Australian .303 Wildcats

[22hornet]

Paul,
 
Thanks for your input.
 
Thats a pretty low chamber pressure for such speeds, what if it was bumped up to the standard pressure limit for a 220 Swift, what speed then?
 
Also, I do remember reading about the Martini action being able to handle pressures well in excess of most bolt actions. I don't know for sure but I have been told that the surface area on the Martini action is much larger than the area on the locking lugs on a bolt action rifle.
Can anyone confirm this?
 
The ejection system is the weak link in the Martini action, maybe this was why the "long lever" was introduced?

[kombi1976]

There are issues with the Martini Henry action.
Firstly, the breech block is a cast item designed with the pressures of a black powder cartridge in mind.
Admittedly the Martini Enfield, the .303 Brit adaptation of the large frame single shot, has either a steel breech block or breech block face but that is no great plus in way we would view it today.
The steel made around the turn of the 20th Century was for the most part astoundingly inferior compared to modern steels.
It's good, don't get me wrong, and Paul Mauser designed a rifle around what could be done with variable hardening steel.
But even that isn't the end.
Unlike a Farquharson or Ruger No1 action the block does not slide up and down, it pivots on a hinge pin and most of these are probably around 100 years old......or more.
The receivers are also DEFINITELY over 100 years old, many more than 120 years old.
So what you are suggesting is like shoehorning a modern high performance small capacity 4 stroke motorcycle engine into a bicycle design and made in the 1880s.
The design may be good and there may be safe operating levels but it was not designed for the things you suggest.
Get a P14 if you want to wind up the boost on a 303 based wildcat.
And yes, the extractor on Martinis is the biggest weak link.
Don't get me wrong.....I love Martinis, but after thinking on it I decided NOT to have the Martini Enfield action I have made into a dangerous game rifle.
If the rifle heats up it doesn't like letting go of the case.
I have 2 Cadets like this and one regularly needs firm encouragement to eject cases.
The advantage of the 303 Wildcats was always to wring as much out of as possible in a SMLE and therefore have a more flexible rifle with a fast cycling action.
It was only after WW2 that they began to try them in Mausers and really wind up the pressure.

[gitano]

Kombi,
 
All of what you say may be exactly what is written about the Martini-Enfield... but, it is not consistent with my personal experience with, what is albeit only one, receiver. Nonetheless, my receiver was made in 1878 making it 136 years old. In ignorance, I pushed the .22/.30-30 to pressures in excess of 63,000 PSI and that old action didn't even whimper. I've read all about the "weakeness" of the tilting block (Martini) as compared to the falling block (Farquharsens). These "engineering" exercises always sound good "on paper", but in practice, I've yet to hear of one of these actions actually 'giving out'. As for ejecting, neither the hot-rodded .22 nor the .50 Alaskan have shown the slightest tendencies toward ejection issues. Of course the max pressure I've put to the action with the .50 is about 25K PSI, and it won't get anything more.
 
None of which do I say to support the idea of hot-rodding an M-E or even a SMLE. I don't care for hot-rodding rifles. Just doesn't make sense in the long run. Rather my point is: There are hundreds if not thousands of "experts" that paper-whip the "performance" of old milsurp rifles, and come up with completely "logical" and equally completely inconsistent with reality, sissy "standards". One of the great things about P.O. Ackley was that he never took all the "theorizing" at face value because he knew that for the most part, it was just so much hot air - He actually tested everything.
 
My opinion is that the SMLE, especially in its later incarnations, is built like a tank - it's brutish. That's one of the reasons I don't care for it esthetically. I'd love to see someone actually take one and try to blow it up much as Ackley did (unsuccessfully) with the Japanese Mauser. (Another ugly, brutish action in my opinion.)
 
22hornet,
 
I'll run the paper pressure numbers up to 56,565 PSI, which is the CIP standard for the 98 Mauser. I am confident the MK4 can handle that. You may relate that to the .220 Swift's max of 62,366 PSI if you so choose. Personally, while I have pushed a 98 Mauser to just a little over 60,000 PSI, my personal max for it is now around 53,000 PSI. Not because I'm afraid to go higher, but simply because higher pressures only beat the action up with no commensurate gain in bullet 'performance'. Based on my limited SMLE experience, and modest Mauser experience, I think the SMLE would be "comfortable" in the high 40's to low 50's. BUT... remember that I've never owned a SMLE. My 'tinkering' has all been when I could play, cautiously, with a friend's. So...
 
Pushed to 56,565 PSI, QL says the MV for the above mentioned bullet in a 24" barrel chambered for the Sprinter case, would be 4030 f/s using ADI 2208 powder. ADI 2219 would give you 4093 f/s. IMR 3031 would give you 4157 f/s.
 
Limiting the chamber pressure to 50,000 PSI, the ADI 2208 MV is 3878 f/s - for 2219 it's 3948 f/s - for 3031 it's 4015 f/s.
 
You MUST appreciate that QL's numbers are THEORETICAL and based on ESTIMATES of chamber size, bullet seating depths, and ESTIMATED case capacities. When these parameters are NOT estimated but MEASURED, QL makes accurate estimates of pressure and velocity. BUT, the QL values based on ESTIMATES can be quite different from REALITY once the actual numbers are known. DO NOT RELY ON THESE NUMBERS TO WORK UP LOADS unless you start down considerably and work up.

I'm looking forward to seeing reality when you get the finished rifle in hand and can work up some loads.

Paul