Gewehr 98 shoots inconsistent POI

[wiscoaster]

I've got a 1918 Amberg G98 that's frustrating me trying to find its point of aim for desired point of impact. It seems to be hitting inconsistently in both windage and elevation. The ammo I'm using is PPU 198 gr FMJBT 8 mm Mauser. Half the shots aren't even hitting the target, but where they do hit, the bullets are making round holes. The bore is not bad ... better than some of my other milsurps that shoot a whole lot better. Definitely not "shot out". This particular rifle has the 100 meter rear sight, if that makes any difference. The barrel is marked "S". The bolt is not matching; everything else is matching.

Any ideas on what I should do with / look at on this rifle?

 

[Kleanbore]

Bedding okay?

Screws tight?

 

[db_tanker]

Kleanbore beat me to it.

Also if you can reference that ammo to another 8mm rifle that is a known, good shooter?

 

[GunnyUSMC]

Check the crown on your barrel.

 

[4v50 Gary]

And for safety sake, headspace.

 

[wiscoaster]

Bedding okay?

Screws tight?

All screws tight; there's no bedding, just an embedded recoil lug the front action screw engages.

 

[wiscoaster]

Also if you can reference that ammo to another 8mm rifle that is a known, good shooter?

Yes, same ammo in my K98 hits center and two inches low.

 

[Kleanbore]

there's no bedding, just an embedded recoil lug the front action screw engages.

By bedding, I was referring to chte interface between the stock and the barreled action---the inletting and final fitting.

 

[wiscoaster]

Check the crown on your barrel.

Inside edge of the crown looks good; there's a slight nick on the outside of the barrel rim that doesn't intersect with the inner bore rim.

Pic of nick (best I could get iPad to focus, sorry):
View attachment 1001754

 

[wiscoaster]

By bedding, I was referring to chte interface between the stock and the barreled action---the inletting and final fitting.

Oh, OK, sorry, thought you meant if it had been glass bedded. It looked normal when I had it disassembled and there wasn't any play or noticeable offset when I reassembled, it went back together without having to finagle it or force it and tightened up just fine .... but I haven't taken it apart again yet.

 

[wiscoaster]

And for safety sake, headspace.

Well, I'm going to get shouted at, but I don't headspace my milsurps with headspace guages. Local gunsmiths don't have guages for all the calibers I have and I can't afford to buy one for two or three instances of each caliber. I "headspace" them before first shooting first by eyeballing the casing fit in the chamber, then by bolt closing and extracting, then by shooting off an emptied cartridge w/ primer, then by shooting off a half load cartridge. I figure a headspace issue is likely to show up somewhere along that sequence before I shoot a full load. You're going to hear it and you're going to see it. Several of my milsurps shoot rimmed cartridges that don't have headspace issues.

The fired cartidge casings on this rifle looked excellent. Primer hits dead center. Clean casings with no bulges or misshapen necks. 100% normal looking for a fired 8 mm Mauser casing. Extraction normal, no sticking. Ejection a little weak but improved after cleaning off excess oil on the ejector.

 

[DocRock]

Definitely try another ammo. If you can get hold of some of the Sellier & Bellot 196 grs SPCE. Shoots well in both my M49 Persian sporter and Gewehr 98 sporter.

 

[Dave DeLaurant]

Have you had the barreled action out of the stock recently? If so, check for subtle wear indications along the barrel, like shiny spots. I would also do a close inspection of the stock around the trigger guard screws.

If you don't see anything overtly suspicious going on with your stock/barrel/action interface, assuming different ammo doesn't improve matters, would you happen to own (or could you borrow) a synthetic stock that will accept a military Mauser 98 barreled action? If so, try temporarily swapping stocks to see whether the rifle behaves differently -- that could help narrow down the variables a bit.

 

[CapnMac]

The ammo I'm using is PPU 198 gr FMJBT 8 mm Mauser.

Were it 2 years ago, I'd suggest finding a different ammo--like S&B in a flat base rather than a BT.
Of course, the number of options for 8mauser is not that great in 'normal' days.

