Gunsmithing as I mentioned earlier is a practical hobby and skill (kinda) I enjoy. You definitely have to have a feel for it. Though I'm not a master at it I'm fairly in tune to the workings of a firearm and what makes them work and tick. I've worked on a goodly amount of firearms in my short time on this earth but there is one gun that no matter WHO is using it....It will never FAIL TO JUST SIMPLY WORK. The AK-47 Family of firearms has been a popular gun for the home builder lately. For about the same price as buying one off the shelf (so to speak) you can build a legal semi auto AK-47 (so long as you have the pre required tools to do so....we did....and then some) In the case of the RPK I have $254 in it exactly
Usually to build one of these AK's or its clone one needs an assortment of punches and hammers. Cold chisels, a good anvil, leg vice or LARGE table top vice, welder (optional), large case of Mt. Dew, hydraulic press, $0.23(0_o) in pennies or so to use with the press to protect the barrel and perhaps an adapter for a air hammer to rivet rivets in.
The above picture shows my very good friend using a tig welder to weld up the front sight on the RPK after I atempted to remove it to install the new bipod (one was not installed when I got the kit). I gave up and simply busted the rivet out of the bipod to install it.
This being the 3rd AK clone that we've built we tried something a little different when it came to the receiver. In the first place it was the wrong receiver it was in fact one that was intended for a folding stock AK however it was on sale and I needed a receiver for the project (cost was $40). To fill/patch the large holes we cut and ground patches out of the old receiver which was actually a little thinner than the new receiver...not sure why. But after the receiver was patched up I had Anthony just weld the rear trunnion in as I did not want to mess with locating and drilling holes for the rivets that had to be put in!
The RPK's actually had the front and rear trunnion spot welded to the reciever so I had my friend spot weld the front after I drilled holes in the receiver. It serves to stiffen up the receiver being the RPK was built as a LMG( in theory). Now you gotta remember this was a Russian design made for the dumbest peasant to use. These things JUST FREAKING WORK. I've yet to have a jam in any of my builds, however we did run into a problem with upper rail length in my friends Romy G but that was fixed with a buffer welded in front of the rear trunnion so the bolt would not pop itself out of the reciever.
These builds are fun and if you have the few tools that are needed it can be a relativly painless build. The first one I did (the Yugo underfolder) proved to be a hard first build as the folding stock assembly had a lot of jesus parts (JESUS....small part springs across the room)