I am wanting a 10 round spring feed, but it is for a marker that isnt a spring feed, so I want to know can these be brought separately from say a phantom(or other stock class) pump? Also are the universal an just attach to a standard feedneck?
The normal feeds on phantoms aren't spring loaded (in fact a spring feed isn't allowed in stock class). The phantom stock feed replaces the feedneck and if you wanted to fit one to another marker you'd have to take the feed neck off and thread a hole in the body for the screw that holds the stock tube on.
However if you just want to hAve a stock style feed with your existing feedneck google DIY stock class feed and look at the mcarterbrown results.