During the 1980s, the US ran the Joint Service Small Arms Program to reduce the number of different small arms in US inventory. The most significant outcome of this program was the M9 pistol, but the program also considered adopting a submachine gun. The requirements were bit tricky, with things like a low rate of fire but also a very high-ROF burst option, and caliber conversion options. Saco Defense got its hands on a Brazilian Uru submachine gun and used it as a model for their Model 683 for this program. Only a few were made, and we are taking a look at them today…
Thanks to the Institute of Military Technology for allowing me to have access to these prototypes and bring them to you! Check them out at:
Full Uru video:
H&K SMG I/II video:
“(…)a low rate of fire but also a very high-ROF burst option(…)”
This requirement seems as outright challenge against history of full-automatic weapons of 20th century, as these either
– spawned version which lacked select-rate-of-fire gizmo, e.g. Gun, Machine, 7.92mm, BESA https://www.militaryfactory.com/smallarms/detail.php?smallarms_id=221 tank machine gun had ability to selected between 500 and 800 rpm in Mk II and only 750 rpm in Mk III
– managed to fall into oblivion, e.g. https://guns.fandom.com/wiki/McCrudden_light_machine_rifle
The original Chauchat and M1918 BAR had semi and auto fire available, but were primarily intended to be fired semiauto. The later M1918A2 had a low and high cyclic rate. The lower cyclic was intended for general ground use and the high cyclic was intended for antiaircraft use. I suspect not many airplanes were hit by aa fire from a BAR, but the technique was covered in the manuals and taught to automatic riflemen.
Let me see if I get this straight… SACO copied a weapon without clearing it with the original designer, and then showed it to them? Is that what they did?
WTF?
I had limited respect for SACO-Maremont before this, but… Wow.
After entertaining sight-handle thing (which was introduced by SACO and is not present at Uru) they seems like having… limited knowledge about real world application.
Considering that ends of said tube are open they look as ingress for dirt and due to its’ shape it would need tool of shape of negative of that tube.
I presume that they might do it that way to have unblocked line-of-sight after installing barrel with suppressor, but if they did, then they ignored important thing. Whilst using suppressor at 9×19 weapon you should be using subsonic 9×19 cartridges, which in effect have different trajectory and that means adjusting sight. For that purpose adjusting method which would NOT require firing shots to confirm zero would be advantage, especially considering limited life of suppressors.
I am also wondering if that sight-handle has enough range of movement to envelop both 9×19 and .45 Auto trajectory. If not you would need different version for each cartridge and during barrel swap you would also need to swap sight-handle and adjust it.
is: “(…)tool of shape of negative of that tube.(…)”
should be: “(…)tool of shape of negative of that tube to clean it.(…)”
In the 80s, none the less, when red dot sights were a thing, and the MP5 was already 20 years old… they decided to bootleg an essentially 1950s-style SMG and add sights that I would expect on a Nerf gun.
Maybe they wanted to get a deal on licensing with Olympio if they got the job producing it in more than 3 pieces.
I wonder in that 2nd version not using plagiarized Uru sear/trigger, could somehow happen that you release the trigger and (front, main) sear does not catch the bolt but rather send it chambering new round.
Also, why is magwell canted as in UZI and its magazine it is straight.
Probably copied from the early MP5 aka HK54, which had the same arrangement.
As I understand it, HK adopted the curved magazine for the MP5 in 9 x 19mm from the Madsen M1953.
https://modernfirearms.net/userfiles/images/smg/smg60/madsen_1953.jpg
clear ether
eon
“Probably copied from(…)HK54(…)”
Why are you suspecting that Saco Defense copied this feature from that weapon, rather than just from URU, which also do have canted magazine, see 1st photo from top at https://modernfirearms.net/en/submachine-guns/brazil-submachine-guns/mekanika-uru-eng/ ?
Though Uru had single feed magazine. Now, as I asked, was it a special function with uzi mag, or purely cosmetic thing to get it looking like original Uru…
If only the M3A1 had been remembered by anyone other than the folks in armor at the time.
Cheap tho relying on GM remembering where the stamping dies were, readily suppressed and at one point avail in 9mm and .45. The oddball hi/lo fire rate requirement could have been addressed in a solidly “meh” fashion w light or heavy bolts or a removable weight. (pick a medium ROF and go away)