How hard is it to install a scope rail on a milled Arsenal SAM-5? Who would your recommend to do it and what rail to buy? Thanks.

I have a SAM 5 comming tomorrow from Impact Guns, and a PK-AS-S scope from Tantal.  Found a bolt-on sight rail local, and intend to follow instructions on Tantal site.  I'll let you know how it went, and rail source when I'm done.

Got the PK-AS-S scope installed  on my SAM 5.  The sight rail I found locally was not an exact match to the scope mount. There was about 4 hours of hand fitting to make it fit, because the male dovetail was too large to slide into the mount.  I also had to countersink the rear of the bolt holes deeper so that the shoulder screws would tighten through the side of the receiver. The correct one (not in stock) is shown on tantal.kalashnikov.guns.ru/bstmounts.html . It is the MKT01 with shoulder screws, and has excellent installation instructions further down the page.
The scope is great.  It mounts slightly to the left of center, allows use of iron sights, allows empty shells to clear without extra scope height, and allows someone that sights with left eye to shoot from either shoulder with a good cheek weld to stock. Sight with right eye, shoot right hand only.   If you are interested in the slightly incorrect sight rail, PM me, and I'll give you the source.  Cost was $25.