m4 and m249 upgrades?

Hey guys i was looking for some upgrades for my classic army m15a4 carbine and a&k m249 saw. i would like the fps to be 350-380, and to increase rate of fire. oh, and to get rid of the whiny high pitched motor. any thoughts?

Yea go check out rhino at Airdog Airsoft he will be there wednesday and thursday he will take care of your high pitched motor and your upgrades.

A good shim job is going to be the best thing you can do to reduce gearbox noise, especially in the SAW because A&K stock shimming is either horrible or nonexistent most of the time.

For the CA, I'd get an M115 spring and reshim/grease the gearbox, and a 7.4v lipo/9.6v nimh and/or a Matrix Magnum.

For the SAW, I'd get an M120 spring and reshim/grease the gearbox and the same for the battery and motor.

If you don't know how to do a propper shim job, then I'd recommend taking it to Airdog and having them do it.

you cant run an m120 in a saw if you do you will get extremely low fps. you must run at least a m140 to get 400fps due to the fact that the piston does not travel the full length of the gear box.

Yeah like trent said, a 140 for the SAW and 120 for the M4, plus a piston and decent shim job.

You might want to get a tight bore barrel too, it helps with the accuracy and makes your grouping a lot better.

superchrisguy wrote:You might want to get a tight bore barrel too, it helps with the accuracy and makes your grouping a lot better.

Actualy in most cases tbb's lower fps and do not increase accuracy to a point to where its noticible. I would just keep your stock barrel and get a madbul blue bucking.

Admin wrote:A good shim job is going to be the best thing you can do to reduce gearbox noise, especially in the SAW because A&K stock shimming is either horrible or nonexistent most of the time.

For the CA, I'd get an M115 spring and reshim/grease the gearbox, and a 7.4v lipo/9.6v nimh and/or a Matrix Magnum.

For the SAW, I'd get an M120 spring and reshim/grease the gearbox and the same for the battery and motor.

If you don't know how to do a propper shim job, then I'd recommend taking it to Airdog and having them do it.

what exactley does shimming do?

essentially inside your gearbox there are gears that don't quite match up to each other. Shims are put in place to make them mesh better. This helps them move freely and with less noise. Shims are just thin metal discs. Sounds easy but it's like taking a puzzle (your gearbox) and then adding all the pieces to another puzzle and putting it all together. Definitely something to have a gun tech do unless you are knowledgeable.