Crazy flyers! Swedish 8mm reloads in 8x57 Mauser

[Volhv]

Rifle is a k98 that fell victim to Bubba's Black and Decker.
I managed to save it by making an excentric bushing for one of the misdrilled holes, and drilled a 4th to utilize standard 2 peice bases.
I have a compact leupold sxope on it from the early 80's.

Bore is quite pitted, but lands are strong.

I've been shooting reloads consisting of 218 grain swedish pull down bullets and powder. The pictured groups are 45.2 and 45.5 grains of the swedish flake powder. These were shots 12-16 and 6 to 10 respectively on different days. oal is 3.250

I'm shooting the gun off of sandbags at 100 meters. Its sitting in a israeli stock that fell victim to Bubba's rotary file as well. I have the barrel free floated minus an inch behind the bayonet lug. Action is epoxy bedded. Some of the other loads I've tested average about 3 inches for a 5 shot group.

Any thoughts or ideas would be greatly appreciated.
Thanks!

 

[Andy]

Rifle is a k98 that fell victim to Bubba's Black and Decker.
I managed to save it by making an excentric bushing for one of the misdrilled holes, and drilled a 4th to utilize standard 2 peice bases.
I have a compact leupold sxope on it from the early 80's.

Bore is quite pitted, but lands are strong.

I've been shooting reloads consisting of 218 grain swedish pull down bullets and powder. The pictured groups are 45.2 and 45.5 grains of the swedish flake powder. These were shots 12-16 and 6 to 10 respectively on different days. oal is 3.250

I'm shooting the gun off of sandbags at 100 meters. Its sitting in a israeli stock that fell victim to Bubba's rotary file as well. I have the barrel free floated minus an inch behind the bayonet lug. Action is epoxy bedded. Some of the other loads I've tested average about 3 inches for a 5 shot group.

Any thoughts or ideas would be greatly appreciated.
Thanks!

I've shot that bullet and that powder quite a bit in the 8X57, and posted about it here on CGN.

45.0 grs is a very mild load. In my gun it gave about 2100 fps, with 46.0 upping that to about 2150 fps. In my gun, with my powder, I would not go faster than 2350 fps, which would require about 50.0 grs. I would never do load development on unpublished powders without a chronograph, using MV as my pressure indicator, in this case ~2300 fps after finding where approximately the Swedish powder fell with regard to Powder Burn Rate in the 8X57, in this case slower than IMR4064.

Why did you settle on 45.2-45.5 grs? That's a very narrow range at the "Start Load" side of things. Was it with that bullet and/or that powder that you shot 3" groups in your gun?

You might have barrel and/or bedding issues, but you can't yet rule out the possibility that your loads are contributing to the poor groups.

 

[bigedp51]

There are two ways to tune a rifle.
1. Tune the load for the best accuracy.
2. Tune the rifle for the best accuracy.

Both methods control your barrel vibrations. The torque of the action screws can control barrel vibrations along with the forestock up pressure on the barrel.

Military rifles were tuned to issued ammunition, bottom line it's your load or your bedding that has the biggest effect. If you are shooting boat tail bullets the barrels crown can have a big effect. Meaning any unequal gas flow over the bullet can cause it to tip and yaw.

 

[oppy]

I had a Husqvarna Mauser 98 Large Ring that exhibited this same behavior. It was a rifle I took in trade. I tried several things (including moving the rifle into different stocks). Finally I got around to using some Go/No-Go gauges. It turns out that the throat was worn out. Maybe that is your problem?

 

[MiG25]

In my notes, 42.5 grains of the flake powder gave the 218 grain bullet 2170 fps in a k98 and 2198fps is a M904/39 at -3C.

No offence, but maybe it is too much recoil from 45 grains.

 

[Maple57]

I had a Mauser in 308 that shot badly. One day I slugged the bore and found it was over size.

Then I started loading 7.62x39 rounds into a 308 case and it became a tack driver.

Strange war time oddities I suppose.

 

[Volhv]

I decided to develop a load around the 45 grain powedr charge, because 45 chronographed at 2200 fps a couple years ago when I first started playing with this stuff. I' ve gone as high 46 but didn't chronograph it. You're right, I should use it more often. Velocity spread between the rounds would be some good data to have. 46 grains, and a bunch of other loads between 45 and 46 shot about 3 inches. They were consistently all over the place withing the 3 inches, unlike the targets that I've posted that appear to have the potential for a lot better.

The 98 mauser rifles I have are military, and they all have very long throats. Even these long bullets would need to be outside their cases in order to touch the lands. No helping it in that department. I wonder what one of those lothar walther military contoured barrels is like...

I will chronograph subsequent loads and set an upper threshold of about 2300 fps. We shall see if things tighten up.
Will have to check the stock for barrel contact, and adjust as required.

