Shore,
On the ak, what did you do to increase the gas block size, to accommodate the larger barrel in that area? I mean, I too have a an ak/450 and also a sks/450, but I also increased the gas block ID diameter, just curious.
Feed ramp.. Look at this pic (
http://www.google.com/imgres?q=feed+ram ... 33&bih=436), the six o'clock locking lug will need to be ground down to blend in with the other two 5.56 feed ramps, making one wide feed ramp for the 450, that is approximately 1/2" wide, for a .451 bullet.
I tried but failed to find a pic of our feed ramp, can someone try for me and include it here?
Porting.. I assume you have a set of numbered drills. Drill a small hole in the barrel, much smaller than you think is needed. The carbine length gas port of the 450b is about .091" +-, but you may want to start this exercise at say (assuming your ak gas port is at the same location as the ar), a #55 drill @.0520" (smaller if your gas block is closer to the chamber than the ar).
Using factory 450b ammunition, we'll discover the gas port size, by shooting and increasing the port size (one or two drill sizes at a time) until the bolt travels all the way rearward, "Reliably", (this will take some doing to determine on an ak, that does not have a bolt hold open device). When you've decided which drill size makes the action function reliably, then increase the drill size 4 sizes and that will be your combat function size. If you don't do this correctly and there is a very little room for error, the weapon will either be over gassed, which will damage the weapon or it won't function, as in short stroking, or it will become a jam-amatic.
Hope that helps..
..t