I have used both the STEN, THompson and M3 Grease gun maybe have put 10,000 rounds through them collectively, my ammo used to be free!
The Thompson is not a "spray and pray brute at all". It is very accuratte for any smg. On semi auto you can hit a man sized target a 100 yeard in the kill zone no problem. Given some practice you can do itat 250 yards if ther is no wind. With short burst the same thing hit wsie at 100 yards or less.
The Thomson is very heavy and so it is controlable even spitting out the .45 acp round. But there are two cylic rates and the military ones, as opposed to the very fast firing old Chicago gangsters 1920's version fire at reduced rate (750 rpm or 800) and very effecetive and controlable rate. The old military ones, I had M1A1 amde by Savage and they are not internally like the 1930 models, there is a fixed firing pin on the bolt face like the sten or M3. The roaring twenties version used complex 'Blish' locking system. There are fewer parts in a M1A1 than an old Chicago Typewriter too. The gun is very reliable really.
IN contrast the M3 Grease Gun is the slowest firing SMG ever made and about 450 rpm. It is very controlable. Also the M3 was fitted with 9mm convesion for NATO Europen troops but sledon was it evr installed. I fire one for grins, it takes 4 mintues to conver with NATO kit, fairs bit faster in 9mm but I will take the .45 acp version.The M3 is so lsow it almost does ot feel like you are firnf full auot to somee ctent if you are used to regular 650 rpm smgs.
AS for th STEN, I have a soft spot there as I used to have some as class 3 dealer. They are so cheaply made in tis mind boggling and they sold cheap back then too ( $650 each) Hence , I had to get one back then ( 22 years ago). The STEN is as cheap a gun as can be imagined. IT is all stamping except for the bolt and barrel period.
The big problem with the STEN is magazines which were made like the STEN by the tens of millions and some were made not to spec. The result is that you must test each STEN mag with the particular STEN gun you have for reliability.
I can just look ata STEN and peer inside the reciver and see how and exactly where the fixed ejector is welded to the inside of the reciver tube and tell which magazines will likely work in that gun.If you amtch magazines and do not loas but 27 rounds in the 32 round magazine the STEN can be reliable. The STEN design is Nazi design orginaly, guns look identical. The STEN was designed on the Erma SMG (Nazi STEN) that wer captured an atken back to England aftre the Dunkirk fiasco, The solider said "we neeedd one ot these kinds guns!" Up to that point the Britich were steadfastly aginst any smg and feling they had no purpose. So Sheprard and Turpin, the S and T in STEN designed the gun and built the first protype in 9 weeks!
The horizontal magazine is really a good idea in an smg. It has two advatages (1) You can lay flat and fire makeing yourself much less of a easy target profile, you can't do that with any straight down magazine smg as the mag forces you to the gun up and 'keep your head up' (2) The horizontal hold and the pistol grip are in two diffrent planes and at right angles to each other making a very steady grip. YOu can write your name on a large paer target with good STEN on full auto it can be so contraolabale.
In www2 some Britsh troops "lost" or destoyed" their STEN gunsa sthey thoght it was to cheap and unrelaible for them want to take into abttle, they previously had the Thompson. Having dirched their STEN they could get bolt action Enfiled which they fel safer with.
The STEN was redesigned and much beter made afetr ww2 as the STERLING SMG, arguably the best an most reliable smg ever fielded useing an open bolt design.
