howdy, all. I fired some reloaded Winchester factory ammo through my M1910 7mm Spanish Mauser roller, and it was pretty harsh results at 50 yards. So, I want to check my observations, and see if I am on the right track, and get your inputs on the reloading supplies. Observations: I hammered out the jacketed rounds and powder up front, and fire formed the brass using BP and cream of wheat. It worked very well, all the brass was noticeably fatter and the next was so wide that the .284 jacketed round swam around. I also casted (cast?) the chamber with Cerosafe, and mic'ed the rifling about an inch in at .286-.287. In fact, after fireforming, the inside diameter of the neck was mic'ed at .287 as well. So, it seems this chamber is quite a bit roomier than the standard Mauser chamber. I used the Lee Collet die to squeeze the neck down, but even still, the rounds were quite loose and spun easily. I don't have a factory crimp. I reloaded 43 grains of the powder that came with them, some kind of spherical powder. I fired the gun at 50 yards, and got about an 18" group. Questions: 1) Was this 7mm round back in the day a lead or jacketed round? 2) The bore seems pretty wide for a .284 projectile. I am hoping the bad accuracy was from lack of crimp and the bullet swiming around in the barrel on the way out. Does this seem reasonable? 3)I cleaned the bore out with Butches, and lots of blue (copper) came out, but otherwise, the rifling looks good and I don't see any imperfections. Are problems in this kind of rifle bore usually visible to the naked eye? 4)I was going to order .287 hard cast bullets from Montana Bullet works. Has anyone used them before? 5)The Winchester brass seems ok, but Midway offers Remington (out of stock, no backorder), Winchester (Seasonal), Nosler (coming soon at 4 x the price) and something called Norma. Is there a better brass to use for 7mm? 8mm? 30-06? 6) I expect a .287 lead bullet to seat firmly, but should I factory crimp anyway?
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