That "feels like 2m long" barrel can have funky harmonics, which might explain the "off the target" shots. I've seen these ruined by Bubba attempting to "free float" these. Which is futile, as it's mean to have the barrel supported in various locations along the stock.

Mind, should I live to be 115, I might be cranky and inconsistent, too []

 

[entropy]

Try setting the rear sight up to the 300 meter mark. It works with Mosins.

 

[AMraider]

I would slug the bore and see what size you are dealing with. Then go from there.

 

[lysanderxiii]

Take the front barrel bands off and see how the stock fits in relation to the barrel.

The stock should press straight up against the bottom of the barrel about 4 to 10 pounds.

Next loosen, but do not remove, the trigger guard screws and see if the receiver moves in the stock, back-and-forth, side-to side.

 

[wiscoaster]

Definitely try another ammo. If you can get hold of some of the Sellier & Bellot 196 grs SPCE. Shoots well in both my M49 Persian sporter and Gewehr 98 sporter.

Yes, I think that's my next step before I get too involved, and I actually just ordered some S&B from PSA before I came here.

 

[wiscoaster]

Have you had the barreled action out of the stock recently? If so, check for subtle wear indications along the barrel, like shiny spots. I would also do a close inspection of the stock around the trigger guard screws..

Dave. It's a 100-years old rifle.

 

[wiscoaster]

That "feels like 2m long" barrel can have funky harmonics, which might explain the "off the target" shots. I've seen these ruined by Bubba attempting to "free float" these. Which is futile, as it's mean to have the barrel supported in various locations along the stock.

Yes, barrel harmonics is what the behavior is like, except it hasn't been bubba'ed and the barrel bands have no way to be tightened or loosened; they're just held in place by clips.

 

[wiscoaster]

I would slug the bore and see what size you are dealing with. Then go from there.

The barrel is stamped "S" so it's chambered for a 7.92 x 57 mm cartridge with 154 grain Spitzer bullet of 0.323 in diameter. The PPU bullets are 196 gr and 0.323 in. Do you think the heavier weight is a factor? I'm going to try S&B ammo, but their bullet weight is the same. I don't know what the profile is.

 

[wiscoaster]

Take the front barrel bands off and see how the stock fits in relation to the barrel.

The stock should press straight up against the bottom of the barrel about 4 to 10 pounds.

Next loosen, but do not remove, the trigger guard screws and see if the receiver moves in the stock, back-and-forth, side-to side.

About the best I can do is: everything is tight and firm but not overly tight, and without movement. On this particular rifle only the front action screw has a set screw.

 

[wiscoaster]

Ya know, I just thought of something else that might be a clue: I can't get the cleaning rod to screw in. The cleaning rod threads aren't stripped, but they aren't engaging, and Lock-tite does nothing. I think I need to take another look at the recoil lug, since that's what the cleaning rod screws into, no?
<Later> No, dead end I think. I loosened just the rear action screw and everything still seemed to be firm and tight.

 

[AMraider]

The barrel is stamped "S" so it's chambered for a 7.92 x 57 mm cartridge with 154 grain Spitzer bullet of 0.323 in diameter. The PPU bullets are 196 gr and 0.323 in. Do you think the heavier weight is a factor? I'm going to try S&B ammo, but their bullet weight is the same. I don't know what the profile is.

If every thing looks good then trying several different brands/weights of ammo may get it to group better. After that then maybe a re-crown or counter bore.

 

[wiscoaster]

If every thing looks good then trying several different brands/weights of ammo may get it to group better. ...

Yes, unfortunately right now 196 gr is all I can get. The "proper" weight for the S Patrone bullet is quite a bit lighter, but I can't shoot that unless I want to load my own, which I don't. Heavier weight is going to affect trajectory but shouldn't adversely affect consistency. An undersized bullet diameter will affect consistency, but the PPU bullets are (supposedly) "proper" diameter, so I'm still at a loss. So much fun!! Ha!! If it needs to be re-crowned and counter-bored it's just going back into the gun closet and exist there as a held hard asset.