Hangingrock
Member
The South Vietnam Army had their fair share of them along with Popular Forces that I saw.
Where did all the Thompsons go?
- Thread starter spartanpride
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Sam1911
Moderator Emeritus
This of course is a reproduction, semi-auto, probably by Khar.
http://www.auto-ordnance.com/PA-1.html
An original, military surplus, transferable full-auto would cost a bit more.
Heavenlyfire
Member
Probably, I have no clue, didn't get to see it or the owner.
As I am interested in how things tick, and the M1928 has that unusual Blish effect locking mechanism, I was eager to see one. And how it worked.
I was lucky to be able to disassemble a bolt, receiver, and take pictures.
Clever mechanism.
I was lucky to be able to disassemble a bolt, receiver, and take pictures.
Clever mechanism.
Sam1911
Moderator Emeritus
That looks like dykem all over that gun. You mill the receiver yourself?
SharpsDressedMan
member
Yeah, is that receiver registered?
Looks recently machined. Also, the gun will function fine without the blish lock. Designers later determined it wasn't needed.
Looks recently machined. Also, the gun will function fine without the blish lock. Designers later determined it wasn't needed.Sam1911
Moderator Emeritus
I was assuming it's a semi, which would be perfectly fine to manufacture yourself. I don't know enough about the approved semi versions to tell the difference from those pics, though.
Actually I was tempted to ask if he'd proven once and for all if it really did what Blish said it would do! I once was told (or read...can't remember) that the theory was hard to prove in practice. The guns worked, but whether or not the Blish system actually DID anything was always in question. I'd love to hear more about that.
SharpsDressedMan
member
Sure looks like a full auto to me. Semi bolts are thinner, I believe, and it would still be a an NFA because of the short barrel.............
Tommygunn
Member
I don't think that's a semi receiver guys, as they would not put the slots for the Blish "ears" in the semi, which operates "striker" like a Glock.
Also, while the Blish device did not work as originally believed, it DID work. It was originally believed that it used a "coefficient" of friction to slow the rate of fire down. That is, on the original pulse of firing, the friction overcame the recoil until the recoil dropped beyond a level and then the recoil force overcame the resistance and the bolt cycled.
An interesting article in a collector's magazine (dangit I have forgotten the title....) showed what really happened. The authors acquired an additional Blish lock and milled off the two outside ears --- the ones that fit in the slots you see in the receiver in that Beautiful beautiful photo above (THANK you Slamfire1!!!!!!!!!!!) and operated the gun with the device just holding the Actuator to the bolt (which is required for the gun to work). It was discovered that the rate of fire actually increased about 100 RPM. This way. But, what was causing the thing to actually work if not friction????? The difference in the angle the Blish device rides up in the bolt assembly is different than the angle it rides up in inside the receiver, and this forms a type of lever effect, and THAT is why it actually does work.
Now, the M1 and M1A1 version deleted the Blish and altered the bolt weight and the recoil spring, and achieved a similar rate of fire. So, despite the fact the Blish device really did work, albeit in a way the designers wouldn't know, the fact remains it was not the best way to slow the rate of fire down. The later military M1 versions did just fine with their design and neither had the Blish, although the M1 did have the hammer and firing pin.
JUst a FYI.
Also, while the Blish device did not work as originally believed, it DID work. It was originally believed that it used a "coefficient" of friction to slow the rate of fire down. That is, on the original pulse of firing, the friction overcame the recoil until the recoil dropped beyond a level and then the recoil force overcame the resistance and the bolt cycled.
An interesting article in a collector's magazine (dangit I have forgotten the title....) showed what really happened. The authors acquired an additional Blish lock and milled off the two outside ears --- the ones that fit in the slots you see in the receiver in that Beautiful beautiful photo above (THANK you Slamfire1!!!!!!!!!!!) and operated the gun with the device just holding the Actuator to the bolt (which is required for the gun to work). It was discovered that the rate of fire actually increased about 100 RPM. This way. But, what was causing the thing to actually work if not friction????? The difference in the angle the Blish device rides up in the bolt assembly is different than the angle it rides up in inside the receiver, and this forms a type of lever effect, and THAT is why it actually does work.
Now, the M1 and M1A1 version deleted the Blish and altered the bolt weight and the recoil spring, and achieved a similar rate of fire. So, despite the fact the Blish device really did work, albeit in a way the designers wouldn't know, the fact remains it was not the best way to slow the rate of fire down. The later military M1 versions did just fine with their design and neither had the Blish, although the M1 did have the hammer and firing pin.
JUst a FYI.
Sam1911
Moderator Emeritus
Thanks TG! That is exactly the explanation I wanted! The idea originally behind the Blish system (didn't it also require dissimilar metals? Hence the brass or bronze locking block?) was so carefully thought out and "science-y" that it sounded really cool, but the more you think about it the more you've got to give it the 
look.
As to the receiver, it could be a dealer sample as well. We have to assume good things until we're told otherwise. Slamfire1 hasn't said.
look. As to the receiver, it could be a dealer sample as well. We have to assume good things until we're told otherwise. Slamfire1 hasn't said.
az_imuth
Member
Here are a few of them...
...and a few more. I can't remember where I found these pics, but it seems like they were were taken somewhere in SE Asia. Whereever it was, what an absolute waste.:banghead:
...and a few more. I can't remember where I found these pics, but it seems like they were were taken somewhere in SE Asia. Whereever it was, what an absolute waste.:banghead:
Jeremy2171
Member
I had a '28 for a while. When we got it was in parts but I got it back together and it ran well on WCC97 Match grade ammo 
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