Whats involved in rechambering a milsurp rifle for BIG cartridges?

simko

simko

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Hi everyone, im wondering a few things as normal:


whats involved in takeing a bolt action milsurp (p14, p17, k98) or anyother VERY strong actioned gun and rechambering it for a bigger caliber?


i originally wanted to rechamber a mauser to something like .416 Rigby, or .458 lott, but then kevin brought up the p14 in a .405 winchester

i wanted to know, say i boguht a p14 in .303 right now, what would i have to do to rechamber it to .405 winch?


i look forward to your comments and suggestions

thanks in advance



aaron
 
Well one guy on the site has a P14 in .505 Gibbs, I've shot one in .375 Weatherby, someone will be along shortly to tell you all the dirty little details...
 
Like everything else, there an easy way and a not so easy way. Real easy- find a bubbaed P14 and rechamber to 303 Epps or 303 Winchester magnum- this will allow you to use the existing barrel. Something like a 458 Win or 458 Lott can be done with a Shaw barrel for about $200 US or so. For a realistic step up, the 500 A Square is probably the best (460 Weatherby necked to 50 and blown out). PAC NOR has P14 threaded barrels. There are two problems- getting the rifle to feed reliably and getting the barrels to Canada. I think that Ron Smith in Alberta makes barrels and chambers for some big boys (577 Nyati) but I am unsure of prices. Another approach is to use the Ruger #1 single shot- PAC NOR will thread and chamber just about anything to this action.
 
Bevan King is set up to contour and rebarrel your P14. so are many other smiths. finding a barrel blank is a source for scrounging, but it's not that hard, any blank will do, just get it threaded for the action. many .416 rigby, .458 Lott's, 500 A-Sq, all the way up to n85 Nyati have been done on these actions (if you want a Nyati, talk to Bevan King, has barrels and reamers)

the FIRST step is to determine the make. ERA stamped on the reciver? toss it in the dumbster unless you want to build a non-magnum.

next step is a magnaflux. this can be done at some machine shops, avaition repair, engine rebuilders etc. it will test for cracks, flaws, etc.

any good gunsmith should be able to turn your "passed" P14/17 action into a big thumper. Bell & Carlson and Boyds makes stocks inletted for these rifles. I';m sanding down a very ###y Black Laminate JRS Classic for a p14 action at the moment, gonna be very nice when it;s done.


Good luck!
 
"...303 Winchester magnum..." A what? There's no such thing as a 303 Winchester magnum.
"...rechamber a mauser..." New barrel and alter the bolt and mag, not just rechamber. Ditto for the .405.
 
sunray said:
"...303 Winchester magnum..." A what? There's no such thing as a 303 Winchester magnum.
"...rechamber a mauser..." New barrel and alter the bolt and mag, not just rechamber. Ditto for the .405.
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Well, sort of. There are more then a few P14's running around that have been rechambered to a 300 Win Mag, but with the 311-312 bore of the original 303 still there, hence the "303 Win Mag". As for the Mauser, if it's an 8mm you can rechamber for the 8mm PMM (Poor Man's Magnum, 338 Win Mag case necked down to 8mm). Still need mag box, bolt face, and feed rail work tho'. - dan
 
Re: 303 Winchester Magnum
Sunray has it right. There is a long standing thread GunNutz thread on this topic. Simply rechamber a P14 in 303 to 300 Winchester Mag and with reload 303 bullets using a 300 Winchester die. I have not done it, but a few on this site have. I know the bolt face is correct.
 
rechambering

Have one 308 Norma built on an enfield use 311 bullets works just fine load with 308 bullets and they hit the paper tumbling like a bugger. Kicks like a mule on her last legs finally had to get a decelerater pad put on it. Still has kick but liveable.Thanks Ken
 
Niether the .416 Rigby, nor the .458 Lott would be advisable in a K98. The cartridges are too long and require removal of metal in important areas. I don't think a .416 Rigby case size would be doable at any rate.
 
Both the 458 Lott and the 416 Rigby have been chanbered in 98 Mausers before, Selby's famous 416 was built on a 98 for example. The first 338-378 Wby I ever fired was built on a commercial Mauser action (98 sized). Someone with the talent for it can open up the rear of the action, and perform the rail mods, check the hardening, reharden if required etc. Anything is possible, it's just no longer economically good sense, that kind of work requires talent, money and time. FWIW - dan
 
sunray said:
"...303 Winchester magnum..." A what? There's no such thing as a 303 Winchester magnum.
"...rechamber a mauser..." New barrel and alter the bolt and mag, not just rechamber. Ditto for the .405.
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actually with the .405 Win you don't have to alter the bolt face or the mag if built on a P14, thats why i suggested it. can also use a No.4 for this particular conversion. and it's probably the cheapest and easiest to get loads and components for. douglas barrels makes a .405 barrel and will cut, thread, chamber and contour to your specs all for under $500 US to your door, including government ass rape import fees.
 
