Cast Bullets In 8mm Mauser

[wa4aqw]

After reading the very informative article by C. E. Harris (as posted by rebertbank) I have tried to use cast bullets in my 8mm Mauser rifles, a Turkish Mauser and a Yugo M48. Both of these rifles perform reasonably well using surplus ammo, but the lower cost of cast bullets is very attractive.

I used a Lee C324-175-1R bullet, gas check, Lee liquid alox, and sized to .323. The charge is Harris’ universal load…16 gr. of 2400 powder. This combination seems to perform reasonably well at 100 yards, but I have encountered two problems.

First, there seems to be an excessive amount of gas blowback which can be felt on my face and seen by the powder residue flowing back from the mouth of the fires case. I do not experience this gas blowback when using cartridges loaded with FMJ bullets. Is the 16 gr. powder charge to small in that the case neck and mouth are not sealing within the chamber, or what is causing the blowback?

Second, the 2400 powder seems to be excessively dirty. There is a cloud of smoke when the round is fired and a large amount of residue is left in the chamber, bolt, and surrounding parts. Is there a similar powder that could be substituted for 2400 that is cleaner burning yet produce the same results?

Any ideas or suggestions which might help resolve these problems would be very much appreciated.

[Ricochet]

Yes, it's blowback. FWIW, you'll get that if you use the steel cased Romanian military export ammo that's been widely marketed the last few years (but seems to have now dried up.) The blowback doesn't hurt anything, but if it bothers you, you might try things like using neck sized cases sorted to the gun for better sealing. A faster burning powder (like the Red Dot "The Load") might work. Personally I load all my 8mm cast boolits over near case-filling loads of IMR 7383 and have never had any blowback. It's a dirty powder, as is 2400. Dirt doesn't concern me, it cleans out.

[sundog]

I can sure agree with the neck sizing, especially with a Lee collet. Size your boolits bigger, as big as you can get them and still load. While that Lee 175 is okay, I much prefer the Karabiner (custom but available from MidSouth I think) thru a .325 loobsizer. Bigger, heavier, more powder in the 4227 to 4895 range, seated out as far as possible.

[GrizzLeeBear]

You can go up on the powder charge too. 16 grains is just where Harris found good accuracy with all the military calibers. You can work your way up, say a grain at a time until the sooty necks go away. Might only take a grain or two. If it maintains accuracy, then your there. This is what I plan on doing for my new Yugo 24/47 when my mold arrives.
The cloud of smoke may also be from the lube, not just the powder.

[9.3X62AL]

+1 to all the above--and WELCOME ABOARD!

The Lee 175 grainer shoots VERY well from my G98/40 whose bore has seen better days. I size @ .325" and lube with Javelina Alox. If the stars align properly--and both Glen and Buckshot have poor range days--I can threaten to conquer on Burrito Shoot days. Not the fault of the load at all (16.0-18.0 x 2400), but the operator is always subject to variation--putting it delicately.

16.0 grains of 2400 does some "burn-back" on my cases, which is reduced markedly at 17.0 grains and disappears at 18.0 grains. Accuracy remains constant throughout, trajectory rises a bit with each increment. Once the sights and bore line are speaking the same language, I can ring the 200 meter dinger plate pretty consistently with this boolit and the loads described herein. The range near my new place goes out to 600 yards, so you just KNOW the 8mm will get at least a test-drive at distance soon.

[wa4aqw]

Here’s some more background information I should have included in the original post. The cases are W-W Super sized full length using RCBS X-Dies. Bullets had gas checks and were seated without any crimp. Primers are Winchester WLR.

I suspect the blow-back problem is caused by not enough pressure in the 16 gr. charge to cause the mouth and neck of the case not to fully seal when fired since there was almost no resistance when the fired cases went through the sizer die. I will load some test cartridges using 17 gr. and then 18 gr. of 2400 powder to see what change the increased load will make in both blow-back and accuracy. I will also load some cartridges with a starting charge of 20 gr. of IMR 4227 for comparison. When these rounds are fired I will use the chrony to get a velocity measurement. The results will be posted later in this thread in hopes they will be of benefit to someone.

