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gunnutty

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  1. The rounds are both .30 caliber. The 7.62 X 54R holds a little more powder (maybe?) an the MN is built around this cartridge. With the 7.62, no action alteration would be required, and feeding is flawless. I think the idea advanced in another thread about chambering the 7.62 X 54R with a .308 barrel is a better idea. Better selection of bullets, and a new-condition modern bore. If you just had to have a different cartridge, I'd recommend the .303 British over the 30/40, just for better available components (brass). The two cases are nearly identical, with the 30/40 having a slightly longer neck. You might even be able to get a "pull" .311 barrel (Mauser or Enfield) on the cheap.
  2. Rather than tearing apart the magazine box, I'd recommend having taper "blocks" (top to bottom and vise-versa) in the front and rear of the magazine. These wedge-shaped blocks would do the same thing that the Siamese magazine does. Those wedges should be easy to make from either aluminum or steel plate scraps. I'd do some geometry on the rear to ensure the angle is correct. The only kicker is that the overall internal magazine length will have to be very close to the overall length of the loaded cartridge. The blocks will ensure proper initial alignment, the close overall length will prevent the cartridges from shifting. I don't think that the issue is having a rim; it's having the SEMI-rim. If it were a full rim and provided the shooter loaded the cartridges right in the first place, the top cartridge would always stay ahead of the case below it. Instead, the Swift rim is shallow enough to allow the bottom case to slide forward of the top case, yet large enough to cause feeding problems when this occurs.
  3. Never needed to block a magazine. If the cartridges are moving forward preventing reliable feeding, you probably need a block. You can play with a "junk" follower, shorten it, and TEMPORARILY, using adhesive, put an aluminum block in the magazine front. Or you can ride with the rifle muzzle-up. The feeding issues maybe aren't related to the cartridges moving forward. Dunno.... Perhaps a more experienced member has ideas.
  4. The Swift has a rim... Are you loading each cartridge in front of the other when loading the magazine? If the cartridge on top has its rim behind the one below, if will probably push it forward. The swift is a "semi-rim", and this is supposed to alieviate the issue. If it isn't then a magazine block might be the way to go.
  5. About the same as a .280 Rem. I'd go with the .280. It'll feed better.
  6. A .17 Mach IV or .17/.357 would be neat. Or better yet, a .17 Ackley Hornet. Shooting phonograph needles can be such fun!
  7. I think that the factory that made SB actions also made the military 93s/98s. If that's the case, I doubt that they would have converted to an investment process. They are probably straight millings.
  8. MorganBoss: The M-N follower assembly is a marvel, isn't it? When running the heavier rounds through the magazine, I wonder if the follower springs are strong enough to lift the bullet end of the cartridge? I'd love to see some details photos of what you've done. My M-N is just sitting here, waiting for something to be done to it. I have an old American Rifleman article in which the author notched the receiver after the stripper clip guide and moved the bolt handle back accordingly. Much easier to manipulate, and expands the scope base opportunities. A rear base could potentially straddle the clip guide hump. I picked my M-44 up for a song at a show. It's a Polish model (so I was told) and in very nice condition. I'm very impressed with the metalwork and function. Much better looking than some of the WWII era Russian models I've seen.
  9. The biggest problem with coverting to another cartridge is the magazine. The 7.62 X 54R is a short, fat, stubby thing. Actually, discounting the rim, I think it's a damn, fine cartridge. It performs almost as well as the '06 in terms of out-of-the-muzzle performance. The M-N magazine is made specifically for this cartridge. Anything with a longer body or larger diameter caliber just won't work as-is. I think an easy solution to getting a different cartridge to feed is the .405 Win. The rim and base diameters are VERY close. The .405 is around 0.100" longer, but that's close. I'd do the following: 1. saw the magazine immediately behind the integral magazine feed ramp. 2. mill or file the feed ramp 0.100 deeper, add the bevel incline back. 3. individually heat each side of the magazine shoulder stop red, then flatten between two steel plates, eliminating the shoulder. 4. weld the two magazine parts together again (eliminating the shoulder should lengthen the rear of the magaine enough so the two parts will meet or actually overlap a bit. 5. mill the underside of the reciever opening to match the taper of the .405 (plus the width of the magazine walls). 6. assemble the mess, check for feeding, and tweak as necessary. 7. open the magazine opening in the stock to accomidate the wider magazine. Half hour job, right? Heh. No, it'll take some work. I don't view this as that different than shortening a M1917 magazine box, straightening the bottom strap, and re-drilling the forward guard screw hole. Where there's a whip, there's a way. The .405 would be very fun in an M-N. It's probably the closest fit of any cartridge, other than a wildcat based on the 7.62X54R.
  10. I have no issues with investment cast receivers. Sako and Ruger have certaily been pioneers in the casting field, and I'd feel safe behind any of their products. What does investment casting offer the consumer? At least some cost savings on the product. To the manufacturer? Reduced time needed to finish the product, and reduced expense in finishing machinery. The process involves using centrifugal force to move the molten metal into the mold; slag and lighter impurities "stay on top" so to speak and shouldn't enter the mold. Porosity or air entry is not an issue either. Every nook and cranny in the the mold is completely filled. The grain structure is VERY uniform and controlled. Parts need little, if any, final finishing. I think most of today's mass-produced bolt-action recievers with "flat" bottoms are probably investment castings. Round bottom recivers start as tubes. Winchester refers to their receivers as "precision forged". I suspect that that's another way of saying investment cast, or the action starts as a casting prior to forging.. The rear underside of the reciever on post-64 Mod 70s looks like a casting to me.
  11. Why not reload the cartridge with a mild faster powder and lighter load? 4198 and RL7 and excellent powders to play with to eliminate the muzzle blast. You can handload to any 30-30 velocity you'd want.
  12. MorganBoss: I'm intrigued by your M-N safety modification. Do you have some detail photos of it?
  13. This is not Gibbs' data. It's Wolfe Publishing, I believe Roger Stowers. The book was printed in 1991, and he notes specifically about watching for pressure signs. These are listed as MAX. Also note the 26" barrel used in testing. I just put the data here as a reference. I'd say the pressures run in the "heavy" '06 range, or modern magnum cartidges. I look for the same pressure signs on a Gibbs as I would an '06 when handloading for a bolt actioned rifle. I can exceed factory velocities for an '06 virtually every time with handloads; I would definitely say I could do this 100% of the time with 8MM loads. I'm matching a specific load to my particular rifle, resized to my chamber and using components of my choosing. Velocity for a given caliber is pretty much a function of case volume. You can make the case short and fat, long and skinney, or put a belt or flange on the thing. The reality is that for a given barrel measured from the case mouth to the end of the barrel, for a given caliber and pressure, velocities should be identical. An improved 8MM-'06 should outperform an 8MM-'06 by approx. 75 to 100fps. I will of course use the dirty Economics phrase "All things being equal". Some barrels are "fast", allowing incredible velocities. Others drag, never meeting or exceeding anyone's expectations. I'd say the 8MM barrel used to gather the 8MM Gibbs data may have been fast. I know other Gibbs data from this book was on par with what I experienced.
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