tinkerfive Posted April 29, 2009 Report Share Posted April 29, 2009 I've acquired a couple of 7MM barrels. Most are of the 22" variety. I also got a 7Mm Remington magnum 26". One of the barrels, a new old stock, is 29". I was thinking of having an array of 7MM's. If I were to convert one of the 7MM Mauser's to 7MM express (280 Rem), what would make the most sense to use, one of the 22 incher's or the 29"? Something is telling me to keep the 29" as 7MM Mauser. I'm looking to hear from some guys that have made the change to 7MM express / 280 Remington. How close in velocity would a 7MM Mauser out of a 29" barrel be to a 280 from a 22" barrel? Tinker Quote Link to comment Share on other sites More sharing options...
z1r Posted April 29, 2009 Report Share Posted April 29, 2009 Be advised that the neck on the .280 is a good deal smaller in diameter than the 7x57. The .280 reamer will not clean up the old neck. The result: a necked neck. Quote Link to comment Share on other sites More sharing options...
Spiris Posted April 29, 2009 Report Share Posted April 29, 2009 How close in velocity would a 7MM Mauser out of a 29" barrel be to a 280 from a 22" barrel? In a good 98 action, the 7mm Mauser, loaded to it's potential, runs about 100fps less than the 280 with the same barrel length and bullet weight. IMO, it's not worth the hassle. The 7mm is one of those old designs that's very efficient, much like the 6.5x55. As z1r mentioned, the 7mm Mauser neck is bigger by some .005 and could cause problems unless you shorten the chamber a bit first, rethread the shank, and then rechamber to 280. Here's a couple links to each case dimension. http://ammoguide.com/?catid=16 http://ammoguide.com/?catid=104 Spiris Quote Link to comment Share on other sites More sharing options...
tinkerfive Posted April 29, 2009 Author Report Share Posted April 29, 2009 In a good 98 action, the 7mm Mauser, loaded to it's potential, runs about 100fps less than the 280 with the same barrel length and bullet weight. IMO, it's not worth the hassle. The 7mm is one of those old designs that's very efficient, much like the 6.5x55. As z1r mentioned, the 7mm Mauser neck is bigger by some .005 and could cause problems unless you shorten the chamber a bit first, rethread the shank, and then rechamber to 280. Here's a couple links to each case dimension. http://ammoguide.com/?catid=16 http://ammoguide.com/?catid=104 Spiris Thanks for the links and I didn't realize that the two were so close. That makes the decision much simpler. It looks like if you were to face off the breach by .0357 that would take care of the neck issue. I don't know if that would also take care of the .4700 Vs .4711 at the base. Thanks again Tinker Quote Link to comment Share on other sites More sharing options...
brian923 Posted July 4, 2009 Report Share Posted July 4, 2009 i was thinking of going this way. i am looking to start buying up some components to build a custom mauser in 7m rem mag, but then, with a little investigation, i see that the .280 AI will keep within 100-150 fps with similar bullet weights, and bun a lot less powder. this would also allow the pressures to stay at a sane level, and burn a lot less powder at the same time. pluse, i won thave to mess to much with bolt face opening, and feed rail work, after all, it will be my first, so i think the simpler the better. for now... Quote Link to comment Share on other sites More sharing options...
Limpid Lizard Posted July 4, 2009 Report Share Posted July 4, 2009 A standard 280 is plenty potent. I've whacked a few critters with one. You will not get a whole lot in return for going AI. That said, I have built a few AI's myself, and if you enjoy playing with them, they are kinda fun. LL Quote Link to comment Share on other sites More sharing options...
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