9x21s in the 356 TSW--

[XPman]

I have found some 9x21 Fiocchi 123 gr. FMJs @ 1280 fps, w/brass cases for +/-$20 per 50 rd. box...
OK, I am thinking strong about shooting them in my 356 TS&Ws, how will they do, will I need to alter the recoil/slide spring...???
Is this good ammo...??? Any Info/knowledge will be appreciated... I would like to get just a single box, but the S&H is stout that way, really not much more and the price drops a bit on a 10 box order... Any Info/knowledge as to what to expect from shooting these in the 356 TS&Ws...???
PS-I am thinking that the 9x19 is a good bit lower pressure round, am I right there...???
Thanks, and have a good one...XPman...

 

[bad_man_ one]

Yes,
It can be used, but whenever you use a shorter case, it will not headspace in the chamber as designed.
It will rely on the extractor to control the depth.
You could risk damaging the extractor.

The difference in the case lengths are about .020" plus or minus.
Depending on your chamber depth tolerance and the ammo length tolerances.
Where as in a proper fit would be .000" to .020" clearance from the primmer end of the case to the breech face.
With the 9mm x 21mm in a .356 TSW chamber, this clearance will be around .020" - .040".
The SAAMI Specs for the exterior case diameters, extractor groove and head diameters are all the same
w/in .001 to the .356 TSW, 9 m.m. Luger(Parabellum) and the 9m.m. X 23m.m. Winchester

NOT SO with the 9mm x 18mm Makarov,
it is the one that has some very different dimensions and also utilizing a .365" diameter bullet not .355"/.3555".

You will notice the 9mm x 21mm is not as hot as the .356 TSW, which has a max SAAMI pressure of 55,000 psi. (CorBon)
The max for a 9mm x 21mm is somewhere around 38,100 psi.
I do not have the exact SAAMI spec on that one.

Bottom line:
I would use it.................

Regards,
BM1