Need some info on the Vector v53

I am in the process of buying one from a buddy and really can’t find a lot on line about them.

It is the short barrel with model with the really long funny looking extension. I plan to SBR it, that stupid looking FH or what ever they want to call it will be going bye bye.

What is the thread pitch on these and does anyone make a thread adapter to change it over to 1/2X28 so I could use an M4 suppressor on it? It is just crying for a good one and now that they are legal in MO. I will get one for it.

According to the current owner(it has had two and I know them both) it was not reliable with a collapsible stock attached. I don’t know what he means exactly or what it was doing, but how would the stock affect the reliability?

Anything else I should know about these?