manureman Posted September 8, 2006 Report Share Posted September 8, 2006 I've got a young fella that helps me around the farm some,he's a preacher( I won't hold that against him)with 3 kids in grade school and moneys pretty tight for him.When he helps me I can't hardly get him to take any pay,partly I figure because I let him hunt on me but mostly just because were friends and he's that kind of guy,but it still don't suit me much.Anyway this boy has got the hots for a 7mm Rem Mag.I'd like to try and put him one together to repay him for all his help but I've had a bear of a time getting one or two standard calibers to feed in the past and I figure a belted mag would be worse.I'm no smith or even half arsed machinest but I,ve got a Smithy that I figure I could open the bolt up on and I figure I could rework the magwell( taper and length) With my smithy ,mig welder and hand tools but the follower and the rails kind of bugger me.I can remember seeing followers advertised for this conversion but I've not noticed them for a while. As far as opening up the reciever the only thing I've got to go by is Walsh's book,it's around here someplace and has a blueprint of a mag. reciever but I don't know that it's right or even close for that matter.Any words of wisdom other than don't or just cut your throat now and get it over with? Thanks Jim Link to comment Share on other sites More sharing options...
z1r Posted September 8, 2006 Report Share Posted September 8, 2006 Well, I can certainly understand wanting to build him what he wants but as a practical matter, maybe something you are reasonably sure you can build might be more practical. I think the .280 Rem is a dandy. Not really all that far behind the 7mm mag, cheaper to feed, and easier on the shoulder. So too is the 7x57 Now, we all know what that advice is worth so: To build a mag, open the bolt face. Search the archeives where I and others posted pics of the carbide tipped lathe bit used for the purpose. Let me know if you can't find it. Alter your extractor. As for opening rails, I found Walsh's instructions to be near worthless. Instead, study how the factory round travels out of the magazine and into the chamber. Note where the shoulder bumps the little "ramp" on the rail and starts to jut the nose out. Then try to apply that relationship to the dimensions of the Magnum cartridge when altering rails. The feedrails by the way are the underside just above where the magazine meets the receiver. Most people think it is the top where the bolt lugs slide along. No. But, that area will need to be widened up front near the feedramp to allow the fatter cartrdige to emerge from the magazine. Feedramp will need to be widened and blended with the altered passageway yto channel the nose of the cartridge into the chamber. Magazine. You are attempting the correct way it is also the hard way. Oddly, the Charles Daly and related (Mk X) do not have the proper magazine geometry but do feed reasonably well. In other words, do not waste your money on the "Magnum" bottom metal being sold on eBay and else where. It is the same as the standard bottom metal, exactly. If you want hinged bottom metal don't pay the premium most seelers are asking for the magnum stuff, get the standard instead or just alter your military piece. I've seen buddies employ the issue magazine only lengthend but you will have to adjust your rails accordingly. So, decided beforehand on which magazine you want to use before turning your attention to the rails. Follower, use the one you have. Go slow, study how the issue cartridge feeds, go slow, study some more, go slow. And you will be fine. Link to comment Share on other sites More sharing options...
Doble Troble Posted September 8, 2006 Report Share Posted September 8, 2006 Jim, My elitist streak is telling me to try to convince him that he wants a 7 x 57. You're right not to do that right away as he'll learn it himself as he starts thinking about rifle building which I suspect you're about to get him to start doing. But a 7 mm Mag really does look good on paper. I haven't built a standard (what used to be "short") magnum on a Mauser. I have done a couple based on the 376 Steyr which is a similar case head. You'll have to open up the bolt face which only takes a few min if you have a mill - use a carbide tool as them Mauser bolts are hard (Z taught me this - thanks, Z!). If you don't have the mill I don't think it would be too difficult to farm-out if you have a friendly machine shop in the area. Post again if you need specs. I bet you can get it done nicely on the Smithy. I am a Bubba and so immediately think that if someone else has done something that I can also easily do it. So I don't think that it will be a big deal to modify feed ramps to accept a 7 mm Mag. But I haven't done it either. I hope others will offer you better and straight-forward advice. I can offer this bit of wisdom that I'm sure you already know: measure twice, cut once. Jason gave me some dimensions for the 8 x 68 (I wound-up doing an 8 mm Steyr which for reasons I don't understand fed fine without modification) and he may have studied up on the 7 mm Mag also - he's studied Mauser's principles and equations and may have dimensions, he'll have good input for sure. I bet that you can do a really good job - and its going to be really well appreciated. EDIT: While I was busy typing away Z posted really good advice above! Link to comment Share on other sites More sharing options...
