Chick, and for others who care, West of you perhaps 30 miles is the manufactuory of L.E.Wilson -Home of the Wilson Ctg case headspace gage among other neat tools. If you have some sample rounds of .275 Rigby and current foreign and domestic 7 x 57 rounds you can determine the answer to the puzzle rather quickly and not even be required to buy the gage, though all ought to own one if they have the 7 x 57. Now, old "Sam" made more than just 30-06 headspace gages for the US Govt. They at Wilson would of course have them to make certain their ctg gages were on spec. Some of the published dimensions I have encountered over the years seem to have been taken from samples using a brand new Hardware store freebie wooden yard stick and a school supply plastic protractor to determine the shoulder angle. Dave Manley told me that the dimensions on the SAAMI sheet for the 7x57 which I noticed had changed from my reference was based on the submitted latest factory figures for newly made rifles. In this case Ruger. I didn't like the throat or neck and had him use the CIP dimensions for that. Why?, Foreign necks could be much thicker. Some poor hunter with one of mine might have to use substitute foreign ammo, be a helluva note if he couldn't chamber it. There are considerable variations in the 7x 57, but they are manageable. This first came up when the M21 and 22 CZ Brnos hit the market. Those foreign chambers"weren't the same as in my WinM 54 ( or70)" . This required a trip to Sam's place. Next a search by the Winchester"Missionary" at the factory. Winchester had the records from US Ctg company and available sample rounds from back in the days when U.S.Ctg. had military contracts for the 7x 57 ammo to include Serbia and various South American countries. Answer was that the chamber for the 7x 57 was based ( for the 54 & 70) on what would chamber world wide from available reasonably close ammo. Some countries rolled their own and rather indifferently. I personally rely on Brit Rules of proof and or C.I.P Dimensions often checked against Kenny Howells Epic and simply ignore the rest. The ctg case length/headspace gage will determine usability of cases with differences of 1/2 or 3/4 minutes of shoulder angle relative to difficult to determine length measurements to the center of shoulder radius and shoulder to neck radius. I yet contend that the .275 Rigby HV and the 7x57 are "Sisters Under the Skin" to quote a line from an old barracks ditty. This has been sent at the insistance of Dago Red.
Many thanks for your clarification in this matter. I certainly appreciate it. As one who is not as old as yourself by a fair measure, and far short of your knowledge of these things it is always good to hear answers from someone as knowledgable as yourself. To me it matters little who was right or wrong, if anybody even actually was here, but it always will end in a winning situation to get knowledge like yours put on the table. Thanks again for what you shared on the matter. It was great stuff, and I have filed it away with other tidbits of very worthwhile info I have collected over the years.
Posts: 845 | Location: Central Washington State | Registered: 12 February 2001
Ok I have a couple of questions. I am strongly leaning towards a 270 for this rifle. The barrel will be a cut rifle barrel in half round half octagon. How long should it be? I am leaning towards 22 inches.
Secondly what must be done to a G33/40, exactly to make it feed perfectly?
Posts: 2341 | Location: Moses Lake WA | Registered: 17 October 2000
Tom, thanks for posting that. I never doubted what you said after the first post. I do enjoy your writing and I sometimes get lost trying to follow but the side trails are always interesting. I know Wilsons well, they have a lot of my money.
Posts: 4917 | Location: Wenatchee, WA, USA | Registered: 17 December 2001
Here is an example of a point mentioned earlier. The cartridge on the left is a 7x64 with a 175 gr Hornady RN. it fits in an unmodified G33/40 with a little room to spare. The center cartridge is a 7x57 loaded with the same bullet. Note how much magazine space is wasted with this short cartridge in a long action. The cartridge on the right is an 8x57 with a 250 gr Woodleigh at max OAL. Note how much wider and further the shoulder is over the 7x57.
I already have 2 7x57's and someday will have a Mexican Mauser in that caliber. I don't have and have never owned a 270. I think its high time to correct that problem.
Posts: 2341 | Location: Moses Lake WA | Registered: 17 October 2000
I would be surprised if it needs anything. Wait until it is barreled and see how it works. Just checked to see if I have a .270 barrel and I do. It is a Krieger but it is stainless. We are not going through that again.
Posts: 4917 | Location: Wenatchee, WA, USA | Registered: 17 December 2001
In order for that thing to feed right, it should be checked and modified without a barrel first. One should be able to feed from the magazine smoothly without a barrel. Go to the barre lastly.
Howard, I have a Mexican that needs a barrel and a stock; got a couple of nice blanks too!
Jim
Posts: 5531 | Location: Minnesota | Registered: 10 July 2002
I know that the more specialized something becomes; specific length, weight, diameter, etc, the less tolerant that object becomes to deviation of any type, pretty hard to use a corvette as a family vehicle or a semi-truck as a daily commuter.
I keep hearing all kinds of talk about how Mausers have their; magazine length, depth, and width; their feed rails, and followers specifically designed and engineered for a specific cartridge and that its all most carefully thought out to work properly. Some people even say down to use with a specific bullet.
Now I have those same people telling me I can take an action designed, see above, for the 8X57 mauser and rechamber to the 7X57 � see picture in this thread for the differences in those cartridges � or even a 270 and it will work just as well. Sorry but something isn�t adding up here.
Posts: 2341 | Location: Moses Lake WA | Registered: 17 October 2000
Right up front, so as to avoid any flame wars, I will say I don't know.
But here is a quote from Blackburn's Site. Since they have been making them for 48 years, they must know something!! I would give them a call and ask their reasons why!.
"CNC Machined out of Solid Steel To ensure a tolerance of less than .005 inches, we use computer run machines with custom designed proprietary programs and tooling. Blackburn parts are designed specifically for the caliber that the rifle is being built for. Using AutoCad and CadCam software we can determine if the deminsions are correct before actual machining is performed"
