Mauser M03 - Magazine Disassembly

A topic came up on the Mauser M03 Blog Discussion Forum, about rounds jamming when the bolt was being closed slowly. I'd had some experience with this when using long pointy bullets in handloads, seated out a long way to be close to the lands. As I wrote in the forum, this is asking for it!  The original poster was having a different problem. When the last cartridge was being fed slowly from his magnum rifle magazines, the rim was popping up too high once it cleared the rails. Feeding quickly worked OK, as with my M03s.

Most rifles feed best from the magazine when the bullets are round or flat tipped and standard cartridge overall length isn't exceeded. Most rifles also feed best when the bolt is moved forward briskly.

"But I like the long pointy bullets." :-(  "And I like feeding slowly sometimes." :-|

If I get a jam when I'm feeding slowly it's usually the third round in the magazine that does it. The magazine spring is not pushing up as hard as it was for the first two rounds. The round below the third round (which we'll now call the top round) gets a nudge from the bevel where the bolt head meets the bolt body and starts moving forward too. When the bullet tip of the top round rises up the magazine's feeding ramp the case's rim is levered down, which tilts the nose of the round below it down. This makes the rim of the round below engage with the bolt head/body bevel even better. The tip of the round below contacts the rubber bumper on the inside of the magazine's front wall and digs in a little. The reduced upwards pressure from the magazine spring is enough to help it get stuck in that posture. As the bolt keeps pushing the top round forward there comes a point where the lack of upwards pressure from the round below causes its rim to slip under the bolt face. Bingo - we have a jam.

To reiterate, this only happens if I'm feeding very slowly from the magazine and only with the third (and sometimes the fourth) round. I can always feed the first round from a full magazine slowly and quietly if needed. I'm glad I did when I met this pig shortly after walking away from my car.

Using a dry PTFE (Teflon) spray to make the insides of the magazine slippery was suggested in the forum, based on experience with the particular slow feeding problem I've described. I'll be giving that a go and decided to disassemble the magazine, to clean the insides and help the application work optimally. Gulp! Here's how that went.

- I didn't have a narrow enough punch for the pins at the front of the magazine, so took a small nail and flattened its tip. I rested the magazine on the edge of a small piece of wood, with a cloth between, such that the bottom plate would not be subject to any force.

- What looks like three pins holding the plastic front piece onto the metal sides of the magazine are in fact six short pins, each 7.5mm long. They should only be driven in about 2.5 mm, to clear the holes in the outer plastic walls of the front piece and the metal sides of the magazine. The pins will then be retained by the inner walls of the front piece.

- The two top pins can be driven in further as there is nothing inside of them to interfere, but the four bottom pins should not be pushed in more than 2.5 mm, as they will make contact with the rubber insert that protects the bullet tips. If you feel resistance, stop hammering!

- The pins are easily pushed with gentle tapping. Once they've been pushed in enough the plastic front piece will easily separate from the magazine's metal sides. The pins might fall out so be careful not to lose them.

- The rubber insert can then be prised and pulled out gently. It needs to be, to retrieve the four bottom pins. I used a broad flat tip screwdriver and then some bent nose pliers with smooth gripping surfaces, to avoid marring the rubber.

- The magazine spring can then be pulled out from under the follower. It's asymmetrical, so take note of its orientation. The higher of the two spring tips goes to the back of the magazine, to ensure that the magazine follower pushes the rim of the top cartridge up effectively.

- The magazine follower itself can then be slid out of the magazine, with some tilting to clear the indents in the side panels. During factory assembly a little grease was applied to the underside of the follower, to help the spring's contact points slide as it compresses and expands. I think I'll put a little new grease there, once the PTFE has cured.

To be clear on this, I've only ever noticed jamming when I've been feeding very slowly. It's then only with the third or sometimes the fourth round in the magazine. There's a number of contributing factors and one surefire fix, which Mauser would offer in the form of, 'Just close the bolt quickly and enjoy your rifle!' You'll see in this video, that's exactly what Walter Siebert at Mauser does. :-)