FR8 (Mauser) feeding issue - the continuing saga

[HumptyDumpty]

I originally posted about this issue in the military rifle section, but given how the situation has progressed, this sees to be the more appropriate place.
See the photos for the problem; they are worth a thousand words (though they are annotated). I have tried three different springs, to include a brand-new, extra power spring, from Brownells. It seems that the feed ramp angle is too steep, causing 308 rounds to tip upward, until the case head slips beneath my bolt. To test this, I tried some 8mm ammo. They begin to enter the chamber, which straightens them out, before the problem can develop. With the 308 rounds, I am experiencing this problem about 75% of the time.
Thoughts? I have very little in the way of precision tooling, and I know dremels can be dangerous in these situations...

[405grain]

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

[Texas by God]

Does it feed better from the right side or the left side of the magazine?

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[Der Gebirgsjager]

I think 405grain's answer is a good one, and likely the correct one. These rifles were converted by the Spanish to approximate the CETME assault rifle in size and shape for training purposes. Originally for the 8x57mm cartridge, the 7.62x51mm is a bit shorter. Also to consider, the 7.62mm can be described as being fatter than the x57 cartridges. The NATO round measures .470" just above the extractor groove and tapers to .456" just below the shoulder, whereas the 8mm is also .470 just above the extractor groove, but does a longer taper to .434" at the location just below the shoulder. So, they are shaped differently. Also worthy of consideration is the overall length of the cartridges, 2.810" for the 7.62mm and 3.250" for the 8mm. Bullet style/design and weight can also play a part in feeding, the O.A.L. Of course, the feed lips are machined for the cartridge that they are intended to work with. I have two rifles in my accumulation that might illustrate the point. 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. It feeds very well, but resulted in a very long bolt throw. However, no work was done to the feed lips, the cartridge was just positioned farther forward in the magazine until it worked. I will attach a photo of it. 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. Of course, if it would work, you'd need a spacer in the rear to hold them in that position. 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. 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. 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. 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.


Click to enlarge.

[HumptyDumpty]

I have tried a variety of starting positions for the cartridges, and while sliding them a bit forward does help somewhat, the issue largely persists. I hadn't referenced the cartridge dimensions in the areas noted by 405grain, but he has confirmed my suspicions. It is difficult to tell in the photo, but the Spaniards did install a spacer, in the front portion of the magazine well. As I understand it, the 7.62 rounds would sometimes hang-up when attempting to ascend the feed ramp.

Is there a particular feed-rail width that is considered ideal, or should I simply remove material, until proper function is achieved? Also, I am a bit of a novice (as you can probably tell), but consider this an excellent opportunity to gain some experience, and acquire useful tools. When you say stones, what exactly do you have in mind?

[HumptyDumpty]

Does it feed better from the right side or the left side of the magazine?

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If there is a difference, it is slight; I really couldn't say for certain.

[Texas by God]

I’ve had luck leaving the rails alone but grinding back the receiver web Underneath each rail to let the fatter round nestle in a bit more to the outside. This has worked on a 98/.358Norma, a 38 Arisaka/8x57,and a P14 Enfield/.450 Marlin. It may or may not work in your case.
Flame away, but a steady hand and a Dremel sanding drum does a pretty good job on this.

[Der Gebirgsjager]

Well then, if grind and file the feed lips we must, then in your photo #2 right where the shoulder is contacting the right side of the receiver is a good place to start.

[waksupi]

Before you start to grind on anything, try different followers. That can solve the problem many times. They all may look alike, but they aren't. Maybe one from a Spanish Mauser that had been chambered for .308 would work.


Also be sure to ram the bolt forward when chambering. If you try to do it slowly, a Mauser will never feed correctly. They were designed as a battle rifle, treat them that way. Also when ejecting a round, rack the bolt back hard.

.308 based cartridges are the most finicky to get feeding correctly.

As an afterthought, you may also try reshaping a sacrificial follower to try for a good feed. Golden rule of working on guns, always work on the cheapest part that you may have to replace. Bugger up the action, and it's scrap metal.

