OOW has excellent kits and coles distributing also has good ones.
I have a tutorial on my site www.projectguns.com
I also have bucking bars, spade grips and scope mounts.
Been building some AK's and need some advice on a 1919 in 308 or 30-06, What is best source for kits and build instructions side plates etc
Here is the forum devoted to the 1919:
You should find some info there. There is currently some ATF shenanigans regarding some of the "80%" sideplates and you will find the latest info there. Dunno who has the best kits right now, IIRC Sarco and Ohio Rapid Fire had some left too. Gunthings.com has some of the semi conversion parts and spare bbls in .308, as does ORF. Pirates spades are about the best bargain out there right now, especially his kits for the DIYer.
There is a member on the 1919a4 web site named 30calmachinegunner that does the semi mods to the internals for a very resonable price & his work is excellent also a member named ironcreations that sells top notch reproduction Tripods also Badgerbob has econo Pods real cheap that work great I have one & really like it