To make templates for the trunnion and rear block, just use a post-it note. Line up 2 edges of the post-it with 2 edges of the part. Then rub over the holes with the side of a pencil. Cut out the holes and compare your templates to your parts. Make any adjustments necessary. As a bonus, the post-its are self-adhesive.
On the trunnion, I slide the top edge of the paper against the groove for the top rail, and one edge lines up with the front of the trunnion.
For the rear blocks or stock tangs, I use the groove for the top rail and whatever other reference point is convenient.
When I first started drilling the holes, I usually started with a smaller bit. Then I opened the hole with a file to make any adjustments. Now, I can usually get it right the first time.
You can also try scanning your parts on a flatbed scanner. Print the image in 1:1 scale and check the hole locations against your parts before drilling.
If you're looking for a basic AK receiver template, AceArms has a really decent one available for free download on their site:
www.acearms.comHere are a few links to buttonhead cap screw suppliers. You should be able to find these at local hardware stores like Ace, Lowes, Home Depot, Sears, etc. If they do not have them in stock, they should be able to order them for you. A box of 50 to 100 should be $4 to $7 accordingly.
www.thread-rite.com/unbrako/button.htmwww.fastener-express.com/subcat.asp?0=207mjvail.com/holokrome/bhcs.htmlwww.midwestsocket.com/socket-head-cap-screws.htmwww.microfasteners.com/catalog/products/SSC.cfmwww.earnestmachine.com/cap_screws.htmwww.circlebolt.com/socket.htmwww.nutty.com/bsc.html