I have recently received a 270 /300 custom wildcat by way of a death in the family.The RCBS reloading dies and reloading info came with it. I reload all of my others 7mm ultra mag,300 win mag and 270 etc.But I haven't got a clue on where to start with this gun.Do I what?Any info would be greatly appreciated I haven't the slightest idea.The gunsmith that built the gun and made his shells is no longer with us either.

Thanks in advance Sp

Welcome to the Campfire Sp.

Which case is the round based on?

The .300 Win Mag? The .300 H&H Mag? The .300 RUM? The .300 Savage?

With this info we can get you started.

The die box say 270/300 Win Mag

Welcome to 24hrcf from here as well!! Hope we can be of some help. Yep, need this info to help but in the case of 300Win based wildcat you could start with 270WBY Magnum data and likely be able to go up from there a bit. Would be really similar but with a shorter neck and longer case body a touch more powder would be useable and even needed.

I shoot a wildcat that has a similar dilemna in that is is like a 340WBY with again a shorter neck and longer body. As soon as I reached velocities that were 100fps over 340WBY numbers I quit adding more powder. Maybe could have done more, but no need to and wanting to make sure my pressures were not excessive. I don't trust the old measuring sticks of how a promer looks etc anymore. When I hit a safe and sane velocity number with a slow burning powder like 7828SSC or similar I quit right there BEFORE I get a flattened primer or sticky bolt lift. Would suggest you do similar with yours if it is a 300Win based case.

Should be one heck of a flat shootin fun round and rifle! good luck and good hunting. MARK

OK, so we know that it is, as suspected, a 300 Win Mag necked down to 270. Above comments work and apply. Start with 270WBY data and go forth from there. what you have will be very very similar. RE velocity numbers.... WBY chambers have lots of freebore in them to allow larger powder charges than would normally be prudent so I would quit, if I were you, when I hit top speeds for the 270WBY round and not push the pressure and speed envelope past that point. This is pretty darned fast, as you might already know. Would also stay with the slowest burning powders compatible with the round. Good idea as well to keep to well constructed bullets such as the Barnes TTSX's. Such a bullet in 120 or 140gr flavor would give you all you need and want from this round.

Safariman said it.
Start with .270 Weatherby Magnum data and work up slowly with an eye towards pressure signs.

Safariman has advocated a sound and safe reloading philosophy. Stop when you reach .270WBY velocities and you'll have a flat shooting, deadly cartridge.

The gunsmith has the powder as 75 grains of Reloader 22 which I already have at the bench and with a 130 grain Nosler Ballistic tip at a velocity of 3485 fps With the IMR 4320 60 grains 130 Nosler ballastic tip 3252 fps.My question mainly is do I use the 300 win mag case and the sizing die will neck it down for me?No trimming.He has left out the O.L. so i guess i will have to fit it.Those velocities are dead on the 270WBY.Thanks for the help provided.I have the gunsmith data and the Barnes,Speer etc book data just need to make sure of the case.

i would sneak the die down on some 300 till it gently closes on the brass. load some 270's long and look for rifling marks. back it down till they go away then add a few thou.... start with 72 grains of 22 and see what the brass looks like and head up from there.. the 257 roy and 72 grains of 22 works for the 100. math says 72 of 22 and a 130 in the 300 should be a great starting point. fireform..

load with it touching the lands and work up from 72 grains.... watch for pressure. when your groups open back off on your oal and find the happy medium.... JMO

woofer