It would depend on how the buffer tube is attached to the receiver. I could not find any information regarding that rifle and the stock adapter. I recommend contacting Sig Sauer in regard to a compatible folding stock adapter.
Yes, the DoubleStar Push Button Folding Stock Mechanism w/o Boss includes the socket head screws (#10-32 × 1/2”) required to install the mechanism.
The DoubleStar Push Button Folding Stock Mechanism w/o Boss might work for a PSA AKV9. However, I recommend contacting the manufacturer to confirm compatibility.
Yes, the DoubleStar Ace Push Button Folding Stock Mechanism Without Boss will work with a Zastava AK47.
Yes, the DoubleStar Ace Push Button Folding Stock Mechanism Without Boss should work with a RAS47.
Yes, it should work on the WASR
It will likely work, but you need to make sure to purchase the correct receiver block. You can get the correct recommendation for receiver block direct from DoubleStar here: Phone: (859) 745-1757, (888) 736-7725
It will likely work, but you need to make sure to purchase the correct receiver block. You can get the correct recommendation for receiver block direct from DoubleStar here: Phone: (859) 745-1757, (888) 736-7725
If the receiver block is set up to accept this style of folding mechanism then sure it will fit. In regards to a brace, you would realistically need to use the folding adapters that are set up to accept an AR receiver extension instead of this style of folding adapter.
These are meant for AK pattern firearms and cannot be guaranteed to work with a Masterpiece 30T.