I built one on a 1894 Brazilian contract small ring action made by FN. When I got the kit I was disappointed in the barrel for 2 reasons. One was the contour looked like it had been done by 2 guys. One starting at the muzzle and the other at the breech. There was this small whooptie halfway along the length. Second was that while the grooves appeared nice and smooth, the lands looked like they had sawteeth!
I turned out the whooptie on the barrel so that problem was gone. And VERY unexpectedly was the way it shot. Superbly! I shoot cast 90% of the time and this thing was a shooter, par excellance.
The rifle:
Tee other parts in the kit (Follower) was plastic, and the spring was simply the spring out of a magazine body (apparently). Finally the spacer block was simply a mildly shaped piece of white nylon. They all worked just fine.
I didn't like the plastic follower so it got tossed and I cut down the original steel one. I then soldered on a piece of brass to take up the windage between the original 7x57 and the smaller 7.62x39 case OD's (30 Rooski Shortski). The supplied plastic one works great, it just went against the grain.
You can see the spacer in the photo. It WILL move forward under recoil and tie up the ammo/follower. Drill and countersink a hole through the rear of the magazine housing and simply screw in a wood screw. That takes care of that.
Another modification I recommend is an extension on the ejector (see photo). It's originally designed to eject the much longer 7x57 case. The shorter one can rebound back into the action, or get sideways jammed under the action bridge. The extension finger prods it out of the boltface earlier so it clears through the ejection port without issue. I made no mods to the extractor as it works fine, yours may not. If not too bad
. You have some welding and grinding ahead of you. I did nothing to the boltface.
I jeweled the bolt, added the rear apurture sight and MiG welded on a new bolt handle. The barrel I got from Gun Parts was very tightly chambered. All I did was to screw it on the action. On the breechface in 1/16" numbers it is stamped 7.62x39. The raised metal from this caused the bolt to drag so I had to polish off a bit of the face of the left (long)lug.
Since these barrels are cut .300x.308 I do not recomment you shoot any surplus or factory ammo loaded with .310/.311, or .312" slugs. Especially not in an older small ring action. Some load data shown for the 7.62x39 shows pressures in excess of 52K. Couple that with a slug a few thousandths over groove and you may stress something. These are only recommendations. I don't want ot get involved in the relative strength merits of the small ring vs large ring actions. Suffice it to say I would not barrel a surplus large ring 98 type action to 300 Win mag either, as is commonly done. Just me.
Rick