I fired off 3 rounds of 1955 west german surplus 197 grain. Those printed a group of 1.3 inches with two holes touching. With only 3 rounds that might not mean anything, but it gave me hope.

No offense taken on the potential for flinching. That could always be a possibility. I find these loads to be milder than those 200 grain at 2500 fps techrim rebuilt rounds that were floating around a few years ago. So many potential variables. Worn out barrel, crappy shooter, I'll fitting stock, bad handloads, inconsistent positioning of rifle on front rest.... some things you just can't help, so you just have to adjust the others and hope for better results. I'll try and track down some factory ammo, and see how that does. I used to get s&b for a reasonable price years ago.

 

[Volhv]

The two groups had a powder charge of 46.8 and 47

Bore condition

Chronograph results

46.4 grains
2220 fps
2271 fps
2205 fps
2292 fps
2177 fps
Average 2233


46.6 grains
2256 fps
2250 fps
2255 fps
2243 fps
2262 fps
Average 2253


46.8 grains
2290 fps
2268 fps
2279 fps
2216 fps
2293 fps
Average 2269


47 grains
2273 fps
2257 fps
2247 fps
2324 fps
2264 fps
Average 2273


My 308 grouped a heck of a lot better with a load of 43 grains of the sewdish flake and some 150 grains ppu flat based bullets. That's probably a pretty mild load that I did not chronograph. I only had a hand full of bullets that I just wanted to burn.

I will be working up a load for 165 grain bullets for the 308.
44 grains was a bit slow and grouped poorly with a 5 shot average of 2525 fps

 

[Andy]

Great work! Only a tiny number of members would go to the trouble you have to follow a systematic process to get the most out of an obsolete powder.

You had quite a spread of MV's at 46.4 grs, but the other loads were quite good. I think that at 47.0 grs in your gun, you're approaching 50K psi, and so you're getting close to a Max Load.

Your groups continue to get better, but you still have a flyer in every group. Have you kept track of which shot (#1-5) it is that's the flyer?

That said, I'd say the flyers are not related to the load, so if that's true, you've narrowed it down to rifle (and rest) and shooter.

The bore doesn't look too bad, and I have bores no better that shoot well. Have you tried other powders with that bullet? Maybe your rifle doesn't like that bullet..........

 

[bigedp51]

After looking at your bore photo I would recommend foam bore cleaner. It will remove the carbon and copper with no scrubbing.

Below one shot of foam bore cleaner and left to soak overnight. This barrel was pitted and frosted and would "eat" copper bore brushes and give false copper readings.

Below a AR15 with foam bore cleaner, the blue is copper and the black is the carbon.

Bottom line, I think if you used the foam bore cleaner a new bore photo would look much different.

 

[rgwhitman]

Similar experiences. The powder seems to be fine. I have got some good consistent groups in my 308 .. In my 8X57 and 8MM-06 using the 218gr. FMJ I would get good clusters with some flyers.
They ware not match grade bullets anyway and they will often get damaged during the pulling process. It is not always obvious but the lead core can get separated from the jacket material . This makes the bullets unstable. Still fun to shoot at the range though. Poor shooting is more apt to be a bullet issue than a rifle issue. I am finding in ten shots---seven good in a group, a small flier and often two further "stays ."

 

[Brutus]

If these Swedish bullet pulls are steel jacketed and you normally use copper jacketed perhaps just perhaps the differing jacket material is causing "irregular" fouling in your barrel.

Just one idea because I have zinc jacketed Calhoon varmint bullets. But on thier website it warns prospective users that before shooting your Calhoon hand loads your barrel has to be totally free of any copper jacket deposits.

just one shot in the dark

 

[Andy]

Have a look at this thread to see an analysis of these bullets:

https://www.canadiangunnutz.com/for...Swedish-8mm-surplus-ammo/page2?highlight=8X63

Here's a pic of some all cleaned up:



These bullets have a Lead Core with a Cupro-Nickel Steel-Clad (CNSC) Jacket. There were several types of 8X63 ammo produced, including an Armour Piercing round that had a Steel Core, but this is more of a "General Purpose" (m/32) ammo that sectioned appears as below.

For comparison, the closest commercial 8mm bullet I could find (at $0.80 each plus tax and shipping) is the 220 gr Sierra #2420 which I happen to have:

Sierra 8 MM (.323) 220 GR. SBT #2420

Dia. (inches)	Weight (grains)	Sectional Density	Ballistic Coefficients and Velocity Ranges
0.323	220	.301	.521 @ 2500 fps and above .524 between 2500 and 1850 fps .512 between 1850 and 1550 fps .495 @ 1550 fps and below