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Gunsmithing Feed issue on 98 Mauser

CowboyBart

CowboyBart

Sergeant
Full Member
Minuteman
Jun 14, 2007
477
8
North West WY
Can I get some tips and pointers on how to correct this feeding issue:







It worked fine when I was using 110gr bullets for fireforming. Now that I am using 165 and 180 gr bullets it doesn't want to feed from the left side. Right side does fine. It runs the bullet nose into the right side of the barrel breech. It looks like the bottom of the feed rail gets thicker as it goes forward. Do I need to gently take away metal from the bottom (thicker part) or do I need to slightly take metal away from the left rail to widen the rails??
 
Ok a couple questions. What is your cartridge overall length? What are you if fire forming to?
On most mausers the right side mag lip will help guide in the cartridge. Same thing from the other side. I don't have a 98 here but have a 96 and worked a few rounds through it to make sure remembered right. So be careful if mess with mag lips.
 
COAL = 3.335"
Fireform to 30-06 Ack Imp

I'm guessing that the orig 8x57 shoulder is more rearward and narrower. In order to make the 06 AI case work it looks like I need to remove a small amount from UNDER the Left feed lip. In other words: go forward a small amount removing .010"-.030" from under the left feed rail.
 
The length is what is messing you up. Can try smoothing it out under the feed lip. Is it catching on the shoulder or the bullet tip?
 
You have to adjust the taper in the feed lips. If you look at it from underneath you will see it, slowly adjust that angle and the "hump" toward the fwd end. Real hard to explain, you need to check some Mauser forums and YouTube. You have to go slow and check often. If you go too far.... It's done. You may have to adjust the right side after fixing the left. The lips and box ( lol ) have to be adjusted. The 8x57, and 30-06 have taper and feed no problem. ( the 06 is a stretched 8mm so length to shoulder isn't the problem, ) when you ackleyed it you straightened the case out, removing the taper, so FF loads worked great, new straight walled cases not so much.

I spent 16 hours getting a 98 action to feed a .416 ruger... It takes patience. But it will feed upside down fast or slow. You want the nose of the round in the chamber as the the lips start to release the round up into the bolt face..
 
I got it feeding. Thanx Panzer & Clark.
I started with a file about 50% -75% up the left rail. I didn't want to go past 80% because it looks like that bumps the case from the right side straight. I feared that if I took metal from here the right side case would start giving me problems. Below the left rail there was a pronounced bump that I believe was for kicking out the 8x57 case from the mag well. I Dremeled this bump out for about a 1/4" , thus moving the shoulder kicking bump forward. I was 92% there and still couldn't get it to feed 100%. I then stroked the file no more than 20 times the length of the left rail - WA-LA.
Feeds pretty good with the 4 dummies using FMJ bullets seated out to max. I'll have to check with a 200gr RN as that may not glide into the chamber, but instead bump into the breech of the barrel.
 
Peter Paul Mauser used a formula for determining the feed lip profiles according to the dimensions of the cartridge that was to be used. It has to do with the triangular profile of the cartridges as they were stacked atop one another in the magazine. I don't have the formula handy. Do a search.

In my '37 98, I just keep it 8 MM, which feeds perfectly, like a hot knife through butter. If I had to have a different caliber, I would wildcat the 8 case.
 
Last edited:
Marine,

Although I don't see any larger caliber as an improvement, as the 200 grain Partition kicks ass at 2700, I believe larger might be accomplished without mods to the rifle. The 338 is doable directly with the x57 case.

What would you do to run 366 or 375?
 
longshooter said:
Marine,

Although I don't see any larger caliber as an improvement, as the 200 grain Partition kicks ass at 2700, I believe larger might be accomplished without mods to the rifle. The 338 is doable directly with the x57 case.

What would you do to run 366 or 375?
Click to expand...

Hmmm...I must've missed this reply. There's nothing to do, per se, as the 9.3x57 runs fairly well without mods through the small and large ring Mausers. As for the case, if the chamber is done correctly, just run 8x57 brass through the FL die and you're done. If the chamber is a bit...odd (i.e. long), some folks neck up to .375 and then neck back down to .366, adjusting the die for proper headspace (similar to fireforming a wildcat case with a false shoulder). Not sure if that answers your question or not(?)....
 
MarinePMI said:
Hmmm...I must've missed this reply. There's nothing to do, per se, as the 9.3x57 runs fairly well without mods through the small and large ring Mausers. As for the case, if the chamber is done correctly, just run 8x57 brass through the FL die and you're done. If the chamber is a bit...odd (i.e. long), some folks neck up to .375 and then neck back down to .366, adjusting the die for proper headspace (similar to fireforming a wildcat case with a false shoulder). Not sure if that answers your question or not(?)....
Click to expand...

The problem with the 366 or 375 x 57 is that you start running out of shoulder for positive headspacing.
 
longshooter said:
The problem with the 366 or 375 x 57 is that you start running out of shoulder for positive headspacing.
Click to expand...

Interesting, as I have not had that issue with the 9.3x57mm. .375 may be an issue, but I haven't played with that round yet, only the 9.3mm/.366.
 
There is no problem with head spacing these rounds. There is almost three times the surface area with a 9.5 case to headspace than there is with the belts on standard magnum cartridges.
 
We are talking about the x57 case of the Mauser. Increasing the diameter of the bullet reduces the shoulder. The belted round magnums provide a positive stop, but for accuracy, most peeps will headspace on the shoulder, same as the bottleneck cartridge.
 
Yes, we are talking about the 57mm case. Yes, increasing the bullet diameter reduces the shoulder. However, even with a 9.5mm (.375 diameter) bullet, the surface area available for the cartridge to headspace on is far greater than that available on a belted magnum.
Whether peeps headspace on the shoulder or not is irrelevant.
 
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