I've read about the "desirable" zig zag laser cut brakes, half moon cut brakes, two piece construction, etc..... I've looked at a number of web sites that show picutures and I just can't see the differences in the brakes, aside from some outward cosmetics.  What exactly are the zig zag cuts, etc.  I'm looking at my Bulagarian brake right now and can't figure it out. I'm just interested in the real brakes, not the after market repros. Thanks!

As you noted, there are many variations of the 74 brake.  As far as US reproductions, the least desirable is the '74-style' brakes from CDNN, Tapco, etc.  Basically, if it's under $20, it's POS one-piece without properly spaced gas ports (usuallly they're placed at TDC (top dead ceter), which is incorrect).

The best brakes are the ones offered by AKUSA and Krebs.  I haven't seen a Krebs brake up close, but I have an AKUSA brake, and it's wonderful, and about 1/2 the price of the Krebs unit.  It's a 2-piece design just like Krebs.  You can see a bit of the two piece design in this pic.  You'll see the insert, which is pressed into the center of the brake.  I'm not aware of anyone who does the Soviet zig-zag cuts, and I don't believe the Russians even do that anymore.

take care,
Tec

I have a brake from the Bulgy 74 kits to compare to my brake from akusa/ak-103.com. Other than the Bulgy's chrome lining and the 5.45 hole, there is virtually no visible difference between the Bulgy and the 7.62 bit from akusa.
The expansion chamber/turbulence, irregularly spaced upward ports, and insert with crescent moon slots directing gasses to the front paddles work very well on my SAR1 plate blaster.