- Never heard of either of them! - but I noted that this was another "Bottleneck" suped-up round (or is that 'souped-up?) that might be the new improved best-thing-since-sliced-bread.
Actually I should like this new cartridge as it is "a .30 Caliber" - or more accurately it is very close to being a high pressure, high velocity .32" - but it currently is not SAAMI specified and it is pricey.
7.5FK promises to deliver a 103gn .30 caliber pill down range at 2,000 feet per second for a muzzle energy of 960 ft.lb. as a long range hunting round.
BRNO 7.5FK Field Pistol. - 2,000ft./sec.
(looks a bit like an old Webley Air-gun)
Don't confuse this proprietary 7.5FK round with the FN 5.7x28 which is also a 'bottleneck" high speed hottie.
FN 5.7x28mm - Can Drive its .22"s at 2,800ft.per.sec.
Next addition is the .22TCM that looks like a 9mm necked down to .22" but it's actually based on 5.56x54 brass. This bottleneck also runs at 2,800 feet per second with 40 grain bullets and there is a conversion based on Glock 17 magazines.
.22TCM Compared to FN5.7x28, and .223" Rem.
Then there is the .357 SIG - developed in 1994 that can push-out its 9mm sized bullets from a .40" size necked-down case at around 1,500 ft. per sec.
- Then there is the .32 NAA from 2002..
.32NAA is a suped-up .32 ACP that appears as a necked-down 380acp case that can push its 60gn pills out at 1,222ft.per.sec.
- These bottlenecks all bring to mind that 'oldie-but-goodie' - the .30 Luger (7.65x21mm) - even this antique could manage 1,200ft.per.sec. way back when my old Co. Wicklow Dad was in shorts and bare feet.
- However - while recognising that it must be fun to pee-about looking to re-invent & improve the mouse-trap in hope of making a fortune - may I just slip-in an observation that even our nearly as ancient European 9x19 Luger can be driven as fast as 2,000 feet per second with a 50gn bullet? (Liberty Civil Defence Ammunition)
.. Time will tell as to how many of these will still be around in 2116 eh.. but we should remember that bottleneck rounds do feed very reliably in autos.