ adapter as far as ease of loading the 209 primer. Im starting to lean towards hotter primers for hunting but that is still up in the air. So i did this with a Fed209A. Same thing worked with 1 less shim and a Win209.

Plug is 20 thousandths shorter. Plug had 15 thousandths worth of shims in it. So actually this can probably be done with a slightly longer plug too and no shims.
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Fed209A looks great but i did not measure crush. I did it by feel with a bare bolt body. If the bolt body falls all the way into battery on its own its too loose. If it stops short and you have to push it down its crushing the primer.
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Fix #2 because i really like the NFPJ adapter as far as ease of loading the 209 primer. Im starting to lean towards hotter primers for hunting but that is still up in the air. So i did this with a Fed209A. Same thing worked with 1 less shim and a Win209.

Plug is 20 thousandths shorter. Plug had 15 thousandths worth of shims in it. So actually this can probably be done with a slightly longer plug too and no shims.
bFwLELm.jpg


Fed209A looks great but i did not measure crush. I did it by feel with a bare bolt body. If the bolt body falls all the way into battery on its own its too loose. If it stops short and you have to push it down its crushing the primer.
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The masters hand . Love what youre shareing !!!!!
 
Knight offers the new style Extreme bolt body too. It just does not have the knurled knob or jeweling. Its about $61.50 plus shipping. Its not listed on the website. You have to call and ask for Steven. Tell him what you want to do. Or you can buy the whole dealo from Sportsmans for $129 shipped and its machined to fit older Knights. It comes with a complete Extreme bolt, FPJ plug and retaining screw.

I told him i already had a bare primer plug and just wanted to upgrade to the new style bolt body. He said no problem and got me a price for just the body.

Possible fix #3
It looks like my first guess was sorta right but the plug clearly had to be hitting the face of the adapter. Not the primer stack nose on the inner shelf. So the question is.....If i take 20 thousands off the face of the adapter will the nose still hit the inner shelf.

Its clearly impossible for it to be hitting the inner shelf YET. There is still a gap with the FPJ adapter resting on the plugs bolt. So it must be hitting the nut first but im guessing a little bit will need to be removed from both spots with my parts.
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While tinkering today i grabbed my Lee .451 die and a couple bullets. Need to try more bullets but as total luck would have it.............

A Speer run through the die 3 times loads and goes down the tube. Its snug but i think its gunna work. So my guess now is the bore is more like .4507-.4508. Bullet is just a tad tighter at the muzzle then very smooth/even past that. This is gunna rock sabotless if thats the case. Right now i have a fair amount of primer only fouling in the bore from testing primer fit.

300gr XTP also. 1 pass through the die is too tight but 3 passes and it goes down. Now i need to dig up some bullets that are .451 without sizing.
 
Looking forward to your range reports. I almost can't take it anymore and have been close to ordering a fast twist 45 barrel.

Are the outside barrel dimensions the same as a 50 cal. Mountaineer?
 

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