I think this ought to be a commonly asked question but I searched google and airsoftforum.com and couldn't find any recent specific information, so...

I just bought a G&P m4 on evike, the full metal with collapsible stock: http://www.evike.com/product_info.php?cPat...oducts_id=37369

I'm just wondering what battery I should buy for it? The website says "8.4v Small Butterfly Type" is recommended, but I see no mention of the "butterfly" configuration on cheapbatterypacks.com custom battery maker. I'm also skeptical about 8.4v being enough voltage, as my GR25 with stock spring wouldn't cycle with the stock 8.4v battery (had to go to 9.6v).

Can someone who has handled this version of the gun speak to how much room there is in the battery compartment?

And I think I should probably go with a 9.6v or 10.8v to pull what's probably a stock ~M100-M110 spring with a M120 motor?

Thanks!

You would run a crane stock or nunchuck battery such as http://www.evike.com/product_info.php?cPat...oducts_id=24476. The battery is also a deans connection as it says on the product description; don't buy batteries with tamiya plugs! Its still a standard size battery. About the spring not cycling, was your battery charged? A 8.4 volt should run fine; however a 9.6v is still preferable. You may need a mosfet to run a 10.8v battery.

Thanks for the quick reply. I did see that it is Deans which is awesome!

Yeah the battery was charged. It might have just been that the stock battery had a low discharge rate or something, I don't know. On that note, I just dropped a M120 spring into that GR25 and bought a G&PM120 motor for it, along with a 10.8 battery to try to increase the crummy trigger response... Maybe another case of me not doing enough research beforehand - I never really understood what a mosfet was or why it would be needed. I did a bit of research just now and it seems like there is conflicting information - some people say you need it for 10.8 and some say they've been using 10.8's for years with no issues. I suppose I can always just wait for the trigger contacts to give out and THEN buy one, or open up the gearbox after a bit and see how the contacts are holding up / clean them if need be.

As for the M4 battery, 9.6v it is then, I guess. I honestly would prefer a lower RoF than it will probably have anyways for the sake of realism and conserving BBs. I was mostly just worried about the battery fitting, as I had to go for the 4/5sc batteries with my GR25... I would love to the use the sc sized 5000mah elite batteries but that puts the two longer columns of batteries at 5.1 inches. I'm just a bit worried because it says "small" butterfly is recommended. However, "butterfly" appears to be a nunchuck configuration whereas crane stock has 3 stacks of batteries, allowing it to stay shorter for the same amount of batteries.

Yup. I have an crane stock SPR carbine and an Intellect 9.6v 1600mah nunchuck and it works perfectly, albeit it needs a plastic holder to make the battery not jiggle in the stock. I care, because I have like OCD but its not a major issue, especially if your gun came with the plastic holder already. Also, a mosfet is a circuit that lets your gun use power more efficiently and is needed on higher voltage setups or on lipo setups. Small battery means small tamiya plug. No idea why they wrote that on a gun wired to deans though...