demon.b Posted February 22, 2008 Report Share Posted February 22, 2008 Got my CA M249 Mk 2 running earlier today, tried an assortment of springs to see what fps could be achieved. I'd like to know from other users if they get similar figures or if I need to do a bit more work on airseal/compression. Gun spec: standard cylinder, cylinder head & nozzle, CA piston with 2nd & 3rd tooth cut down, Guarder POM piston head, CA 6.04 barrel. Spring FPS Standard Marui linear 255-260 Standard CA linear 310-315 Guarder SP100 non-linear 340-345 ?M110 or ?1J non-linear(in the gun when I got it, not a standard CA spring as far as I know) 300-305 Now for some oddities: Prometheus MS100 non-linear 260 (yes 260) checked this twice, put it in, took it out, tried other spring, put it back. Duff spring? Doesn't feel abnormal compressing it by hand, can springs be duff? Weaker grade spring in wrong packet? PDI 130% pro linear 375-380 (Too close to 1.35j for my peace of mind) PDI 140% linear 350-355 Again checked this twice to make sure I hadn't mixed them up. I thought the higher % meant higher fps, why do these two seem back to front? Does the 'pro' label mean anything? (There's nothing on the UNCo webby to indicate a difference). Thanks for any help. Link to post Share on other sites
Benson Posted February 23, 2008 Report Share Posted February 23, 2008 Some very interesting results you have there, but it seems like for the most part your 249 is shooting at what it should be. However, I can only base this on my experience with Guarder springs. With an SP100 I get 300-310, and a 110 (which is what I usually run) I get about 340ish. Mine might seem a little low compared to yours, but I attribute that to the fact that I haven't done any maintenance on my 249 in nearly 2 years, aside from clean the barrel now and then (still on stock piston too!). I'd clean out all the dirt in my gearbox that I'm sure is covering everything, but I don't want to let out whatever voodoo magic is keeping this gun shooting so great for so long. If you're still worried about air seal, I would swap out the nozzle to one with a more rounded end. The notched end in my old CA nozzle got me some lower and less consistent FPS readings. I switched over to a Systema nozzle + Systema 6.04 barrel and my FPS issues went away. Link to post Share on other sites
k30dxedle Posted February 23, 2008 Report Share Posted February 23, 2008 I (think) the PDI "Pro" springs are longer, and meant for the PSG-1 V4 gearbox. Link to post Share on other sites
Sale Posted February 23, 2008 Report Share Posted February 23, 2008 A standard Marui spring should give you 280-290 fps even with a slight leak (like Marui has, because their stock system isn't airtight). Based on this I'd at least check the system for air leaks. Link to post Share on other sites
sadigh Posted February 23, 2008 Report Share Posted February 23, 2008 CA M249 springs are longer than regular TM springs. Link to post Share on other sites
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