Strange behaviour with 8X57mm handloads

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I've recently started handloading for a new-to-me rifle - what I believe is a Husqvarna 648 (8x57mm). I loaded some 150 gr Speer Hot-core bullets with BL-C(2) from 51 gr to 54 gr. Nothing remarkable occurred and no load really stood out in terms of accuracy.
I also decided to load the Hornady 195 gr Interlock bullets with H4350 because I've had good luck with this powder in my 30-06 and some other calibres. The Hodgdon site says that the load range for 200 gr bullets is 49 gr to 54 gr, with 54 gr being compressed. I seated my bullets out almost to the lands (COL of 3.10"), which is considerably longer than the COL listed on the Hodgdon site. Even so, my start loads of 49 gr leave no room for the powder to move around at all, and by about 50 gr (if not 49.5), my loads are compressed. I went up to 52.5 gr and the powder was too compressed for my liking so I stopped there. I fired some of these loads the other day in sub 0 °C temperatures. The first couple of groups were pretty routine. I don't have a chronograph, so I can't measure velocity. But I noticed something weird with the elevation. I was shooting at 100 yards, and here's what happened with the elevation: 49.0 gr (-0.25"), 49.5 gr (+1.0"), 50.0 gr (+1.75"), 50.5 gr (+5.5"). This sudden jump in elevation was alarming to me, so I didn't shoot the remainder of the groups. At the time, I also looked at the brass cases, and it seemed that there was a bit of a bulge where the case wall joins the web. The primers looked perfectly fine though. When I got home I measured the diameter of where this bulge is, and according to Ken Waters' Pet Loads, the diameter was nothing to be alarmed over (0.470"). Some of my other cases look similar, even with lighter loads and with the loads using the 150 gr bullets.
I have not slugged the bore, but the barrel is marked "Kal 8mm" and I measured the groove diameter with my calipers, and it measures 0.323", so I am pretty confident that the barrel is not one of the smaller diameter barrels.

Is this sudden jump in elevation (velocity) something to worry about, or am I just being paranoid? Has anyone used H4350 with heavier bullets? Did you notice something similar?
 
Bullet impact being higher is not necessarily directly proportional to the change in velocity. In fact, sometimes higher velocity loads hit lower, or to the right or left, since they exit the muzzle at different stages of the barrel's vibration.

This has been easily demonstrated many times.

Ted
 
Nothing to be alarmed with. I've taken imr 4350 to 52.5 grains with a 200gr bullet and velocity was just shy of 2500fps. Accuracy was about 1 inch. I've had better experience with 4895, 4064, 3031 taking them to 2550-2600fps with sub moa accuracy. My personal load for my main hunting rifle is 46.5 gr 3031 with 196gr Norma dual core plastic point for 2550fps and half inch group.
 
Try a drop tube like they would use for black powder, the powder will settle better into the case, at least that is what I have been told.

I am sure you could use a big straw as a drop tube to test it.

I just took a couple rifles out for load testing, higher and lower velocity, different bullet profiles, no defined reason for the bullet impact except to say that they hit different spots in all cases.
 
Heavier bullets tend to shoot higher then lighter ones. You are also probably seeing some stringing as the barrel warms up due to contact with the stock.
 
I doubt you could get enough 4350 into that case to cause a problem.

Two things came to mind as I read your post.

1) Is the powder contaminated? Pull some of the ones you brought home and check for grains that look different.

2) Scale calibration. Are you loading 5 grains more than you intended?


Shooting higher is not indicative of anything related to the pressure of the load. It just means it is shooting higher, probably related to the barrel.
 
I have a Husky 8x57, a 98 action, and light loads shoot a bunch lower than I had expected. Already mentioned is barrel vibration and such, and without actual chrono readings, I can't offer an explanation. It does seem like your pressures are rising. BTW, I also abandoned BLC-2, OK but somewhat lackluster. I was able to get a 150 to shoot well, but if you read articles, not common to get a light bullet to shoot well in a 8x57.

A small point, most 8x57 rifles are surplus, and having bullets even close to the lands isn't a possibility. My Husky appeared unfired, I wasn't able to seat my bullets to the book setting as the bullets were hard into the lands. I only had Prvi brass, and it is not up to handling top pressures. It will bulge the PRE area fairly easily.

The Hornady 195 is listed at a OAL of 2.994 in #10. In your rifle that would be app 0.100" off the lands, perfect for a secant ogive bullet for hunting.

My first criteria for OAL is that the case neck fully contacts the bullet shank, next is that it fits in the magazine, and last is that it is not touching the lands. Fooling with OAL comes later, to fine tune the load. I only have a receiver sight on my Husky, fine tuning a load is somewhat difficult.

You left off a few details, like the make of the case, primer, and the PRE of factory ammunition fired in your rifle. My normal PRE was 0.4690, every chamber is slightly different.

Sometimes funky stuff happens, obvious enough that it's noticeable, and we stop to ponder the happenstance. The prudent next step would be to change directions, abandon the recipe. I view it a subtle warning, a tap on the shoulder.

When I worked up loads for my 8x57 and 200 gr bullets, I tried Varget. It wasn't much of a work up actually, I just used a load from a magazine, from Handloader #282, February 2013, Mike Venturino, and it worked well enough that I didn't do much more development.

I like and use the 4350 powders, IMR4350, H4350 and IMR4451. They're good, but IMHO, a bit slow for the case capacity and expansion ratio of the 8x57. Nosler did get good velocity in a comprssed load or 52 gr. and an OAL of 3.030". I'm not a huge fan of compressed loads, except in certain instances. Using a drop tube to gain capacity is OK, and it allows you to seat a bullet without compressing the charge. If I use compressed powder loads, I usually switch to a F215 primer, to my way of thinking, when the powder is compressed the primer has to work harder to blast fire through the powder charge.

