1894 Marlin caliber conversion

[clodbuster]

I just love the 256 WinMag.  but my Marlin model 62 is a POS as a working rifle.  What da ya think of converting a Marlin 1894 in 357 mag to 256 winmag?  Could the barrel be relined or better to go with a new barrel?  What else would be required?

[gunnut69]

Should work just fine.  I'd go with a re-barrel though.  There's no worry about the barrel markings..

[Chuck from arkansaw]

You are in luck, all you need is a 1894 in .357 and a barrel in 25-20 from gunparts.  Ream the barrel to .256 and install.  You have a brand new .256 model 1894.  Yes it has already been done.

[clodbuster]

Chuck  You make this job sound so easy that maybe you've done it already?  If so how do you like it?  Where did you get the barrel?  Thanks for the info and Happy New Year    

[Prince of Wales]

I like the idea of this conversion a lot. Recently had my 62 Marlin converted from 256 to 357 Mag not because I did`nt like the 256 but because I wanted to hand the rifle down to grandkids. I did not want them to have a gun for which they HAD to reload. The 357 is not going to be obsolete within their lifetime I think its safe to say.
 The 62  is in excellent condition and I really like the way it shoots now in 357 BUT I still like the 256.
 Here is what occurs to be about the conversion. First I know a lot of the 256s velocity and accuracy that make it such a good round are attributes of the 24" Micro-Groove barrel. And secondly without the clip the bullet selection is going to be narrowed to round and flat point bullets. Putting that combination together how much would be lost in using the 256 in a carbine? Best of luck. POW

[gunnut69]

The only reason for round/flat point bullets in a tube mag is posibility of recoil causing a chain reaction in the magazine.  With the tiny recoil impulse of the 256 I seriously doubt there would be any danger of that.  Still the advatage of the pointed bullet is in long range applications.  Not exactly the 256's forte..  so little would be lost by restricting oneself to round nosed bullets.

[Prince of Wales]

Chuck can one take this advise one step further and assume that any 25/20 is a candidate for 256 conversion with the 256 reamer applied? Is anyone currently producing a 25/20 carbine? Best of luck. POW

[gunnut69]

The 25/20's have a different case head than the 256.  The 256 is much larger, based on the 357.  The 25-20 was suggested as a simple way to get a 25 caliber bore in a barrel made for the action in question.  The 25-20 and the 32-20 have the same casehead as does the 218 Bee.  The 357 caliber is popular because of cowboy shooting.  A Marlin or anything in 357 could easily be rebarreled with a 25 caliber barrel and reamed for a 256..

[clodbuster]

Gunnut69   the 25-20 case is about 50 thousandths longer than .256 W-M  Does this turn into freebore or does the smith deepen the new chamber and shorten the barrel base?  Or is it just magic?

[gunnut69]

Fifty thousandths is an insignificant amount.  The slight difference in length won't make a differenct but the difference in neck diameter may leave a ridge in the last .0050 inch that while not dangerous would be a cosmetic problem..  It may also lead to a bit early case failure.  I shouldn't think is a real problem though..  and quite probably would polish out..  More problematic is the .0185 inch difference in the throat diameter with the 25-20 being that much larger.  This would in effect give us an oversized throat in the 256.  That is of course if the marlin barrel is held to those tolerances.  There is also a major difference in the lead angles.  The 25-20 is a much older round and as such the design is altered, though not necessarily to the detriment of the alteration..  I still hold this to be a doable rechamber and a useful one at that...  
Jerry

[Prince of Wales]

gunnut69 wrote " I still hold this to be a doable conversion and a useful one at that".
 Gunnut69 do you refere to the original question  of clodbuster from Dec. 28 or to my post of Jan. 2? Thanks and best of luck. POW

[gunnut69]

Well POW to both as far as the statement went.  To convert an existing 25-20 chamber to 256 would work and would be quite do doable from the chamber dimension perspective.  Converting a rifle designed for the 25-20 round to feed the 256 may pose extra problems.  Mainly due to the casehead differences.  If the rifle being converted were a single shot the problem would be mild, if a marlin 25-20 were being converted there would be some serious conversion quetions, relating to feeding the 256 case.