Apaches, my short version. Do they work? Yes. Do they blow my skirt up and make me want to convert everything to them over tappet plates? Nope.
They don’t do anything that a tappet plate can’t, except they can’t use less than ultra hard gels. They are no easier to setup than a tappet plate imo. They are basically a trade off, and for best results require the aztech tpiece which really bumps the price to nearly $115!
One hand you can with their extortion priced tpiece adjust it easily til it is consistent feeding and sealing. But where it makes that easy enough, getting the right nozzle length with any other tpiece is a bit of a stuff around. Fine if you do heaps and know how many orings to space the tip forward but they are a bit annoying to setup.
I used one recently on a SLONG gearbox, which is tough af, but it is an A/S box, which just didnt have the nozzle travel to feed and seal, it was one or the other. So, the apache is in it and in this scenario it is perfect. I suspect retroarms boxes would be similar…
I could have dremelled the tappet runners to allow travel and a wells tappet, but that isnt ideal either. The apache was a godsend for that gearbox.
If your setup with a tappet plate needs “x” long barrel, with apache you will need “X minus 20-30mm” So longer barrels get a bit shorter. They are perfect for shorter barrels, with short stroked gears and bigger springs (m120, short 4 teeth, still got 350fps like my tappet setups did just with 20mm shorter barrel). With lesser springs they tend to be less consistent, and can have a bigger effect one volumes, making it a bit more trial and error to get the desired results.
But otherwise, in a gel gearbox, that has the tappet travel to feed and seal, and if you are busting over 25rps, just trim a couple mm off the tappet plate and shorten the return spring by 2 loops… or 30rps or more, trim a few loops off a good tappet spring, and trim the tappet tail to just above the sector gear shaft and boom, 40rps and up feeding and sealing. For most of my work, 25-30rps, this nearly always works.
And if your reason for getting one is my return springs keep breaking, get better quality ones, and put a bit of silicone paste on them. I have return springs that have lasted through hell for nearly four years. And honestly, I rekcon you will have to open the box to lube the apaches internal orings more often than any return spring breakage probability.
I wouldnt put them in something unless it needed it, like my SLONG box did, and my cyma while it worked I ended up changing it back to a tappet plate setup, because it was more consistent on semi and auto, where apaches in full auto tend to have a bit more fps than semi for some reason.
Good on them for attempting innovation, and it has it’s uses, I certainly won’t rag on them for it. I currently own 2 apaches, and only one is in a blaster. The other is a “maybe one day”.
For those wanting to know, the SLONG is an awesome option for a wells If you busted your box, but you will need a apache, and their tpiece ideally, and it was fussy to setup, (bushes had to be glued in, the spring retainer uses 4mm bolt instead of 5mm, and most cylinders need to be filed down to fit properly by a fraction) and you will convert to gen8 style mags. Apart from needing ultra hard gels, it is a great tough af box. Also mine is not in a wells, it is in a “thingy” bitsa that I slapped together. Kublai receiver, with bits from god knows what!
it’s a Spina Optics LPVO, low powered variable optic. Used a lot on DMR real steel, not holo or red dot reticule, actual crosshairs with a zoom range that’s a bit more gel blaster friendly. Eye relief’s at the fat end. 
