I have started to build a hunting rifle for my brother. As he won’t be using it much, and it might not receive the best of care, the intension was/is to build as cheap as possible. Naturally that leads to problems…..
The gun is built off a 98 Mauser action. Mauser stock “sporterizedâ€, 8mm Mauser barrel with iron sights, Bold Optima trigger, Weaver see-thru ring/base, Swift 6-18 scope, Kick EEZ recoil pad. Yes, it’s a hodge-podge of parts!
The stock has pillars installed (Front pillar on trigger guard was removed). The action is bedded to the stock via Devcon. The front and rear of the trigger guard is bedded. The scope rings are in perfect alignment. The bolt lugs were lapped before the barrel was installed. Trigger pull set at 3.5 lb.
The bore has some slight pitting, but I would consider it in fair condition. I fire lapped the bore with the wheeler engineering bore lapping kit.
My problem= I can not get it to shoot a good group. I have tried Remington factory load of 170gr Core-Lokt along with a batch of hand loads. It will group two out of three rounds close together, but almost always has a flyer. The flyer is always 6“-8†high. A 6â€-8†flyer is not me (the shooter). The flyer seems to usually be the second shot for some reason with the third shot close to the first.
The hand load is Win Brass, CCI Benchrest Primers, Hodgdon Benchmark 43.5-47.5 gr., Hornady 150gr SP. The Hornady bullet measures .323. I drove a lead slug down the barrel and the groove diameter measures .325 with a bore diameter (small dia of bore, between the lands) of .314. I used my RCBS digital scale to measure every charge. The scale was turned on one hour before use. I had a lot of deviation within the same powder charge weight. 43.5gr=s.d. 44.03, 44.5gr=s.d. 119, 45.5gr=s.d.142, 46.5gr=s.d.54.74, 47.5gr=17.66, Rem Core-Lokt=s.d. 13.26. Most of my hand loading is for .22 cal stuff , I weigh every charge, and my s.d. is usually low, in the teen’s at most. Not sure why I had such a larger s.d.
I have tried a pressure pad and free floating the barrel. Free floated gives tighter overall groups, but still has the flyer. The only thing I can come up with is it has an extremely long throat/free bore. Using the Stony Point O.A.L. gauge and the Hornady 150gr, the bullet completely leaves the case before contacting the rifling. I didn’t measure it, but it looked to be 1/8†or so of travel before contacting the rifling. I think from now on I’ll measure the O.A.L. before spending time mounting a old barrel………… Maybe even making a cast of the chamber/throat. O well. Live and learn right?!
So what you guys think? I got a wore out barrel? (Please only constructive comments)
Thanks. Billy
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Billy, I would try a heavier and longer bullet such as the 185 Remington or the 195 Hornady and the recommended amount of a slower burning powder than Benchmark. I have had good luck with H4831sc in mine.Hopefully after a different load your consistancy will improve.If not you can start looking at other things.

I have H4831sc powder but all the books I have contain no load data. I looked on the Hodgdon website and there is no data there either for H4831 in 8mm. What data do you have for H4831sc in 8mm? (including for the 150gr SP if you got it) Thanks. Billy

Billy Like Ron has already suggested try a heavier bullet. I have had very good sucess with the 200 gr Speer and IMR 4350. Seat the bullet out as far as possible and still have the round function trough the magazine. Both the Speer and Nosler manuals have data for 200 gr bullets. Hope that helps.

Steves Pages shows loads for 4831 IMR and Hogdon and 150 grain bullets, does not specify sc. use your own judgement start low and work up.I have found his website very usefull in the past.

Billy; the Hodgdon #25 has H4831 data for the 8mm.

150gr bullet- H4831, 53.0=2183, 57.0= 2452fps
the same data is used for 170 gr and 225 gr bullets.

I don't know how many barrels you have pressure lapped/fire lapped, but it will move the throat forward FAST

If you have a Lee factory crimp die I would give that a try, it will improve your estreme spreads and possibely accuracy. Some Hornady 220 gr bullets should let you get close to the lands and will make better use of the 4831. Good luck

Ron,
Thanks for the heads up on the Steves Pages. I used to have several places like that saved. Couple weeks ago my hard drive crashed, lost all my website favorites
No one around local has any 8mm bullets. I guess I should have ordered heavier one's from the start but deer will most likely be the only thing ever shot with this gun, so I thought 150gr would suffice........ Thanks again. Billy

I do not think it is any of the above.
Remove the scope and mount and fire 5 rounds of any load you have at a target distance of 25 yards. I will bet from a rest you have a jagged hole.
My 8X57 Mausers, perfect barrel to all but shot out and pitted barrel, never throw fliers. I do load 180-220 bullets and never load to maximum. I still use the original NRA Reloading manual.
The only bedding I do on the action is the front lug area and the chamber area of the barrel.
I promise your 8X57 Mauser does not have a mind of its own. The scope/mount is your first inquiry, the excess binding epoxy bedding is second and heaver longer bullets is third.
Good luck.

you can always buy a new bbl or ave the one you have removed and some threads taken off
and re cut so the throat is shorter.
you may also want to look at the crown.