[1006]

I have an FN Commercial Mauser that was factory chambered for a 257 Roberts. I had it rebarreled to a 7mm-08. I am still irritated that my very experienced Mauser gunsmith did not warn me that it might not feed well before he did the work. 7mm-08 is a 308 family cartridge, the 257 is a Mauser family cartridge. I should have gone with 7x57 or any other Mauser cartridge.

Good luck, there are a few Mauser gunsmithing books out there....

I have tried removing the spacer, it helped with long loaded heavy bullets.

[Texas by God]

I have had two 22-250 98 Mausers, a small ring 98 .243 Win, and a 98/22 that I rebarreled to .300 Savage and later rechambered to .308 Win. They all fed perfectly with the (obligatory-home beveled so the bolt will close) military follower. I guess I’ve been lucky. Waksupi’s different follower suggestion is a good one. From my understanding the Spanish FR7 is a 1916 (93) 7x57 converted to 7.62 and the FR8 is a 1943(98) 8x57 converted to 7.62.

[HumptyDumpty]

I've ordered two "Generic Mauser 98" followers, with no guarantee as to which country they are from. I'll try both, and modify one, if necessary. I suspect that the feed rails will also need attention, but this seems like a good starting point. This rifle happens to be in decent shape, shoots well, and the numbers all match. I had actually been looking for an FR8 that wasn't outrageously priced for a while, and was very fortunate to come across this example at a local pawn shop.
Do modern gunsmithing courses still cover this older stuff? The few local guys I can find always seem a bit taken aback by my guns (though I do have a few modern firearms as well). For these reasons and more, I am increasingly interested in getting some formal instruction.

[HumptyDumpty]

I have an FN Commercial Mauser that was factory chambered for a 257 Roberts. I had it rebarreled to a 7mm-08. I am still irritated that my very experienced Mauser gunsmith did not warn me that it might not feed well before he did the work. 7mm-08 is a 308 family cartridge, the 257 is a Mauser family cartridge. I should have gone with 7x57 or any other Mauser cartridge.

Good luck, there are a few Mauser gunsmithing books out there....

I have tried removing the spacer, it helped with long loaded heavy bullets.

How bad is it?

[1006]

I can not remember which side of the mag stack does not feed. But, every other bullet requires me to use my left hand’s fingers to guide the round into chamber as I move the bolt forward.

[Larry Gibson]

Is the spacer still in the front of the magazine?

[405grain]

waksupi hit the nail on the head! Always try modifications to the "parts" first, not the receiver. 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. 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. The 5th cartridge would just barely not fit. 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. This allowed more room for the cartridges to stack inside the magazine. It may be advantageous to try removing some material from the face of the angled portion of the follower, as this "might" relieve some of the binding force pushing the shoulder of the cartridge against the feed rails.
Again, I must reiterate this: Do not attempt to modify the feed rails on your receiver until after you have read through a couple of old school gunsmithing books about sporterizing Mausers and have acquired a confidence in how the process works. Sporterizing milsurp rifles was a popular thing for decades after WW2, and though the supply of old bolt actions has dried up, and the bulk of gunsmithing has shifted to the AR platform, the older information is still out there.

[Gtek]

Maybe I missed it, single round feed from follower or one underneath and creating same result?

[HumptyDumpty]

Maybe I missed it, single round feed from follower or one underneath and creating same result?

As long as I actually push the round down into the magazine first, it makes no significant difference.

[1006]

Larry:



The spacer is installed in my FN, but I have tried it with and without the spacer to allow long bullets to fit in the mag. But, the gun shot just as well with the standard length bullets. So, I put the spacer back in. I have it setup with iron sights.

[HumptyDumpty]

I just tried one of the alternate followers, and it does make a significant difference, though things are not quite right yet. With this follower, I can only fit four rounds in, and the fourth does not feed very well; it really drags along the left rail, and must be seated further forward than the rest. The remaining three feed smooth as butter, regardless of position in the magazine, or how quickly I work the bolt. This new follower is significantly dissimilar to the original, as (I hope), the pictures show; longer, taller and wider. I do have another follower inbound, and will try that next. However, this one might just work, with some modification. Also note, that I reverted to the original Spanish spring, as the extra-strength spring only seems to be exacerbating these issues.Attachment 260049Attachment 260050