The kit is 275 and the Kalushnapup is a stock, not considered a pistol grip. From the FAQ part of their website, under legal,
Does it require a license or permit?
No, it’s classified only as a non folding shotgun stock. There are no federal permits, regulations, fees, associated or required of this part. BATFE has counted it as 2 US made parts- Stock and Trigger. Adding as many US parts as you like to your Saiga-12 is legal.
Interpretation – A “fixed” non detachable 5 round magazine in combination with pistol grip is Connecticut legal. The classification of Kushnapup is neither as pistol grip nor thumb hole stock, in regards though it is a “rifle stock, possibly pistol grip” which minimally is legal under Connecticut law in combination with “fixed” non detachable 5 round magazine version of RAA Saiga-12. Use with detachable magazine is subject to legal interpretation which is yet inconclusive if using “fixed magazine” bullet button device legal in California.
Does it require a license or permit?
No, it’s classified only as a non folding shotgun stock. There are no federal permits, regulations, fees, associated or required of this part. BATFE has counted it as 2 US made parts- Stock and Trigger. Adding as many US parts as you like to your Saiga-12 is legal.
Interpretation – A “fixed” non detachable 5 round magazine in combination with pistol grip is Connecticut legal. The classification of Kushnapup is neither as pistol grip nor thumb hole stock, in regards though it is a “rifle stock, possibly pistol grip” which minimally is legal under Connecticut law in combination with “fixed” non detachable 5 round magazine version of RAA Saiga-12. Use with detachable magazine is subject to legal interpretation which is yet inconclusive if using “fixed magazine” bullet button device legal in California.