I have a complete, and 90% original Argentine Sistema that I bought
about 10 years ago. It has been an excellent pistol from them until now.




About 5 or 6 years ago I had a kaboom in this pistol due to an
overcharged round. I had just gotten my Dillon 550B and I double charged
a round* and didn't catch it.  Well, I found it and as you can imagine,
my day got interesting. *(I determined this by doing it again, but
catching it this time.)



The result of the KB was a destroyed mag, wrecked grip socks, and a
bulged barrel. The slide locked up, but a few wraps with a 2X4 and it
came open. The barrel was toast, but the frame and slide appeared to be
fine. I happened to have a USGI replacement barrel in the range bag, so I
dropped it in, performed a safety check ( that did NOT include a head
space check), and proceeded to finish my range session. The pistol never
even hiccuped for the rest of the day. A close inspection of the brass
did not reveal any signs of problems.
About a year ago I took this pistol apart to refinish it and noticed
that the slide had an ever so slight bulge in the sides. I used a
precision ground 1 2 3 block to check it and sure enough, it was bulged.
I put the slide in a press and pressed the bulge out. I refinished the
pistol and put it back together.



I thought about the bulge and the effect of pressing the bulge back. If
the slide bulged, then that means that the metal stretched. And when I
pressed the bulge back, that stretch had to go somewhere. Just like re
sized brass gets longer for the same reason, this slide had to have
gotten longer. And since the bulge was between the locking lugs and
breech face, that means that the distance between these two critical
surfaces had to increase. Since the breech face was now further away
than it was, that means that the head space was longer than it was. So, I
bought a set of 45ACP head space gauges and sure enough, the head space
was well beyond NO GO. With the NOGO in the chamber, I could wiggle the
barrel back and forth with it fully in battery.



So, I have been shooting this pistol for several years with
significantly excessive head space. Clearly this slide was unserviceable
so I cut it into pieces to prevent it from ever being used again.
But, I named this thread "A Pleasant Find." So, why don't I get to it
you say? Well, here it is. While looking for something else, I found a
Remington Rand 1911 slide lying in a drawer of gun parts. I vaguely
remember this being in a box of stuff that I acquired in a trade a
gajillion years ago. Anyway, I put the barrel from the Sistema in the
slide and it fit and head spaced. I put it on the Sistema frame and it
fit. A safety check was performed and passed. A couple of tweaks of the
extractor and it was flinging dummy rounds like a champ.



GOD willing, I will take my new hybrid out to the farm today and see if it will shoot.