Well, how about https://en.wikipedia.org/wiki/.260_Remington
No, you said a 6.5x55 chambers. You may have to work over a 308 case until you can get it to chamber and then fire form it out with a few grains of pistol powder and cream of wheat filler and have custom dies made.

Last edited by HalfaDouble; 11/04/19 04:04 PM.