Plainsman, I posted the same question awhile back or suggestion rather with the idea in mind of having the same conversion done to a Browning and everyone seemed to agree that the pressures etc. were too far apart to make it a safe or practical conversion. Since most of the serious responses I get here seem to be backed up by research or experience I accepted it and abandoned the idea.
Also, Contenders are often chambered for the .444 so the action doesn't become a deterrent. Plus NEF also chambers the same rifle for higher pressure cartridges than the .44magnum. They just don't offer much of a selection in calibers.
The Browning in question was a Low Wall. It really isn't designed for such long and big bore rounds. They should go into the high wall. Since the NEF is chambered for the .45-70 and many other long bottle necked rounds I certainly doubt the action strength would be a problem as in the LW. If the barrel has sufficient diameter all the way out to where the end of case would be and IF the frame is one that will take the higher pressure bottle neck rifle rounds my guess is it shouldn't be like the TC or the Browning in that respect.
I'd make sure a qualified and respected gunsmith did the work. If they are willing to do it most likely it is because they are sure it will be safe.
i have rechambered 6 of these rifles to 444 and all are shooting fine. all are under 1.5 inches at 100 yards and at least three of them are over 500 rounds with no problems. They are putting the 450marlin round and the 30-06 in front of the sb2 so pressures are not a problem. the only extra work I discovered was neccessary was to put a slightly stronger spring in the for the locking lug. I also did some light stoning on the lock to get more engagment, you would be surprised how little engagment there is on some of these rifles out of the factory. The recoil is a bit on the aggressive side but with the addition of a good muzzle brake mine has less recoil than my '94 30-30 lever gun. Hope this is of some help.
Before you rechamber from .44 mag to .444 marlin go to http://members.tripod.com and see what happened to a guy who fired a Contender barrel that had been rechambered from .44 mag to .444 marlin. Very ugly. Blew up on the 38th round at thte breach end. The barrel burst outward like the proverbial banana peel. Pretty nasty.
I am pleased to hear that the gentleman with the Contender was able to make a good recovery. In defense of the NEF SB2 44 to 444 Marlin conversion, This rifle is available from the factory in 30-06, 270, 450 Marlin and 25-06. The 30-06 and it's 2 variants are all in the the 50-54,000 CUP this is in excess of 60,000 PSI, The 450 Marlin is in the 40,000 PSI range and exhibits more felt recoil than the bottle necks. The 444 Marlin is in the 44,000 CUP range well below the bottle necks, and less felt recoil than the 450. The 44 magnum approaches the 40,000 CUP range. I am not aware that the Contender was available in anything that approached these numbers thus the birth of the Encore for those who wanted more to hang on to. This brute has been chambered for rounds that personally I feel have no place in a handgun including the awsome 458 Lott. But, to each thier own this is America. I feel that NEF/H&R are missing the boat by not offering this caliber to the sportsmen and women who would enjoy it. All recievers have thier stated pressure limits and should never be exceeded, if in doubt DON'T! I do however enjoy shooting my NEF in 444 and the accuracy is great, 1.5" and under at 100 yards. Enough said, thanks to those who are listening.
The pressure range is what makes these guns different indeed! I had a Contender and it's only meant for older, lighter pressure cartridges. But shooting anything heavier than a .44mag in a Contender was not for me at all. Even the .44 with a 10" barrel was brutal for recoil!
I can shoot my 4" barrel Redhawk with the same loads much better and notice less recoil!
Per Scott Tanner on the NEF Singleshot site on Yahoo, he had a .44 mag NEF converted to .444 Marlin by Revelation Arms in Oregon. I understand he has had this done on several barels and they work very well for him.
'Bout the only thing I'd care to add, outside of the fact that those who think the 444 is unsafe in a modern SB2, but just perfect in that real strong Marlin lever need a reality check, is that I'd go with one of the "Modern" SB2's with the
NN,NP,NR,NS etc serial number prefixs. The 44 Mag was chambered in all sorts of different NEF/H&R receivers, some of which won't handle 444 pressures for a real long time.
Just think about it, all the .44 caliber bullets on the market today are made for the handgun not the rifle. And these bullets do not perform well on game the way a rifle bullet does. The bullet manufacturers are not up on the times in this aspect! I have seen a .444 Marlin bullet make a mess out of a 245 pound Russian boar! A .44 hole on the entry and a hole the size of a soft ball on the other. It is not good good performance for a bullet of a rifle.
What rock have you been living under for the last dozen years or so!?
The bullet companies have been making extremely GOOD bullets for both the handguns AND rifles, esp. the .444 Marlins! Beartooth bullets even makes a 405 GRAINER specifically for the .444 Marlin and Ruger Redhawks!
I think you need to take a look around at what is offered these days. Between well built jacketed bullets like the XTP and exceptional hardcast like Beartooth, we have a very NICE selection of .429-.430" bullets to choose from. I'd even be safe to say they will work in a variety of loads as well, from specials down around 700fps to the .444Marlin at 2,000fps.
Not to mention, since when is an exit hole the size of a softball a "bad" thing!? :-D
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