SACair Forum

i have a tm m4a1. upgraded the parts so it shoot reliably at about 390FPS but it only cronos at 350/360. this is what i have.

what brand BB's are they?is your barrel clean?TB barrels require more cleaning and maintnence since the inside radius is smaller.Even the smallest piece of debree(sp?) can cause the FPS drop..clean your barrel and crono it again

Stop relying on charts.

[quote="neouser"]Stop relying on charts.

i bought a display model so im sure it was shoot a lot by people who didn't buy it... but the barrel is clean and everything is air tight im sure. and im not relying on the charts its just that if 4 different charts say 380-390 im sure it should be pretty close right?

Diryt barrel, bad hop, bad o ring in the piston. thats a good place to start.

ok. so whats the best way to clean the barrel? someone said they use a .22 cal cleaning kit? let me know, thanks!

the TM's came with a cleaning rod.you place a piece of napkin through that little 'hole' and push it down your barrel.

id use a kleenex; they are far softer.

You don't want something that will possibly put any dust or debree in it. I recommend 100% cotton shirts, any old one just cut it up. I cut up one shirt into about 10000 pieces +, or you can just go to any online gun shop and order a bag of swabs for...3-10 bux. Napkin and Kleenex leave fibers inside the barrel sometimes.

also put some gun cleaning oil on it JUST a tad, not silicone, like valve oil for instruments, or gun cleaning oil. so u actually pick up all that crap in their, then run a dry cloth through it a few times until u get all the oil out.

TMs in general have very good compression but air leaks are common. I do agree with your set up given, you should be well over what you just chronoed.

+1 that sounds like more comression than dirty to me. Take out the pistol and cylinder assembly, put all together as how it should be in the gun including the nozzel but put the nozzel on the little tube thing off of the cyclinder head. Then put your finger over the hole in the nozzel. Then start working the piston back and forth. How easly can u push it back front? if there is good compression it will be really hard to push and pull back. If there is no compression lube the oring around the piston head lightly! and the seals in the cyclinder set up. Then try it again. After that is done come back here.

word son! thanks guys, ive done all listed above but dont have a chrono, sooooo im going to try to get to AEX today, (having the same day off as the g/f normally mean im locked down) haha but maybe i can take her to some place she likes in sac to make it fair :roll: but ill let you guys know whats up. thanks again.

you are chronoing it with the hop up completely off right? some people forget to turn the hop up completely off.

well just got back from AEX and with hop up on its at 380 so everything is good, thanks guys!

Sweet good to hear we actually helped some one out!