[CDN_Stalker]

I've been working on a new guy's CA M15 for at least 6 hours now (8 or 9 if you include the hours I worked on it after I got it) and it's pissing me off. max velocity I've gotten out of it has been 312fps with a Madbull 110 spring (same as in my MP5SD, which is a 400fps gun), and the lowest is 49fps.

Piston: Some smoked semitranslucent polycarb piston, initially found it was binding ont he mechbox rails.

Pistonhead: Some alumimum ported head, seems the groove in it is to wide and air from the ports escapes behind the O-Ring.

Spring: Came with a Prometheus 110 spring.

Tappet Plate: Some yellow plastic one.

Cylinder head: Some purple aluminum one with the tapering inside like it's meant for a silent pistonhead.

Nozzle: Some brass tapered one, airseal type.

Cylinder: Chromed steel with ribs (for her pleasure?)

Hop up rubber and unit: Brand new Guarder with an odd clear rubber, which has breech lips longer than most rubbers I've deal with, explains the serious plugging, feeding 1 BB out of every 8-10 shots. No amount of oil helped.

So, I've swapped out and tried parts I have sitting around, nozzle, various hop up rubbers, various piston heads (including a Systema silent one) with different O-rings, a Modify ported head, a Deep fire ported head, even a stock TM head. Nothing does anything any good, either gets worse or stays the same. Just tried it now with the owners parts in it, and a Prometheus 120 spring (put out 435fps in my MP5) and I'm getting 150-165fps out of it. Am really at a loss right now, going to have to contact the owner and see where he wants to go. Thought maybe I'd pull out some of the stock TM parts in my MP5SD (is shooting to close to 400fps for my tastes) and just trade him them, give him at least a shooting and reliable gun.

Now I can see why the owner sold it, too many mismatched parts, too many problems. Is obviously an airleak somewhere, and I thing the best thing to replace would be the cylinder, since it seems the pistons aren't getting enough initial compression to inflat the O-ring properly, but I only have an MP5K cylinder to try currently, but that'll cause suckback, so I don't see it as a good test part. Also wrapped the cylinder head's O-ring with teflon tape since I found no piston head put out compression even with no nozzle on it. Got a couple pistonheads to give varying amounts of compression, some very good compression, but never when actually shooting the gun.

Sigh!