This allowed more room for the cartridges to stack inside the magazine. To rectify this I used the dreaded demon of gunsmithing, (yes, the Dremel tool), to both thin the the thickness of the follower, and to move the surface of the angled portion over slightly. The 5th cartridge would just barely not fit. On one of the 98's that I converted to 308 the feeding was fine, but I could only get 4 rounds into the magazine. You can always get a replacement part if something goes wrong, but the receiver IS the firearm, and is much harder and more expensive to replace. Waksupi hit the nail on the head! Always try modifications to the 'parts' first, not the receiver. Keep the bolt back, insert a cartridge, push it forward on the follower with your thumb to where the tip of the bullet is about where the tip of the original 8mm would be, and then if the lips are still retaining the cartridge push the bolt forward and see if it feeds better. Anyway-just a few thoughts, you could try positioning the cartridges a little farther forward in the magazine to prove or disprove the possibility before beginning to reshape the feed lips. This would likely take some welding of the lips to build them back up, and then a careful stoning to hit the spot of reliability. Next, I have a M-43 La Corona receiver based rifle that was re-barreled to 7.62mm, but has just the opposite problem yours is having in that the cartridges sometimes jump out of the magazine as the bolt is pushed forward-perhaps every 3rd round. Of course, if it would work, you'd need a spacer in the rear to hold them in that position. So, I'm wondering that if you move the 7.62mm cartridges just a bit farther forward in the magazine if you would notice a difference. However, no work was done to the feed lips, the cartridge was just positioned farther forward in the magazine until it worked. It feeds very well, but resulted in a very long bolt throw. One is a Spanish small ring, probably an 1893 that was originally in 7mm, and it has been altered to feed 7.62x39mm (much shorter) by spot welding a spacer into the rear of the magazine box to move the cartridges forward in the magazine well. I have two rifles in my accumulation that might illustrate the point. Of course, the feed lips are machined for the cartridge that they are intended to work with. Bullet style/design and weight can also play a part in feeding, the O.A.L. Also worthy of consideration is the overall length of the cartridges, 2.810' for the 7.62mm and 3.250' for the 8mm. 434' at the location just below the shoulder. 470 just above the extractor groove, but does a longer taper to. 456' just below the shoulder, whereas the 8mm is also.

470' just above the extractor groove and tapers to. Also to consider, the 7.62mm can be described as being fatter than the x57 cartridges. Originally for the 8x57mm cartridge, the 7.62x51mm is a bit shorter. These rifles were converted by the Spanish to approximate the CETME assault rifle in size and shape for training purposes.

I think 405grain's answer is a good one, and likely the correct one. Without researching what to do it would be easy to mess up a receiver. The process isn't difficult, but requires spending the time to learn the how's and why's of doing it. I just finished modifying two vz-24's to feed 308 about two months ago. Before you attempt anything you'll need to read up on altering Mauser feed rails for shorter, fatter cartridges like the 243 Winchester & 308. Modifying the feed rails should be done slowly with stones, checking frequently to monitor progress. You are correct in assuming that a dremel tool would be the kiss of death for something like this. The feed rails will need to be adjusted for the cartridges to strip smoothly from the magazine. A stronger magazine spring will not help to lift these cases through a space that it too narrow for them. The problem that your experiencing is because the shoulder diameter of the 7.62x51/308 case is greater in diameter than the 8x57 shoulder. The 8x57 feeds properly because that was the round that the action was originally designed for. The feed rails on Mauser rifles are machined specific to the cartridge that that action was designed for.

Fr8 spanish mauser 308