SMLE #4 mk1 conversion to 444 marlin?

Discussion in 'Rifle Country' started by adcoch1, Apr 26, 2021.

  1. adcoch1

    adcoch1 Member

    Joined:
    Oct 2, 2015
    Messages:
    2,879
    Location:
    Centralia Washington
    I picked up a project smle#4 mk1, and while fiddling around with it I realized the bolt head will fit a 444 marlin brass perfectly. And it appears it could be rebored to clean up the chamber too.

    So, anybody ever rebored or rebarreled an SMLE to 444 marlin? Maybe I should call JES reboring?
     
  2. Alaskan Ironworker

    Alaskan Ironworker Member

    Joined:
    Feb 5, 2018
    Messages:
    878
    Location:
    Wasilla
    Sounds like you’re onto something cool there.
     
    LoonWulf likes this.
  3. adcoch1

    adcoch1 Member

    Joined:
    Oct 2, 2015
    Messages:
    2,879
    Location:
    Centralia Washington
    If I remember correctly the pressure is about the same for 303 and 444 marlin, and the bolt head is the same size. My magazine for this rifle is a reproduction anyway so mods aren't a huge deal, and its already been sporterized halfway by Bubba, so why not?
     
  4. Ugly Sauce

    Ugly Sauce Member

    Joined:
    Oct 26, 2020
    Messages:
    1,026
    I believe that has been done. I don't think it's a difficult conversion. I know they convert the 91/30 to .45-70, SMLE to .444 should be just as easy or easier. I don't think the mag would hold many .444's, but not being a high-capacity guy, I'd be happy with with a two or three shot magazine, which I think would be easy to make out of the SMLE mag.

    All things considered, I think you'll wind up re-barreling it. That might be more cost effective. And SMLE barrels are pretty skinny.
     
  5. Dave DeLaurant

    Dave DeLaurant Member

    Joined:
    Nov 12, 2018
    Messages:
    1,476
    Location:
    People's Republic of California, Central Valley
    I thought hard about doing a .303-to-.444 conversion for a salvage project on a .303 Martini-Enfield with a shot-out bore. In the end I went with .44 Magnum (new barrel and forend), but the gunsmith I worked with felt that either chambering would have been equally suitable.

    Marteenie.jpg

    One minor consideration: the .303 cartridge was made with a beveled rim to help avoid rimjams. Assuming feed is otherwise smooth, you'll want to load the .444 cartridges in the magazine a bit more carefully to avoid this:

     
    Last edited: Apr 27, 2021
  6. adcoch1

    adcoch1 Member

    Joined:
    Oct 2, 2015
    Messages:
    2,879
    Location:
    Centralia Washington
    Dave, that little martini is a sweet carbine, if you ever decide to sell...
    I would probably make a single stack mag for this thing if I convert it, the mag body tapers toward the front too much to run big fat bullets very easy. Or maybe steal the 410 Enfield mag design.
     
    LoonWulf, gobsauce and Dave DeLaurant like this.
  7. AlexanderA
    • Contributing Member

    AlexanderA Member

    Joined:
    Feb 27, 2011
    Messages:
    7,768
    Location:
    Virginia
    The No. 4 barrels are considerably heftier than SMLE barrels. (The No. 4 is not technically an SMLE.)
     
    LoonWulf, adcoch1 and Ugly Sauce like this.
  8. Ugly Sauce

    Ugly Sauce Member

    Joined:
    Oct 26, 2020
    Messages:
    1,026
    True, a No.4 is a heavier barrel. What would the wall thickness be after boring?
     
    LoonWulf likes this.
  9. MachIVshooter

    MachIVshooter Member

    Joined:
    Aug 11, 2005
    Messages:
    17,001
    Location:
    Elbert County, CO
    That would be a neat conversion! And, unlike a previous discussion of belted magnums in a Garand, this would be perfectly safe with the .026" smaller rim and slightly lower chamber pressure of the .444.

    Will probably still extract fine, .303 has a ridiculous step from base to rim compared to most rimmed rounds. I imagine mag capacity will drop to 6 or 7, and it might take some tuning to get reliable feeding, but should be workable without getting too crazy.

    I would personally do it as a rebarrel with a rifled blank.
     
  10. Ugly Sauce

    Ugly Sauce Member

    Joined:
    Oct 26, 2020
    Messages:
    1,026
    To get the magazine almost flush, or flush with the bottom of the receiver/stock, I'd be more than happy with a 3 round magazine capacity, in a caliber such as the .444. I mean, shouldn't take six or seven rounds of .444 to get the job done. But then I hunt mostly with single shots, so magazine capacity doesn't mean that much to me. !! Heck, I'd feel like Rambo on the .50 caliber machine gun if the thing had two in the magazine, and one up the spout.

    I agree, I think re-barreling it would make more sense, I think that a re-bore might result in a very thin barrel that might wander all over the place once the barrel heated up.
     
