Is that a Reising, or are you just happy to see me?
Saw this in a news image from down in Old Mexico.
Captioned as “Masked and armed men guard a roadblock near the town of Ayutla, Mexico, on Jan. 18. Hundreds of men in the southern Mexican state of Guerrero have taken up arms to defend their villages against drug gangs.” With no attribution
The gun, for those of you who are hardware savvy, appears to me to be a M50 Reising submachine gun.
I did a piece on these little forgotten WWII gems for Guns.com last year that will give you more information but bottom line is H&R (yes, the shotgun fellas from Massachusetts) made about 123,500 of these .45ACP subguns to the design of one Eugene G. Reising from 1940-46 in several variants. The USMC used them in Guadalcanal before replacing them with more reliable gear, with the balance being issued stateside to state guards and the USCG for beach patrol (see below).
After the war many were handed out by the Office of Civil Defense (now FEMA) to police agencies for use if WWIII ever cracked open. This had led to a bunch of small departments still having these old guns around.
How this one showed up in Mexico is anyone’s guess. The forward grip and shortened/repaired stock is a nice, locally added touch.
If a gun could talk…
laststandonzombieisland 
One of my engineers remembers the little Ohio town he grew up in and that the police force had a Reising in its arsenal. It’s both fascinating and tragic that one these classics is in the hands of someone ‘not of this nation”. But just the same, if it’s deployed in the defense of free people I hope it airs out some bad guys.