I've had time to reflect on good advice I found here. The Fury 1 upgrade is essentially in maintenance mode now, and is shown in the pic with a Bulgarian AK-74 (No-Dak Spud) for reference and size comparison. It weighs about 9.5 pounds by my guess. I should go weigh it, but I was already used to carrying an M-60 back in the day.
I've tried many loads and it is rock solid with all the slug or buck I can find moving faster than 1250 fps. I did adjust the set on the TAC-47 a bit for more consistent performance with a magazine of mixed manufacturer's ammunition. That was about 1/2 turn in (righty-tighty). From 1250fps to 1600fps I've seen no performance issues. The TAC-47 does exactly as-promised, and well. Extraction and Ejection are consistent and clean. Recoil is positive but not harsh: it is more a long impulse stroke. Oddly, it really shoots the Olin milspec buckshot very well. That is commonly available here in the Academy Sports stores @ $4.99 for a box of 5. Good plinking and HD ammo.
I have not tried any shot yet, but after another 50-100 rounds of solids, I 'll see what the TAC-47 can do. I'd like to know how BB and 4-ought performs for curiosity, but the house load is buck.
The scope is an inexpensive 1-4x (good, not great) with a Chevron "ballistic" reticle. At 4x, the optics are clear and sharp, and the objective can be adjusted for focus. I can hit 8" plates at 75 yards 5/5 from a rest or prone. I have not adjusted to 1x to check POI change- I leave it in 4x for distance work. If I change ammunition, I can use the chevrons consistently to hold over for the slower ammunition, as I zerod the gun with the fast Winchester 1620 fps slug. This gives a decent 50y zero, and POI is about 2.5" low at 75y. I have to lift off the cheek weld slightly to use the scope as-shown. The straight bore/stock line makes that painless, but less precise I suppose. I have not zeroed the iron G3-style sights yet, but they are easy to see through and probably good for buck at household distances.
We did some initial smoothing of the bolt/carrier assembly per your instructions here. I may go back in and smooth any nicks I find at 500 rounds. So far, the gun has not shown any metal distress.
Most if not all of the kit is from CSS
The stock and grip are Magpul from my local guy
The fixed sights are Chaos, mated to the OEM and handguard rail sections. They are below my plane of view in the scope, and the QD on the left side of the scope lets me ditch it quickly for iron sights.
Failure- at about 150 rounds service, the gun failed to Extract. It was locked up, so I cleared the magazine and carefully ran a dowel into the muzzle and determined I had an empty husk on the breech. I fidgeted a bit, and then realized that tilting the gun resulted in some rattling in the gas block. I removed the TAC-47 and discovered the CSS puck had failed into three pieces. My gunsmith picked it out carefully: there was no internal damage to note, but he did flap the gas tube lightly. The puck appeared to have suffered a material failure I'd associate with a grainy casting. They sent me a new one quickly, asserting I was first of a kind. The new one has a different surface appearance overall compared to the original. I have another 100 rounds through it without any FTEx/FTE. Changing the rock-n-lock magazines is not fast, so I am not convinced it's a 3-gun candidate. Even my 1980s vintage 1100 is faster. The gun is smooth to shoot for a long session. And if I get the chevron holdover right for 200 yards, the sound of hitting a metallic silhouette ram with a big slug is very satisfying! I've been traveling a bit, but I appreciate the good advice and coaching I got here. I now have a hankering for a Saiga in .410. Help me, Obi-Wans. And thank you, again.
Hm- pic did not "attach". I'll go figure that out. My apologies.