For many years I have been loading cast bullets in handgun cartridges but this is my first experience with cast bullets in old military rifles. Quite obviously, it’s not the same ballgame. Again, thanks for the posts and guidance.

[Buckshot]

.................wa4aqw, welcome to the board. Smokless needs pressure to burn cleanly so anytime you see what you did, you need to do something to increase pressure. Drop back to a faster powder, carefully increase your current charge, confirm your caseneck grip, add a crimp, seat the slug to engrave, or use a heavier slug.

The 8x57 is a great cast boolit cartridge and generally an eager shooter if it's in any kind of condition. A real shame there aren't more 8mm cast designs out there.

Please be sure to let us know how you do.

..............Buckshot

[jonk]

Any of my 8mms with bores even decent will shoot cast great if you find the right load.

I've gone up to 23 gr of 2400 with this mold no problem.

I suspect you will solve your obduration problem in the 18 or 19 grain range.

Right now my favorite is 17 gr of SR 4759 but have done well with that, Red Dot, Bullseye (for really light loads at 50 yards especially) 4895, 4756, WC 820, well... it's hard to find a powder that doesn't do at least ok I find with this mold in 8mms.

For what it is worth I seat right to the lands for light loads or just off for higher power ones.

[dromia]

Welcome to these forums wa4apw.

Ditto all that has been said.

How much boolit retention have you got? I find Winchester cases to be pretty thin walled, therefore not giving too tight a grip on the boolit.

So as well as going with as large a diameter boolit as you can cast some thicker walled cases could help as well.

[mike in co]

just to re-enforce what has been said:

first size larger...more like 325...323 is a jacket dia, not a cast dia.

second neck size only. no need to full length size esp with cast loads......( just set up one lot fot each rifle). get a lyman m die or very slight flare on the neck...just big enough to start the boolit...do not get carried away....


start bumping the powder up a little at a time...try 4227.


fun guns to shoot...


mike in co

[Ricochet]

If you neck size and have more than one rifle for the same cartridge, you'll most likely have to segregate the cases for each individual rifle. That would be the thing to do for best accuracy, but I don't want to go to the trouble for my assorted Mausers and Mosins, so I full length size to a size that will go in the tightest chamber. Shortens case life, of course. I also take that approach for seating depth, to accommodate the tightest, shortest throat. Just got a rude surprise when I found that my loads that work very well in all my Mosins wouldn't even come close to chambering in my new PSL.

[leadeye]

8mm surplus is getting harder to find at a good price. I am almost out of my old supply of berdan ammo. What is the collective opinion on the Saeco #81 8mm for say a 98K?

[bcp477]

I never got good results in my M48 with powders such as 2400, or really fast powders like Unique, for that matter. The ubiquitous 16 grains of 2400 was no good in my rifle at all. Greater charges of powders like 2400 only made things worse. In my particular experience, I had to switch to a good bit slower powder, such as IMR-3031, before I began to see acceptable results. Every rifle is different, however. I mention this only to illustrate that fact - you may or may not get the results you want with the "traditional" (fairly fast) cast bullet powders. As for the "dirty" and smelly aspect of 2400 - I had the same experience. Now, I only use the slower powders, such as 3031 (or 4064)....with a bit of cotton wool filler (and I get no "blowback"). This works fine for me, in any case, because I now shoot only paper-patched bullets at upwards of 1800 - 2000 fps.

Just FYI....in case it helps.