All the best, I'm a fan of the 8mm Mauser.
 
I have a Husqvarna Commercial Mauser actioned 8x57, and I get stellar
performance out of it with the 195/196/198 grain bullets, using VV N550
Great velocities at acceptable pressures, and accuracy is also very
acceptable. Dave.
 
The powder is not contaminated. Even if it was, it would be contaminated in every load, which I don't believe would explain the sudden increase in elevation for an increase of only 0.5 grains.
I suppose I could pull a bullet and double check the weight of powder. I used a beam scale, so it's relatively easy to be 5 grains higher than intended if you're not paying attention. That being said, I don't think 55.5 grains of H4350 would even fit in the case, let alone 57.5 (52.5 is where I stopped).

I see that most people don't think a sudden jump of 3.75" for 0.5 gr increase in powder is anything to worry about, but whenever I have worked up loads in the past, there was always a relatively predictable increase in elevation with increased powder charges, which logically should be related to higher velocity. This is the first time I've seen such a huge jump for such a small increase. I guess the only thing that makes me a little more comfortable with trying the loads is the complete lack of stiffness in bolt lift and normal appearance of the brass and primer.
Ganderite said:
I doubt you could get enough 4350 into that case to cause a problem.

Two things came to mind as I read your post.

1) Is the powder contaminated? Pull some of the ones you brought home and check for grains that look different.

2) Scale calibration. Are you loading 5 grains more than you intended?


Shooting higher is not indicative of anything related to the pressure of the load. It just means it is shooting higher, probably related to the barrel.
Click to expand...
 
The loads were prepared with once fired Winchester brass obtained from factory rounds (by someone else). I'm using Winchester WLR primers. You'll have to help me out with what you mean by PRE. I've only fired maybe 4 or 5 factory rounds of PPU 8mm Mauser (196 gr), which I've heard is loaded pretty light, but I can measure those empties and compare them to the empties from the handloads in question.
nitro-express said:
I have a Husky 8x57, a 98 action, and light loads shoot a bunch lower than I had expected. Already mentioned is barrel vibration and such, and without actual chrono readings, I can't offer an explanation. It does seem like your pressures are rising. BTW, I also abandoned BLC-2, OK but somewhat lackluster. I was able to get a 150 to shoot well, but if you read articles, not common to get a light bullet to shoot well in a 8x57.

A small point, most 8x57 rifles are surplus, and having bullets even close to the lands isn't a possibility. My Husky appeared unfired, I wasn't able to seat my bullets to the book setting as the bullets were hard into the lands. I only had Prvi brass, and it is not up to handling top pressures. It will bulge the PRE area fairly easily.

The Hornady 195 is listed at a OAL of 2.994 in #10. In your rifle that would be app 0.100" off the lands, perfect for a secant ogive bullet for hunting.

My first criteria for OAL is that the case neck fully contacts the bullet shank, next is that it fits in the magazine, and last is that it is not touching the lands. Fooling with OAL comes later, to fine tune the load. I only have a receiver sight on my Husky, fine tuning a load is somewhat difficult.

You left off a few details, like the make of the case, primer, and the PRE of factory ammunition fired in your rifle. My normal PRE was 0.4690, every chamber is slightly different.

Sometimes funky stuff happens, obvious enough that it's noticeable, and we stop to ponder the happenstance. The prudent next step would be to change directions, abandon the recipe. I view it a subtle warning, a tap on the shoulder.

When I worked up loads for my 8x57 and 200 gr bullets, I tried Varget. It wasn't much of a work up actually, I just used a load from a magazine, from Handloader #282, February 2013, Mike Venturino, and it worked well enough that I didn't do much more development.

I like and use the 4350 powders, IMR4350, H4350 and IMR4451. They're good, but IMHO, a bit slow for the case capacity and expansion ratio of the 8x57. Nosler did get good velocity in a comprssed load or 52 gr. and an OAL of 3.030". I'm not a huge fan of compressed loads, except in certain instances. Using a drop tube to gain capacity is OK, and it allows you to seat a bullet without compressing the charge. If I use compressed powder loads, I usually switch to a F215 primer, to my way of thinking, when the powder is compressed the primer has to work harder to blast fire through the powder charge.

All the best, I'm a fan of the 8mm Mauser.
Click to expand...
 
I've got both IMR 3031 and IMR 4064. I've read that they are both good in this calibre. Maybe I will try them next. I haven't had much luck with them in my other calibres though, apart from my 30-30.
dgradinaru said:
Nothing to be alarmed with. I've taken imr 4350 to 52.5 grains with a 200gr bullet and velocity was just shy of 2500fps. Accuracy was about 1 inch. I've had better experience with 4895, 4064, 3031 taking them to 2550-2600fps with sub moa accuracy. My personal load for my main hunting rifle is 46.5 gr 3031 with 196gr Norma dual core plastic point for 2550fps and half inch group.
Click to expand...
 
You say that the bolt throw is normal and no signs of pressure, that feeling you are getting runs the show here. You have movement on your groups but differences in the vibration of the barrel will move around the group.
 
kamlooky said:
Perhaps a scope/mount/ring issue has developed?
Click to expand...

There's a small possibility that could be the cause. I had adjusted the windage just before the jump in elevation, and the scope is not a proven performer, but the 5 shots in the groups in question were consistently high. I'll double check the mounting.
 
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