Exotic (super-fast) ammo for CZ-52

Interesting....

It's been a while since I've lurked over here..

The round you describe is also known as the .224 TIMMS, and I have been experimenting with it.

In the graphic (attempting to post) is one of my setups illustrating an early prototype load.

A 55 gr. .224 bullet is the heaviest yo can use in a CZ-52 and have it fit into the magazine.

My last load (appreciably hotter than the proto shown) was feeding from the magazine and cycling the action reliably.

After about 2200FPS the sabots seperate from the bullet at or near the muzzle and pass through the screens together, making an accurate reading impossible.

I estimate the velocity of these rounds to be in excess of 2400FPS, but will have to superglue some sabots on to the bullets an run those over the chrono again to be sure.

Accuracy has been disapointing, and I partially attribute this to the rate of twist in the rifling probably being too fast for these lighter bullets and "overstabilizing". I also considered such a neck-down modification, and assume that the rifling rate-of-twist has been adjusted appropriately in those barrels you are making.

It seems to me that the Russians were fooling with a similar 5.56MM "Wildcat" some time in the '70s(?)

Just watch your chamber pressures; the floor of the CZ-52s chamber is pretty thin and the cam block retaining pin goes right through it. Pressures on the sabot loads are kept down somewhat by the very low friction between the sabot and the bore. With copper to steel running down the tube in a reduced - caliber barrel, your friction coefficient will be much higher, as will chamber pressures in all probablility.

If I were to wildcat the 7.62X25MM, I think I would take it down to 7MM. Unfortunately I do not have the wherewithall to whittle out the prerequisite barrel and loading dies.

well I think you are going in the right direction
FN has dumped a big chunk of change in to developing their new round and the guns for it,
as I understand it, the new FN round is for LEO use only.
One of the attributes that is "talked around" about this cartrige is the penatration capabilitys through kevelar vests...................
the idea is that the bad guys would or could wear body armor and there for the leo's need a Pistol round that would defeat a class III vest.
Mmmmmmmmmmmmm
It sounds like just more marketing.

The technical attributes of new firearms are seldom anything "new"
so to sell something "found anew" the gun companys spend big bucks
ya ever notice that what we are talking about has simularitys to the 25- 20
from about a hundred years ago...................