[Maven]

wa4.... I have a Shaw rebarreled milsurp 8mm Mau. that shoots the Lee CB quite well when sized to .324", with NO blowback ever and never with 2400 (i.e., I haven'tused 2400 in the 8mm Mau.). You may want to try H/IMR 4198 or another powder of similar burning rate, but starting at 24grs. and working up to 27grs. Milsurp WC 820 is a bit faster, but also an excellent choice in doses of 18.5grs. -> 21.5grs. as is the much slower WC 860 (48grs. + mag. primer). If it's your only 8mm Mau., I'd also recommend neck sizing your brass or at least partially full-length sizing it: Back out your FL die enough so that it leaves ~1/16" of the neck unsized [to enable the loaded round to be centered in the chamber].

[GrizzLeeBear]

Maven, what kind of recoil and velocity do you get with the 48 gr. of 860? I have heard 860 is a bit dirty too. Could you shoot 50 rounds without the gun starting to "jamb up" with fouling?

[Maven]

GLB, Recoil is moderate since part of it is due to the weight of the powder itself, but it is largely absorbed by my rifle (weighs 11 lbs.). As for WC 860's cleanliness, you're right, there's a lot of unburned powder left behind and it must be removed after every 5 - 10 shots to prevent powder dented cases and unburned powder in the locking lug recesses. Btw, some of the bore guides made for a particular action can be used as a blow tube of sorts thus saving you the trouble of frequently dry patching the bbl. Keep in mind that we use 860 with CB's for reasons of economy, not because it's the best powder available and as such, we tolerate the filth and inconvenience of using it in low pressure applications.

[Newtire]

Another bit of agreement about the powder charge needing to be increased slightly. I used the 17-18 gr. range of 2400 or 21-22 gr. SR 4759 or 12 grains of good old Unique. I get great results with the Lee 175 sized to .325".

I have been making my cases from .30-06 military brass and found they got a tad brittle from all the forming and maybe brass being old-Lake City 67-68. I had a high percentage of split necks until I annealed the brass.

I love the 8mm. Just wish there were more variety of moulds.

[GrizzLeeBear]

I have been making my cases from .30-06 military brass and found they got a tad brittle from all the forming and maybe brass being old-Lake City 67-68. I had a high percentage of split necks until I annealed the brass.

I've only formed 50 of them from LC 30-06 brass so far. I annealed the necks of the 06 brass before trimming and resizing. Along with preventing split necks, I think it makes it easier to push the shoulder back as well.
Since I only have the regular (RCBS) dies I have found that it is easier to size the brass without the expander/decapper first. Then cut the brass off a little long with a dremmel. Then lube the neck and run through the die with the expander/decapper. Then trim to length and chamfer/deburr.
When I cut the brass off first and then resize/expand neck in one step I found a small problem. I lube the inside of the 06 brass, but when you push the shoulder back you now have the unlubed portion of 8mm neck that used to be 06 body. this made it hard to pull the expander back out. My new Redding file trim die should be here today from Midway to solve this problem. Should speed up the process a little bit.

[Newtire]

Those are some great tips Grizz. I'm about set to make up a mess more of those 8mm cases. I was just eyeballing the case and cutting it off close with a hacksaw while mounted in the trimmer. Every once in awhile I would cut one short.

I think I wil try the annealing before the forming this time. Maybe will make it easier to cut too.

I ordered an 8mm M-die from Lyman a couple of months ago but finally cancelled order as they are still on backorder. Maybe will get a friend of mine to make me one on his mini-lathe.

I have the Lee universal case mouth expander but the M-Die seems to make the necks all come out straight when I put the boolit in instead of looking like a snake that has just swallowed a frog.

[GrizzLeeBear]

Tried out the Redding trim die. Works pretty good for the first step. Just run it all the way down to the shell holder. Run the 06 brass up and cut off with a hack saw. The top of this die is REALLY hard, the hack saw doesn't put a mark on it. The Redding die is sized like a rifle chamber (and a generous one at that), not like the FL size die. Final sizing and pushing back the shoulder a little to its final position takes place in the FL size die (along with expanding the neck to 8mm). For $22 its a good deal for making it easier to start sizing and accurately cutting off the brass.