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Old December 25, 2011, 04:12 PM   #1
johnm1
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8x50R Austrian

I have a little time before loading for this rifle and I am just starting my research. The rifle is a Steyr M95 long rifle and for now lets assume it is in the original 8x50R caliber. Confirming the chambering is one of the reasons I have a little time. I'll be doing a chamber cast just to be sure. The barrel markings are not quite as definitive as I would like as the Czech property mark was struck directly over th Austrian proof marks. There is no large S on the barrel though the Czech property mark starts in an S (small).

Brass
Brass being the first issue to overcome. I see that there is 7.62.54R reformed to 8x50R dimensions available. I would think that resizing 8x56R brass (cut and resize) would be simpler than using the reformed Russian brass or resizing it myself. Cost is an issue here as the price on reformed Russian brass is $1.32/case. The cost of empty 8x56R brass is a more realistic $0.40/case

1. Can I resize the 8x56R to 8x50R fairly easily? Can I use the 8x50R sizing die to reform the case?

Bullet Size
The original caliber used a .323/324 bullet but the base expanded to fill the bore diameter of .329/.330. The 8x56R chambering uses a .329 spitzer bullet in the same bore. Using prudent reloading practice, is there any reason, other than bullet availability, not to use the .329 bullets and a reduced 8x56R load to start. My thoughts here are that any modern .323 bullet will allow gas to escape past the bullet. And as long as the .329 bullet is a boat tail, with less surface area in contact with the lands/grooves, it should be safe. My assumption here, and I believe the specifications for the M95/30 rifle confirms this, is that the bore diameter was not changed when the rifles were re-chambered from 8x50R to 8x56R. The chamber had to be reamed longer but I can't imagine that the barrel was rebored/rifled.

2. Do you see any issues working up a load for the 8x50R from the 8x56R data (starting low) and using a .329 bullet?

Thanks
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Old December 25, 2011, 05:57 PM   #2
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There are two 8×50 R and two 8×56R cartridges. One of the latter, which is known by three names, the 8×56R Mannlicher M.30S or 8×56R Solothurn or 8×56R Hungarian Mannlicher, is convertible to the 8×50R Mannlicher M93 cartridge. The 8×56R M89 Portuguese Kropatschek short cannot be converted as the rim and base are too wide, and the 8×50R Rival/Minard (also called the 8×52 SR) is too narrow for either 8×56R at the base to be involved in the conversions in any convenient way.

In the case of the possible conversion, simply running the 56 mm case into the sizing die meant for the 50 mm case may do the job with enough good lube. You will then want to final trim and inside ream the neck or to run an inside mandrel in then outside turn the neck to remove any uneven brass thickness.
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Old December 25, 2011, 08:29 PM   #3
johnm1
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Nick,

You always seem to answer my questions. Hope the holiday season has been good to you and your family.

I figured the common 8x56R used in the plentiful M95 carbines would size down to the 8x50. I am a little concerned with rebound but the sizing die is another $90 and if I can avoid that cost I would prefer to do so. In the end, if I need the sizing die I will get it.

This is an odd little cartridge. The original 8x50R bullet diameter was 3.23/24 and the bottom of the grooves in the barrel were cut to 3.30. The bullet design of the day had the bullet riding the lands and the base was designed to expand to seal the bore. The newer 8x56R was designed with a .329 boat tail as I figure the newer spitzer bullets base would not expand to seal the bore. A shorter lighter bullet with a boat tail design would have less contact area, relatively, in the barrel and a load was finally designed for it. From what I read on the internet the 8x56R round carries quite a punch so I figure the receiver is pretty stout.

There is some conversation on the internet about developing loads for the 8x50R and I am still reading them. I don't need a full house round for this rifle. I just want to have something to shoot informally and take to at least one match. Although I have been reloading for close to 30 years (big break when the kids were young) I only started loading for rifles early this year. It appears that a cast bullet is probably the wisest bullet selection but I have never loaded for a cast bullet with a gas check. I have this underlying fear that I'll leave a gas check in the barrel. I suppose I can learn more about loading cast bullets for a rifle and address my concerns.

That being said I want to start with a load using a .329/.330 jacketed bullet like the 8x56R does. Something with a round profile to reproduce the original dimensions of a loaded cartridge as closely as possible. This will be to aid in feeding as I understand that when the caliber was changed to 8x56R on these rifles/carbins the magazine was altered slightly to change the angle the cartridges left the magazine. Velcity is not important other than to try to get something that will utilize the sighting system on the rifle. I figure if I start low enough I should be able to avoid catastrophe. One concern is the actual chamber dimension where the neck of the case rests. Being it was originally machined for a bullet of .323/24, a bullet of .329/.330 may not chamber. Again, when these rifles/carbines was rechambered I understand a step was machined into the chamber at that location to allow for the larger diameter bullet. I can test this during load development. There is some pretty interesting reading on Yesterday's Weapons Forum by gschwertley on this cartridge.

So the real question is can I safely develop a load using the .329/.330 bullets?
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Old December 26, 2011, 03:09 PM   #4
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Sounds like an interesting project. You will probably want to do a chamber cast or hammer a soft lead slug into it to get the actual throat dimensions and location. It may change your mind about those long protruding round nose bullets in groove diameter, though you can, of course, cast a bore riding nose design bullet that fits. NEI's catalog shows their #98 mold is a gas checked 245 grain, .330" bullet bore riding nose design of close to that shape, though it has a fairly wide flat meplat, which should be good for terminal ballistics. You'd have to call them to ask what the diameter of the nose actually is, though.

As to gas checks, if they were going to stick in a bore, I expect someone else would have had that happen by now. The reason they don't is the propellant gas pushes on the check, while the check is what then pushes the bullet. So, if the former isn't being pushed out of the tube, the latter isn't either. There are problems with the old style smooth-sided gas checks coming off after the bullet clears the muzzle and tumbling into chronographs or putting extra holes in close targets, but the crimp-on style won't.
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Old December 26, 2011, 04:27 PM   #5
johnm1
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Nick,

Keep in mind that I am a long time pistol reloader but only started reloading for rifles this year. There were stories of handloaded half jacket pistol bullets that were mis-loaded with enough momentum to eject the lead but leave the jacket in the barrel for future diaster. I never said my fears/concerns were valid, only that I had them. What concerns me most about this project is there isn't a lot of published data for either chambering. I am comfortable working within the ranges of published data. Working up from scratch is another story though.

That bullet sounds interesting. With as much as I have going on I really don't have any desire to start casting my own lead bullets. Maybe I could purchase the mold for one of the local bullet casters and have him cast them for me. I'll call the manufacturer after my chamber cast is made. And it looks like I'll be doing that myself. My gunsmith is good but I was given an estimate of a month to do a chamber cast. I Have one other source that could do it for me but I am not hopeful.

Thanks.
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Old December 26, 2011, 05:03 PM   #6
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John,

The only time I've heard of jackets being left behind in a barrel are when they were blown out through the bottom. However, it is a theoretical possibility with a very light catsneeze load of pistol powder, for the pressure to bleed out around the case, letting the bullet slow so inertia pulls the lead from the jacket. I've not witnessed it personally, though and I've seen my dad fire a lot 100 grain half jacket plinkers in his '03 Springfield over just 5 grains of Bullseye. The half jackets aren't bonded to the cores, but by comparison the gas checks made commercially these days are all crimped onto the bullet, so separating them would be more difficult.

QuickLOAD should be able to make a powder choice and useful load range estimates for you once you know your bullet weight and length and seating depth and know the capacity of the formed cases.

Nick
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Last edited by Unclenick; December 26, 2011 at 05:13 PM.
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