Optimal Gear Ratio

So I’m building a gearbox for a m249, assuming the gearbox is nylon shell and metal components, what what be the optimal gear ratio to achieve a maximum rate of fire, without putting a huge amount of strain on all the components, also while running a 1.2 - 1.3 spring to also get the most out of the gels before the fly everywhere but where your aiming. I’m guessing 18:1 or 16:1 at the lowest but I really would have know clue, or is what I’m asking of the gearbox too much? Cheers.


What you are suggesting, 16 or 18 to 1 and a 1.3mm spring, sounds good to me. Chasing massive rates of fire, if you are not sure what you are doing, can make for a very unreliable and short lived (between repairs) blaster…

As you have outlined is a sensible way to achieve a good, spray all day blaster that doesnt empty mags like they are going out of fashion :+1:


Thanks for the response, I wasn’t aiming to go for dumb fast rates of fire. Do you think a 11v battery will still go okay in it?

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You can try, the worst thing that may happen is the gears may strip and you will need to fit metal gears. There is no real way of knowing if 3S will work, or for how long unless you try it.

You can always get another Gen8 nylon gearbox in case the gears strip, you can right away fit the spare box, then upgrade the original that stripped. Just remember the SAW has a long trigger that isn’t available as a spare (not that I have found)pop

If you do, and you succeed…

Your next consideration will be sorting out a much larger mag

I have a Kriss run up as a stinger on 16:1 and a SHS HT motor.

12.5a current draw and a mag dump in under 5 seconds

It’s a problem in itself

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The SAW has the big box mag… much better than the normal mags… even on 3S it should last at least 57 seconds … just need to be able to find extra mags :+1:


OR, carry a couple of speedloaders (I just use a wide-mouth 750ml water bottle).

That big loading bay means FAST refills :wink:

you are still a ■■■■■■ cushion whilst refilling…just sayin…

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The 249 has a gen 8 box so is already running 18:1 gear ratios. you should be able to push to 16:1 no problem. My 249 is running a stock setup with 11.1V and shoots all day long. Next update is a 45cm alloy barrel and 1.3mm spring.

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