I've had the Hornady 150s shoot quite well from some pretty pitted 8mm barrels. I'd also suggest a change of powder. Try 4895 (any of them) and work up to 49 gr. The length of throat is normal for milsurp 8mms.

A consistant 6-8" flyer indicates 4 possible causes (or a combination). bedding, a damaged crown, the mounts (including bases) are loose or the scope is bad. As it appears the bedding is ok (double check it) take the scope off and test it with the iron sights. If it shoots good consistant groups then check the scope bases and rings to see if they are correctly mounted and the screws tighten the bases down solidly against the recieiver. If the mounts are tight put a scope of known guality on the rifle and test it. If it still throws the flyers have the muzzle inspected for wear and or damage and recrowned (may need to shorten the bareel a bit to get past the damage).

Larry Gibson

There is no good reason to handicap the 8m/m Mauser with light weight bullets. Hornady's fine 220 grain bullet makes the venerable 7.9m/m a heavy hitter. There are gobs of 200's that will do an outstanding job too as will Remington's 185 grain Core-Lokt. Another reason to use heavy bullets is that the sights you left on it were probably regulated for them from the git go.

The original 8mm barrel was probably made for the 150/154gr bullet. I'd suspect the scope may be shifting it's internal adjustments due to recoil, the bedding is binding in recoil or both.
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I'd take the scope off and using the original iron sights, shoot some groups at 25yrds using some 8mm Military surplus ammo. It will be in the 150gr bullet weight range. While not match quality it will take any ammo varibles out of the mix, will be what the rifle and barrel was made for originally, and will remove the scope as suspect all in one session. If fliers are still present, back up and try to elliminate other potential problems such as a bad crown, bedding, etc. If no fliers appear, reinstall the scope and try again going forward to ellimiate either the scope (&/or mounts) or lastly the ammo.
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I have great luck w/ Sierra 175gr Hunters and Speer 200gr over IMR4320. You can also get 170gr gas checked lead that shoot great at 2000fps for targets.

I get groups under 3 inches using the "heavy ball" ammo and just replacing the bullet with the 185 grain Remington bullet. I feel you have a scope issue, loose screws or bedding not done right. I had an old Turkish mauser that had the 5 inches of rifling wore out completely in front of the chamber that still would shoot into 3 inches at 100 yards.

I don't know if the SD's you report are abnormal, but it makes me think that you may have an ignition problem. Check firing pin protrusion, I have a manual that gives specs. Also disassemble the bolt and check for cosmoline or debris inside the bolt.

Try another scope first.


I also get good groups from Hornady 150's from a pitted barrel, with H4350.

Germany's adoption of a pointed 150g bullet is what spurred the evolution from 30-03 to 30-06. The rifles have been made for light bullets since 1905.

There is still hope that the cheap rifle project hasn’t failed. I loaded up a small batch cartridges with H4831sc and a primer change. Three rounds each group. No other changes made.
Win. Case, Hornady 150gr SP, CCI 200 Primers, Hodgdon H4831SC
53gr: ave 2143 fps, E.S. 22.32, S.D. 13 1.25†3shot group
54gr: 2233 fps, sun behind cloud/lost 2 of 3 shot group data 1.5†3shot group
55gr: ave 2282 fps, E.S. 30.17, S.D. 15.52 2.5†3shot group

In contrast: Benchmark loads: 43.5gr= 4.5â€, 44.5gr= 6â€, 45.5gr= 8.5â€, 46.5gr= 10.25â€
Rem. Factory Core-Lokt ave 6.7â€

I see a pattern of tighter groups with milder loads. I think I’ll work up some more H4831SC 54gr loads to just verify what I grouped today. If I can get consistent groups 3†or less I’ll be happy.
I would like to thank everyone for the constructive input in their efforts to resolve my problem.
I’m still amazed that just a change in powder/primer made such a huge difference! Go figure!
Thanks again, Billy