Home Forums Hunting & Shooting Custom Rifles & Wildcats Prototype 1.0

Something I've been foolin' with.
.338 calibre in a 585 Nyati case.
83.5gr IMR7828 SSC = 2836fps

That sucker looks awesome.

What size is the rim? That Nyati case rim has been cut down.

Tony

It is turned down to .590, but has also been at .532. The .590 worked better.

Same speeds as RUMs and WBYs but with up to 15% less powder. Next set of rounds will probably be with 225gr SSTs. Might hit the 3200fps with 87grs.

Looks like a fun project..dave

Visually it reminds me of the 243 WSSM. Neat. Would something like H1000 or IMR 8133 be too slow?

And therein lies a problem. The powder supply chain is spotty, so I have to use what is on my shelf. Also limited to using QuickLoad to estimate pressures, good in the regard that it tends to estimate low, but that translates into more loads fired at the low end. Prime example being the 7828 load, where QL estimates pressure to be just below max at 79.4grs, but brass and bolt indicate 83.5grs. More rounds to find max, but more shooting means more fun, so win-win.

What is the length of the case?

Case is formed at 2.081, trim is 2.070.

FINALLY !

A REAL wildcat on the Campfire !!!
Most still think a 338-06 and 280AI are the cats azz on here.. redundant 60's stuff that has been done 100 million times X100

I started a similar one in 375 cal a few years ago but settled on the 500 Jeffery case due to there being no suitable "short" actions for the Nyati case diameter

My 375 Mercenary is off the full length Nyati case with a CheyTac rim diameter

Keep us updated on your progress, this is a really cool WILDCAT cartridge

That doesn't come free.

Always willing to listen and learn. At what expense are you referring to?

The forming dies used have been sized to have the ability to stop at any given bullet diameter (above .338), so a .375 or 9.3mm, etc. is possible. I wanted to continue down to 7mm, but I thought that might be pushing the envelope too far.

Pressure, if only obviously.

Yep.

How is it throated ?
For pressure consideration.
Short and tight ?
Weatherby&Creedmoor Style freebore?
Antique, coned-up-breech, leade-only throat ?

Thanks to Tony for buying my .585 Nyati basic brass from Bertram.
I came to my senses.
I have been expecting a .585 SOCOM to be announced one of these days.

"Pressure, if only obviously."
Not sure which way you're going with this. If you mean the point at which pressure signs appear, why would I go further? If you mean downloaded to reduce pressure, why would I go slow? Perhaps I am not grasping your context. Help me out with this.

"Short and tight ?
Weatherby&Creedmoor Style freebore?"
Not sure what a Creedmoor throat spec is, but the WBYs and RUMs use lots for gas expansion, so I guess this one does too. Not coned.

If you're getting a certain level of velocity with less powder then the pressure is higher. There's no free lunch.

You have a reamer drawing ?
If not, you need to know how much free travel there is
for a right-cylinder slug of caliber diameter
moving from case mouth to first contact with rifling.
QuickLOAD is notoriously absent of any allowance for throat.
From your reading of the tea leaves it sounds like you must have adequate length of throat.

Mathman has it exactly.

Velocity is dependent upon area under the pressure curve. Using equivalent powder burn rates, it is impossible to produce greater velocity with less powder except in a smaller combustion chamber with increased pressure.

How do you gain increased net energy with less fuel? Only by burning it faster and creating more pressure.

The "more efficient cartridge design" is myth. The facts that matter are combustion chamber volume, and mediating factors such as very slick bullets and lots of free bore. (This is why every bullet I buy gets impact plated with moly. Moly reduces chamber pressure, changes the rate of rise in the pressure curve, and lowers velocity with equal powder charge.)

What SAAMI calls safe pressure, and what I call safe pressure, and what you call safe pressure are likely not the same things. But make no mistake, if you are exceeding 300 Win Mag 180 gr bullet velocities in your 30-06 with 180 gr bullets. Well then the 30-06 is running much higher pressure than the 300 Win mag.

What you are doing is equivalent.