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dan belisle said:
Both the 458 Lott and the 416 Rigby have been chanbered in 98 Mausers before, Selby's famous 416 was built on a 98 for example. The first 338-378 Wby I ever fired was built on a commercial Mauser action (98 sized). Someone with the talent for it can open up the rear of the action, and perform the rail mods, check the hardening, reharden if required etc. Anything is possible, it's just no longer economically good sense, that kind of work requires talent, money and time. FWIW - dan
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Are you sure you are not talking about a Magnum Mauser (ie. Brevex or similar)? Modifying the feed ramp to accept even a .300 H&H or .375 H&H requires removal of material from behind the botom reciever lug, making that area weaker. Plus the Rigby/Wby (.378 based) have .582" - .603" diameter rims. That means having a bolt centering radius of between .294" and .3045", the factory design for .473" designs is .239". Can you safely open the bolt face that much?
 
As far as easy, inexpensive improvements for common milsurps, these aren't "Big" cartridges bore-wise, but are a big increase over the original cartridge.

1 - M1917 Enfield (aka P17) - rechamber to 300 Win Mag. Requires rechambering, an unmodified bolt from a P14 and some "tuning" of feed rails and ramp, and the mag box.

2 - P14 Enfield - rechamber to "303 Win Mag". Rechamber with a 300 Win Mag reamer, uses the original unmodified bolt, and some "tuning" of feed rails and ramp, and the mag box. Use a 300 Win Mag die set with 0.311" bullets. Outside neck turning of the brass is a must.

3 - any 8mm Mauser - rechamber to 8mm/06 or 8mm/06 AI. Dies and reamers are a little easier to get for the former, and not much more expensive than the 8mm Mauser dies.

Once upon a time (one of two Gunnutz "crashes" ago), this was all discussed. It's a bloody shame that all that info, wisdom, and contributing members were lost. Looking at our sight today, one would think Gunnutz has only existed a few months. Hopefully the re-worked system with sponsors supporting it will ensure that won't happen again.
 
By all accounts that I have read, the Selby .416 Rigby was indeed built on a standard Mauser 98 action.

http://forums.accuratereloading.com/groupee/forums/a/tpc/f/1411043/m/949101013/r/949101013#949101013

The diameter of a 98 bolt is .700". If one were to open the face to .582", one would still be left with a ridge of metal of approx .059"(actually a bit less to provide wriggle room). That's not much, but obviously it's enough. The purpose of this ridge is to provide support to the case when the case is held in place by the extractor. The ridge isn't a safety feature so much as an essential part of the controlled round feeding system.

As mentioned above, the correct way to modify the 98 to accept a longer cartridge is to open the magazine to the rear so that as little metal as possible is removed from behind the lower lug.

It is worth mentioning that the Interarm Mark 10's(and I assume the Whitworths) that are chambered for the .375 H&H Mag are entirely opened up at the front. As long as we load to traditional pressure levels and don't try to hot-rod the load, this set-up is fine.
 
Mauser98 said:
The diameter of a 98 bolt is .700". If one were to open the face to .582", one would still be left with a ridge of metal of approx .059"(actually a bit less to provide wriggle room). That's not much, but obviously it's enough. The purpose of this ridge is to provide support to the case when the case is held in place by the extractor. The ridge isn't a safety feature so much as an essential part of the controlled round feeding system.

As mentioned above, the correct way to modify the 98 to accept a longer cartridge is to open the magazine to the rear so that as little metal as possible is removed from behind the lower lug.
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I should clarify what I meant about "safely"...I mean to have reliable exctraction, which, if used on game the caliber is intended for is directly related to safety. Regarding opening the magazine to the rear: The bolt only goes so far back, how does opening the magazine to the rear help? I would assume that the rim of the shell would be too far back for it to be picked up. Does anyone have diagrams of this modification?
 
1899 said:
I should clarify what I meant about "safely"...I mean to have reliable exctraction, which, if used on game the caliber is intended for is directly related to safety.
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Point taken and agreed with

Regarding opening the magazine to the rear: The bolt only goes so far back, how does opening the magazine to the rear help? I would assume that the rim of the shell would be too far back for it to be picked up. Does anyone have diagrams of this modification?
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From what I understand, this modification requires that the bolt stop and the ejector also be modified so that the bolt will move further to the rear and the case will eject properly. Apparently, up to .100" can be gained with this mod.

Part of the process for lengthening the mag box is to thin the front and rear ends by filing or milling. One can pick up to .125".

I have in my shop a Columbian Mauser(FN contract) that is chambered for the .30-06. The mag box on that rifle is 3.41" long. If I were to open to the rear and thin the end walls I would end up with a box approx 3.635" long which is still a bit short so the front of the box would still have to be moved ahead a bit.

Of course, even if the box were long enough, the big, fat round still wouldn't feed. The rails and ramp would need a lot of work and even then then there would still be problems because the mag box wouldn't be wide enough. That is, the stacking angle would be so extreme that when the bolt was opened on a full mag, the rounds in the mag would probably puke out of the box.

As Dan Belisle said
Anything is possible, it's just no longer economically good sense, that kind of work requires talent, money and time
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I had a Parker Hale 30-06 that I Had bevin King rebarrel to a 458 Ackley which is like an improved version of the 458 Lott.It fed and funtioned perfect.There is no problems doing a 98,to get the extra length he modified the feed ram at the front.
 
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