One factor you have to consider is the type of stock you'll use.
These SA and SLR Bulgarian rifles have only a top tang on the receiver.
Some receivers were slotted for a lower tang, some were not cut.
Your choices are:
Install a lower tang.
If the receiver is cut for a tang this is a matter of riveting in a lower tang.
If the receiver is not cut, you'll have to cut the slot through the "bulk head" between the stock socket and the inside of the receiver, then rivet in the tang.
Another option here is to use button-head socket screws and nuts instead of rivets. This eliminates having to get a riveting tool that will work in that area. The screws are plenty strong enough and using Loctite on the nuts gives a permanent job.
All you have to do is make some small clearance cuts on the wood socket area to clear the nuts.
In either case, you have to remove one trigger guard rivet and drill another hole in the receiver for the rear rivet or screw.
Second option is to buy a special SA-SLR butt stock kit from Ironwood Designs. This mounts with a through-bolt through a hole in the stock and screws into a special square nut that fits inside the receiver.
This eliminates having to alter the receiver or install a lower tang, and the Ironwood stock is very strong.
All you have to do is install the stock and tighten the bolt.
The only down side is that you can't put a cleaning kit in the stock.
http://www.ironwooddesigns.com/IWDNEW3B12_2.html
What NOT to do.... DON'T just put a stock on the rifle without a tang or by using the Ironwood stock.
First, a standard milled type stock will have a cut for a tang on the lower side and without a tang you'll have an open slot in the wood that looks bad.
Most important, the socket in the receiver isn't very deep and and the stock is just wood.
If you use only a top tang and put any stress on the stock it can pull out of the receiver, and this breaks off the upper tang.
Then you're really screwed because the receiver is hardened, especially in that area and you can't just weld the tang back on.
A buddy of mine was at a shoot a few years ago and a shooter was using an SLR-95 rifle. When they went into the prone position, he dropped down and used the stock to lower himself into the prone position, as trained by the military.
He put a little stress on the butt stock and it pulled out, snapping the top tang off the receive.
The same thing can happen if you accidentally give the bottom of the stock a bump.
So, either install a tang or use the Ironwood special stock.