    LoonWulf and adcoch1 like this.
  11. Oldschool shooter

    Oldschool shooter Member

    Joined:
    Jul 8, 2014
    Messages:
    769
    Location:
    Michigan
    Back in the 90s, Gibbs Rifle Compsny was converting to 45-70. Seems that may be a better choice than the now nearly extinct 444. Not saying the Marlin round was bad, just not as popular and even if you reload, cases and other components may be harder to come by.
     
    LoonWulf likes this.
  12. RCB

    RCB Member

    Joined:
    Sep 22, 2009
    Messages:
    61
    I was just thinking about this myself. The past couple years 444 marlin has been easier to find since they were making 444s again. The leverevolution rounds have reinvigorated many lever rounds as well.
     
    Riomouse911 likes this.
  13. TRX

    TRX Member

    Joined:
    Sep 5, 2008
    Messages:
    1,256
    Location:
    Central Arkansas
    I've done .45-70 using an 1885 Remington-Lee magazine. Works way better than the Navy Arms mags. The SMLE is a descendant of the Remington-Lee; the Lee magazine snaps right in and feeds properly with no fettling needed. You have to fill in the sides of the magwell to keep it from rattling side to side, though.

    .444 Marlin will work with Saiga-410 magazines. Some mags will work perfectly, others will only hold 8 rounds, or have feed issues. You don't know until you try. .405 Winchester will also work through some Saiga mags.

    Your less-traveled option is .375 Flanged Nitro Express 2-1/2", which is basically a blown-out .303 case with a .375 bullet. BSA used to offer that chambering in civilian-market SMLEs. The .375 will work in the 5-round sporter mags; I'm not sure if the 10-round military mags will accept a full 10 rounds. You can get .375 brass, and Kynoch still loads .375 NE, though the new-production stuff is apparently for double rifles and has the bullets set out too far to go into the SMLE magazine.

    A small-bore option is the 6mm Musgrave, which is just another of the many 6mm-.303s, except it's CIP listed and you can buy commercially-loaded Musgrave ammunition. Lee Precision has dies for reloading. You're not going to get benchest accuracy out of an SMLE, but you can tap into the high-quality 6mm barrels and bullets for target shooting, and there's a fairly good selection of 6mm/.243 bullets for hunting.

    There are a bunch of tiny feed ramp cuts in the SMLE receiver to assist the .303 cartridges in their journey to the chamber. In general, they don't affect fatter cartridges one way or another, though there might be differences among SMLEs. The small bolt diameter and low barrel-to-magazine-lip distance do a pretty good job of holding everything in alignment without needing a bunch of fiddling.

    The Enfields use a flat bolt face, a long-travel extractor hook, and a little screw through the left side as an ejector. Generally they need no work whatsoever for any rimmed cartridge, and they'll work well with many rimless ones as wall - 7x57 Mauser was once a popualr conversion in Canada, and of course some rifles were re-arsenaled into 7.62x51 NATO.

    7.62x39 conversions were popular a few years ago, using AK magazines. There have been some homemade .308s, but I think that's asking a lot of an elderly rear-locking action. .300 Savage will generally fit and feed through anything that will run .308, and give you most of the performance with a lot less pressure.
     
  14. adcoch1

    adcoch1 Member

    Joined:
    Oct 2, 2015
    Messages:
    2,879
    Location:
    Centralia Washington
    Well I have a call into JES reboring to see about possible cartridge conversions. My first would be a 444 marlin since I have brass and bullets. We will see if Jesse thinks it's a doable option. I think there should be plenty of meat left in the barrel with a rebore to 430. If not though a 35 cal 303 case would work, or a 375. Kinda excited to be looking at building a custom, thinking about a nice banded front sight and a safari sling. This might be a fun rifle....
     
    LoonWulf likes this.
  15. LoonWulf
    • Contributing Member

    LoonWulf Contributing Member

    Joined:
    Jul 3, 2010
    Messages:
    14,002
    Location:
    Hawaii
    There fixed it for you:p
     
    adcoch1 and Oldschool shooter like this.
  16. eastbank

    eastbank Member

    Joined:
    Jul 30, 2009
    Messages:
    4,521
    why not look at the 375 JDJ, a 444 case necked to 375. i have a TC G2 single shot rifle in it and cases are a one step neck down to 375 with no fire forming needed. i am shooting a 220 hornady at 2300 fps with no signs of pressure. an the mk-4 barrel may be thick enough for a rebore to .375
     

    Attached Files:

    Last edited: May 10, 2021
    adcoch1, Riomouse911 and LoonWulf like this.
  17. Riomouse911

    Riomouse911 Member

    Joined:
    Jun 5, 2013
    Messages:
    5,709
    Location:
    Ca.
    The .375 JDJ was a thumping round in the contender pistol for quite a while, that’s an excellent idea for such a conversion :thumbup:.

    Stay safe.
     
    adcoch1 and LoonWulf like this.
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice