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Italian GWOT Steel: the Beretta AR-70/90
🕑 Added 2023-07-07 12:00:02 +0000 UTCWhile the Italian military did adopt the AR-70, it did not actually issue them to all troops. Most continued to use the 7.62mm BM-59 until 1990 when the Beretta AR-70/90 was adopted. This rifle was a substantial rework and improvement of the AR-70, using AR-pattern magazines and a 1:7" twist barrel to run the SS109 62gr ammunition chosen as the new NATO standard in 1981. The 70/90 also added a 2-position gas regulator to the design, while carrying over the folding bipod and grenade launching capabilities of its predecessor.
The AR-70/90 was made in semiautomatic from by Beretta for the civilian market, but only after US regulation prohibited its importation. As a result, these rifles were essentially nonexistent in the US until a few years ago, when a number of cut-up parts kits were imported. Several small shops set up to make them into semiautomatic rifles with new US-made receivers, including Brimstone Arms, who made this one for me.
Comments
But of course! You probably know I was the first person to have a firing AR-70/90 from this recent import of parts kits. One of the big mysteries was the how and why of those huge blob-headed welds. The "how" is fairly simple...they just used a MIG with a cup at the end of the "stinger". The "why" is a bit more interesting: The underlying parts of the receiver like the trunnion and rear lug plate are heat-treated alloy steel. Well, at least the trunnion is...can't swear to the lug plate. The sheet metal is just low carbon steel, and far weaker. The idea of the blob-headed weld was to increase the amount of sheet metal area in each joint. Why? Because stress is force divided by area, and the larger the area the lower the stress.
*Gun Designer. Jesus...uh Gun Jesus! And thanks. ;-)
Forgotten Weapons
Haha - I'm no gunsmith, and he's a heck of a gunsmith. :)
Mark Farris
Wow never though Mark Serbu could school Gun Jesus.
Forgotten Weapons
Damn. Thanks for that!
Loke von Post
Ahhh! I was just wondering why it came off so easily xD Thanks for clearing that up for me :)
Guido Schriewer
seems like a good system but man those italian rifles are always sort of oddballs.
FYI, the rear lug plate and trunnion aren't riveted in, they're welded. Beretta just used these giant, blob-headed welds that look like rivets.
Forgotten Weapons
Crud, that's embarrassing. It was indeed an editing mistake.
Forgotten Weapons
You are both technically correct...the best kind of correct. :)
Matisse Enzer
And to be pedantic it is bullet LENGTH for a given caliber not weight that has the major influence on the twist rate required for stabilization. Generally speaking of course heavier bullets are longer but technically it is the length that matters. So geeky ...
Matisse Enzer
I wonder if the hood of the gas cutoff is part of a sighting system for rifle grenades?
Tony Pardoe
You missed the removal of the flash hider/grenade launcher part of the process from film. It looks like you can just randomly yank the gas’s block off. Probably an editing issue.
Bruce Brodnax
*Technically* the 1:7 twist barrel is required to stabilize the projectile from the tracer ammo matching the SS109, not for the SS109 itself [which is quite happy w/ 1:9], but you knew that... 😉