manureman Posted September 10, 2006 Author Report Share Posted September 10, 2006 Z,DT thanks for your replys and I appreciate them and I'm sorry to be slow in thanking you for them but just as I was about to the other night the doorbell rang and things turned into a running screaming cluster fornication for a couple days,someone ran through not just my fence but also my nieghbors and left without telling anyone and our cattle had gotten out ,gotten together,got on each other and also gotten on a big tract of public hunting ground...what a rodeo.First my search turned up a link to the piece about opening the bolt face as I remember reading it but I couldn't get the link to come up, but my plan is to order a bolt face opening bit from Brownells(you guys got me thinking I can do this) and practice on a few junkers by screwing in a heat sink ,chucking that in the lathe and using a steady rest out near as I can the other end.For the extractor,I'm undecided as to trying to modify what I have or ordering a magnum one and starting there,I'm leaning toward ordering one as I figure that might be the simplest,and best on this first go around .For the bottom metal I think after readin' what Z had to say I'll just lengthen the military magwell,rather then choping one all to pieces.For the follower Z says use what I got so thats what I'll do.Now on the rails I was really surprised when I took a 7mag round and placed it into the rails on a stripped reciever and slid it forward by hand studyin' it like told.First thing I noticed was the rim didn't cause it to lay at the sharp angle I expected,the 8MM has alot more taper to the case body than the mag does so the rim on the mag round actually makes it lay alot closer to how the 8MM does than I expected,and I'm sure it's going to be worse than it looks but at first glance the big mag looks to be a better fit than say a 22-250 and simular length stuff that has given me fits in the past.Z what do you recomend using to open the rails with?Thanks Jim. Link to comment Share on other sites More sharing options...
manureman Posted September 10, 2006 Author Report Share Posted September 10, 2006 Can't get my edit to work for some reason but I was wondering about dummie rounds.When I make mine up I use a piece of unprimed full length resized brass and seat a sitzer bullet out to the max.oal ,is this right? Thanks again , Jim Link to comment Share on other sites More sharing options...
donmarkey Posted September 10, 2006 Report Share Posted September 10, 2006 I never had any luck with the brownells bit unless I annealled the bolt first. Then a homemade hss bit will work also. Modifying a extractor isn't hard if you take your time and check the fit often. Even new ones sometimes need to be fit. -Don Link to comment Share on other sites More sharing options...
manureman Posted September 10, 2006 Author Report Share Posted September 10, 2006 Thanks for the heads up but crap thats not what I wanted to hear!Are you talking about the carbide tipped one ? Jim Link to comment Share on other sites More sharing options...
donmarkey Posted September 10, 2006 Report Share Posted September 10, 2006 Thanks for the heads up but crap thats not what I wanted to hear!Are you talking about the carbide tipped one ? Jim Yep, I just ordered one of midway's carbide burrs. And way going to give that a try. Those bolts are hard! -Don Link to comment Share on other sites More sharing options...
manureman Posted September 10, 2006 Author Report Share Posted September 10, 2006 *&$#@ !!! Well time to go ride a combine scratch my butt and re think. Jim Link to comment Share on other sites More sharing options...
donmarkey Posted September 10, 2006 Report Share Posted September 10, 2006 *&$#@ !!! Well time to go ride a combine scratch my butt and re think. Jim Getting it reharded is the way to go, exspecailly that it's a mag and you don't really know if it was hardened properly to begin with. Then you can weld and machine all you want without worrying. -Don Link to comment Share on other sites More sharing options...
z1r Posted September 10, 2006 Report Share Posted September 10, 2006 HSS won't work without annealing like Don said. I just grind my own Carbide tipped bit. I got this one at HF and modified it to work. It cuts well. Opeing up the rails with a ball end mill is best. then do whatever other work is required with a file(s). Link to comment Share on other sites More sharing options...
manureman Posted September 11, 2006 Author Report Share Posted September 11, 2006 Thanks again guys! Jim Link to comment Share on other sites More sharing options...
donmarkey Posted September 11, 2006 Report Share Posted September 11, 2006 Then midway bit worked great! It's meant to be used with their truing kit, but I just chucked it up in the tailstock. -Don Link to comment Share on other sites More sharing options...
manureman Posted September 12, 2006 Author Report Share Posted September 12, 2006 Thanks for the update Don,I'll have to order me one. Jim Link to comment Share on other sites More sharing options...
Recommended Posts