Yup, sure did. Here’s what Fred Zeglin, inventor of the Hawk cartridge has to say:
http://www.z-hat.com/Rifleshooter.htm“Frankly, those smaller than .270 bore don't make good use of the extra case capacity.”
264 Hawk
http://www.z-hat.com/Hawk%20Ballistics.htm*85gr. Sierra 50gr. H4895 3540 fps
*100gr. Nosler 57gr. N160 3440 fps
*120gr. Nosler 60gr. IMR4831 3330 fps
*140gr. Hornady 54.5 gr. H4831 2810 fps
*140gr. Hornady 56gr. H4831SC 2925 fps
*140gr. Hornady 52gr. IMR4350 2990 fps
*140gr. Hornady 53gr. IMR 4350 3090 fps
http://www.z-hat.com/guns404.htm 57 grains IMR 4831 120 Nos SBT 3139 fps
58 grains IMR 4831 120 Nos SBT 3154 fps
55 grains IMR 4831 129 Hornady SP 2950 fps
52 grains IMR 4831 140 Sierra SBT 2749 fps
Nosler 6th, 6.5mm-06
100g, 3547fps
120g, 3294fps
125g, 3110fps
130g, 3151fps (Not a typo, its listed as faster than the 125g)
140g, 2906fps
The 6.5mm-06AI ought to be able to beat those velocities by a bit, say 100fps, making it – for all practical purposes - the equivalent of the Hawk version.
The advantage of the Hawk is the shoulder is moved further forward, like the Gibbs, providing more powder space. Remember I'm using an Interarms Mark X action, with a 3.5" magazine. That means a shorter neck will cause the very long, very high B.C. bullets I want to use (130g Scirocco, 140g Berger VLD) to seat deeper into the powder space, thereby reducing powder space. I figure the Hawk and Gibbs have some “cool” factor, but I’m not convinced I really gain anything with these cartridges. Besides, the longer neck, in theory, should help improve accuracy, if only a smidge.