Rebarrel knight mk 85

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flounder

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I know there is a wealth of knowledge in this sub-forum so I thought I would see what you thought of this idea. I have quite a few of the older mk 85s that have barrels that are threaded into the receiver. I would like to change one out with a fast twist 45 caliber bull barrel 1" in diameter. I was thinking if I removed the old one first then I could sent it to whoever I buy a new barrel from so they could thread it and do whatever machining is necessary so it would fit the action just like the old one did.
I would like to do as much of the work myself as I possibly can. I have an extra laminated stock that I would remove enough stock from so it would accept the larger bull barrel.
Any suggestions would sure be appreciated. I am just gathering information for now as this would be a winter project.
Thanks a lot,
Art
 

52Bore

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Art:
Aren't these the plunger style? If so and you want to use a stout load, you will not be able to keep is sealed off - accuracy loss with MV inconsistency. Probably OK for hunting, but x's at 200+ will be difficult.
You can copy the existing OD threads and ID dimensions for the breech plug. Should be basic machining on straight round bbl. Keep in mind, current Knights are 1.080" diameter at the receiver - your weak point will be between the OD threads and breech plug threads at the end of the action face.
FYI: I think a Rem 700 ML action is much larger at 1.350".
Keep us posted..

Are you planning BP or SML?
What load are you thinking?
 

flounder

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52Bore, I shoot Black Powder only and homecast lead conicals. Maybe another action would be better. The thing that got me started is that I always wanted an mk 85 in 45 caliber but they are very rare so the thought occurred to me that I could just put a different barrel on an mk 85 receiver with a fast twist for large lead. I am just becoming more informed at this point. Thanks for your input, I appreciate it.
Art
 

bestill

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You could pull this conversion off but if mk85 action is 1.000 going to get very critical during design process. If you stay with#11 ignition you would need to make a custom9/16-18 breech plug and extend front sealing surface out past threaded shoulder of Barrel tenor to keep barrel integrity.
I tend to agree with52bore . I would tend to go after a 1-20 twist disc45 then convert to a bare primer system and use a mountaineer bolt handle. This system headspaced properly are extremely accurate and clean .

But the mk85 conversion could be done just going to take some design work and time .
 

WV Hunter

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I certainly can't give you any technical advice, but I've always looked out for a Mk in .45 too. Just something I've wanted. BUT...I've decided its probably never gonna happen, they just aren't around much. I wonder how many were actually sold. Thing is, I almost ordered one back when I got my original MK...but last minuted decided on a .50 :d'oh!:

Assuming you are looking to just use it for a nice hunting rifle, it might be worth doing. At least you have the option, none of my MK's have threaded barrels. Would be cool to do, doesn't sound like it would break the bank. And you'd have one of a kind :mrgreen:
 

flounder

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One thing I should point out is that I am not trying to create a 500 yard gun here. I would like an accurate gun like my other mk 85s have proven to be but I have no illusions of creating the kind of rifle you all use in long range competitions. I put the post in this subforum because I respect the knowledge I have witnessed from some of the posters here.
Here is what I am trying to wrap my brain around. The original barrel is threaded into the receiver so I have a hard time understanding why a replacement barrel threaded into the receiver the same way creates design difficulties. I would think if the replacement is a smaller caliber that would actually mean there is less weakness than the original.
The original barrel measures .960 where it meets the receiver so if a .960 bull barrel would create less difficulty than a 1 inch bull barrel that would be fine.
Thanks,
Art
 

52Bore

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You are or are not trying to create a 500yd rifle? I think you might have omitted a word?
Regardless, if you've shot the same weight bullet and load in your rifle/action as you intend to shoot in the same action with this new 45 bbl - then I agree with you as there is no reason it should not safely work.
You probably know you might end up with more cost in this than a used/new 45 1:20.
 

flounder

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Sorry you are right I omitted a word, I fixed it. Yes, the cost, there is always that factor. That's why I said earlier I am in the information gathering phase.
First I wanted to see how feasible it was and then of course I would have to have some idea what another barrel and the labor would cost. There might very well be a good reason why no one has done this with an mk 85.
Thanks for the response.
I do already have a couple 1 in 20 .451 Whites so I have something to play with anyway. :D
Art
 

bestill

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Here's a ideal.
Custom barrel brux or Douglas etc. $400-$450
Barrel thread and headspace for factory breech$225
 

flounder

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Thanks bestill and 52Bore,
It's not sounding too cost effective.
Back to the old drawing board.
Art
 
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