I've never tried the kits here in the states.
But I've handled at least 4 or 5 in South Africa, and had them on hand, of course that was long ago.
I could write an entire book on the never ending subject of just how filthy lousy and stinking they are.
I had a mind to tear one apart and make an artists metal sculpture from it.
Bear in mind, these were the real full-autos-not kits or put together.
Even with that they were not worth the cleaner used on them.
I had more jams, than you could have in your own cannery.
But, with that said, they are better to have than a pocket knife when in a fix, from what I've heard. I never had to use them seriously.
Firing accurately is not gonna happen.
You might have a closed bolt fire, with the semi though-I heard they use closed bolts for them.
Might be a little better.
All said though, they might be REAL fun in a modern semi.
Oh well.
D