I have a 270-08. I am also new to wildcats. I would like to work up some loads using either 140gr or 150gr bullets and achieve a muzzle velocity in the 2700fps to 2800fps. Should I use data from the 260 Remington, and 7mm-08 for the same bullet weight, or sectional density?? Thanks for any help in advance.

With regards,
Chris

While I have never had a .270-08, I thought seriously about having one built years ago. I had read an article about the ".270 Redding" and it sounded like the perfect combo cartridge for deer and rock chucks, pushing the 130 gr bullet 2800 fps and the 90 gr hollow point around 3100 or so. I checked Ackley's Handbook for Shooters & Reloaders Vol. 1 and it lists some loads for the .270/.308, but they seem a mite high. He shows 45 gr of 4350 with the 150 gr bullet for 2782 fps. My current Lyman loading manual shows the same charge for the 154 Hornady in the 7mm-08. I don't believe Ackley had access to sophisticated pressure measuring equipment back in 1962, so I think it very wise to start well below his maximums and work up slowly and carefully. (Good advice with any cartridge, much less a wildcat) Given your circumstance, I would probably start at or just below published maximums for the .260 Remington with as similar a bullet weight as possible. Then work up in 1 gr increments until you achieve your desired velocity, or you encounter signs of excess pressure. If you aren't sure what those are, you maybe should have considered loading a lot more standard cartridges before venturing off to a wildcat. I would think that 2700 fps should be reachable, certainly with the 140 gr bullet. (I like the Nosler Accubond). I still think the 130 gr bullet at 2800 or maybe even 2900 if you have a 24" barrel would be the optimal choice for deer and antelope.
The reason I never pursued the .270 Redding (or .270/308) is because I now own a .270 WSM which is easily loaded down to 2800 fps with the 130 gr bullet, yet also has the ability to push the 140 gr Accubond over 3100 fps if I need to. I like the short action and 24" barrel and it is still reasonably light weight and handles nicely in the Model 70 Super Shadow. Good luck with your new wildcat. Let us know how it shoots!

I used the 7mm-08 data to work up loads for my 270-08 with 150gr projectiles ( Speer, Barnes, Nosler partitions. )
I got some 150gr Bergers I want to try.
It was difficult to find other 270-08 shooters when I started out.
I use ADI powders. We do not get IMR Powders anymore.