It was all going perfectly until...

[njc110381]

It's been an exciting day today. Got a note in the post to say that my 8x60R dies have arrived from America, so off I went to the post office to pay the fees and pick up my long awaited kit.

 

I got home and set them up. All looked good and the 9.3x74R brass that I managed to pick up forms down lovely. A quick run through the seating die with the seater plug removed completed the first stage, then it was off out to the shed to hacksaw the 74mm odd looking cases down to about 62mm. I then came in and finished them down to 60mm with a case trimmer before doing the final resize to bump the shoulder back a little further and complete the neck - another quick trim and they were done.

 

As I wasn't too confident in the whole process I tried a primed case in the gun. Nobody is sure whether the rifle has even been fired, and it certainly hasn't for the last 50 years. It's setting off primers nicely though so all is well.

 

Next step was to create my dummy round to check the dies with each time I set them up. So I seated a bullet and tried it in the gun. It wouldn't completely chamber so I shoved the bullet in a bit more - no change! Closer inspection after ramming it home and then back out with a cleaning rod shows some marks where the neck of the case is jamming in the chamber... So now I need to neck turn! Sod it! It was all going so well but hey - it's a simple fix and at least the cases are sizing down easily with no signs of splitting. It's not actually working the brass too much which is great.

 

Here's a picture of the various stages of case. A 9.3x74R as standard, then partly formed ready to be cut with the hacksaw, a completed case that has been knocked back further and trimmed/deburred and then last but not least the dummy. Considering the effort that I've had to put in to other custom calibres this one is turning out to be fairly simple. Perfect!

 

Edited July 31, 2013 by njc110381

[Imperfection]

8x60r..!

 

Thats beyond obsolete! I thought i shot old calibres.

[njc110381]

It's not the Kropatschek, rather the 8x57 rimmed Mauser reamed out which was created to get around the military calibre ban temporarily imposed on Germany after the war. I'm pretty sure mine was made in May 1943.

 

The next question on this round is what energy I could expect to get from it using cast loads? It apparenly runs at between .30-06 and .300 magnum performance with bullets up to 275gr, so 1700ft-lbs should be possible?

[Imperfection]

If i play about with the mix i can push cast 357's approximately 1300fps with no sign of leading so provided you use a gas check and the lead is hard enough you should be able to easily exceed this. Powder wise,something slow burning for larger calibres like Alliant reloder 15 maybe?

[Underdog]

Of course it will gross more than the mystical magic figure of 1700 matey ......excellent report..been waiting.

Actually I wondered about brass thickness...I know some mauser brass is thinner than more modern American chamberings but a long 9,3mm! In saying that is more to do with the 74mm being shortened to the thicker brass?

 

U.

[njc110381]

I think that's the main cause. I'm pulling in around 12mm of case down to 8mm - the necks are pretty thick.

 

I did have a thought last night which had me running up the stairs to check - most of my cases are S&B but the dummy was loaded in RWS, which was visibly thicker. I just had to do a dummy S&B because I was certain that would fit, but no! Hey ho.

 

Now I need to find a decent case neck turning tool for not too much money. I may try to do a few on the lathe but I have no idea how that will go! I'll have a play with some .308 range brass and see how I get on before trying my limited supply.

[rem708]

Lathe turning should work just fine. Make a mandril to fit into the end of the case that is a snug but loose fit and lube it (held in your head stock). That way the case won't wobble. You can cut into the shoulder just a little but its best done on cases after they have been fired in the target chamber.

 

If brass is that rare then I would suggest you anneal the case necks. I frequently reform brass just 0.6mm and it does work harden. On military brass this is a good thing as it tends to be thicker and softer to start with. On commercial, however, it causes premature splitting.

 

Tight necks are not a good thing as it causes a very rapid rise in case pressure and hence very high pressures on the bolt face. If you have a means to check neck thickness (specialised micrometer or even a tool specifically for this job) then use it. I had a few close shaves when I started this process! Don't try and get it spot on the first time. Fine tune with residual case tension after firing the first time. If you wants some practical hints on how to get this right without loads of specialist tools let me know.

 

I note in your picture you have a bullet with a cannelure. Don't crimp unless you REALY REALY need to. If your neck tension is correct that is all you need. Crimping only causes work hardening of the very tip of the case and that is where splits start.

 

I personally love making wild cat brass. Its just amazing to think you can remould solid brass that easily.

[casts_by_fly]

I need one of these. This is almost exactly what I've had in the back of my head for a while. My encore loves rimmed cases, and encores are easy to do custom chambers with. I have been thinking about a rimmed 9.3x ~70mm as a big thumper kinda gun that would be a bear stopper. I thought about 9.3x74R straight as you started from but it is a fairly low pressure round for blackpowder orignally. I thought about a 9.3x62R with custom brass and that is basically what you've done. I like it. Loaded up, I bet a 250g round at 2500-2600 would be more than doable and should have some real thumping power without being too horrible on the shoulder.

 

thanks

rick

[rem708]

I need one of these. This is almost exactly what I've had in the back of my head for a while. My encore loves rimmed cases, and encores are easy to do custom chambers with. I have been thinking about a rimmed 9.3x ~70mm as a big thumper kinda gun that would be a bear stopper. I thought about 9.3x74R straight as you started from but it is a fairly low pressure round for blackpowder orignally. I thought about a 9.3x62R with custom brass and that is basically what you've done. I like it. Loaded up, I bet a 250g round at 2500-2600 would be more than doable and should have some real thumping power without being too horrible on the shoulder.

 

thanks

rick

If you want a 'thumper' then try a Ruger No1 in 45-70 with a 500gn bullet. I was allowed to shoot one of these when I first started shooting (many many moons ago in the USA) and was NOT allowed to shoot prone on the fear it might do me some harm. From a kneeling position I hit a piece of tube used as a bell for long distance. It was approx 1/2 inch thick and about 8 inch in diameter. Once retrieved (after it spun off some distance) we found a hole about 3/4 punched through it. Good job one of the senior range officers with me at the time as he had to explain to the club this new peep hole

 

Apparently the action is so strong that in one reported case the brass largely disappeared after an abusive overload and yet the action survived.

Edited August 1, 2013 by rem708

[Underdog]

Yes sir...45-70 has three levels of reloading tables. The highest being for Ruger #1 and a large Mauser .

I love the old round and even at the lower bp level loads is a fine option IMO.

 

U.

[rem708]

Kicked like a mule

[casts_by_fly]

I've consdered the 45-70 and its relatives (45-90, 45-120) plus the 444 marlin and similar. To be honest, I don't like cartridges without a shoulder. They just look odd to me. That's why the straight 9.3x74R wasn't doing it since it looks basically straight walled. I will agree that the 45-70 is a thumper. Maybe just a bit much of a thumper.

 

thanks

rick