The 6.5 Wby was a wildcat using the 300 Wby case, until Wby recently made an honest woman of her. What did they use for the parent case? I can't find anything on the internet.

They went with the 300, necked down to 264, like most of the old wildcats.

I Goggled "6.5 Weatherby" and got 379,000 hits...at least for the Weatherby name...several very good articles, one from the Weatherby site, and comparisons on the 6.5 Weatherby, 6.5-300 Weatherby, "new" 6.5-300 Weatherby, 6.5x300 Weatherby, etc, to several other 6.5 "Magnums".

You might find them interesting.

With all the screaming going that went on over the 264 WM and now the 26 Nosler, it's going to be interesting on what an even LARGER case generates in the way of howls.

Way back when I was doing Oehler 33 chrono test at the local shooting range, I did a 264 WM with a 24" bbl for one individual, 5 - Horn 140 SP's that came in at ~2700 and change, can't remember the exact numbers now but he didn't take well to what showed up and wasn't having any of it...wanted to chew on me a bit...I couldn't settle him down at all even by offering to develop some loads for him.

I had a friend that had one of the earlier 26" Win 70 and I had chrono'ed several loads for him with several 120-140 gr bullets but we were never able to match factory velos even with the two diameter bullets but they were very close...those "real" numbers can be achieved now and surpassed with todays powders.

I think now the Weatherby with an additional 2" of barrel, 28", would do quite nicely...argumentatively speaking...

And one inch of free bore, which is why I don't do Weatherbys.

I did a search seeking an answer to the question about the new 6.5 Wby parent case, with no success. Even on some of the forums where one might expect to find it. So, thanks for the info.

This type of cartridge doesn't really appeal to me. Law of diminishing returns, muzzle blast, etc. However, I am glad it's a free country and folks can pursue their interests. Without the inventors and experimenters we'd still be shooting black powder or throwing spears.

Parent case is the full-length .300 Wby.