TM ak47 low FPS

[Dart]

Hey guys, I bought my TM ak47 about a month ago and thought it was working fine, that was until I actually fired someone elses gun, than went and cronoed it. Its shooting at 220-230fps with .25g BB's

this seems super low to me considering most people seem to be shooting around 300 with stock internals. The gun is 100% stock and has a foam bottom to the box *so its a newer release*.

There are a few gun docs out here but all of them seem super busy and I would not mind taking a whack at this my self for fixing it. I like to know how things work.

So what should I be looking for? I have heard and read everything from a bad nozzle to a compressed spring. Anyone have any tips in how to reconize these problems?

Also any tips on when taking it apart, and how do I reshim. I will be watching some videos on mechbox.com and following there procedures.

*FYI a stock TM that can barely go through one side of a can makes me cry *

[Skladfin]

That should be firing around 260~270 FPS with 0.20g BBs. So that is pretty normal for a TM gun.

Hope that helps

[Dart]

really? I was expecting more out of it... every other tm I have seen has been around 350 with .25g with minor upgrades.... so with a few upgrades I can add more than 100fps?

Also I should add when I fire in single fire there is kind of a...click clack it sounds like a bolt getting slapped backwards but its not from where the bolt is, you can kind of feel it in the grip. I can take a video if that helps.

[mattman2523]

maybe the motor is not adjusted right?

[lemegacool]

stock tm IS shooting low... why do you think they are reliable... your fps seems pretty tm-standard. if you want approx 350 thow in a prometheus ms100 spring. and for the other problem ... anti reversal fucked-up maybe?

[Dart]

I am looking at a m120 spring *someone out here has one*. Any idea where that should put this for FPS? will I end up stripping gears with it?

So the reliablity of a TM is like having a sports car but never taking it over 2500RPM?... thats not reliability thats just running under the thresh hold. anything will be more reliable that way.

edit for the motor adjustment where is the screw on the v3? Sorry I am new to this lol. Mind as well try that first.

PS I know I could end up breaking something trying this my self, so please don't mention this :P

[lemegacool]

Originally Posted by Dart

I am looking at a m120 spring *someone out here has one*. Any idea where that should put this for FPS? will I end up stripping gears with it?

So the reliablity of a TM is like having a sports car but never taking it over 2500RPM?... thats not reliability thats just running under the thresh hold. anything will be more reliable that way.

depending on the brand it should shoot between 400-420 witch i really too hot for gaming... your best bet is aroung 380 fps like a prometheus ms110

[Dart]

people in kelowna are a bit nuts... our field limit for aegs is 425 with .20g.... not saying I Need to hit that, just saying that we play a little hot out here.

350 would be nice cause I do not want to do a bunch of internal upgrades. How hard is it to install a new spring? Would you recommend leaving that to a gun doc?

[Crunchmeister]

Go to www.mechbox.com and watch the AK videos. You'll be able to see for yourself how hard it is. A spring upgrade is pretty simple, but you'll also want to upgrade to metal bushings as the stock nylon ones don't hold up well to heavy springs. That will also require you to reshim the gearbox.

[yuhaoyang]

after a TM hits around 330 with an upgraded spring, it will(theoretically) require metal bushings, around 370ish it should(theoretically) have a good spring guide, reinforced gears, and a good cylinder head. A sorbo is a very good idea as well since the mechbox shell isn't reinforced. Although I've heard that "samuel" on EAR pulled off some witchcraft and made a stock TM shoot 340 with no aftermarket parts. It also seems some people have run high(er) spring powers on a TM with mostly stock parts, and they've run in to no issues.
Don't bother adjusting the motor height, since there isn't really anything wrong with it. Changing from .2 to .25 is equal to around a loss of 30-40fps.
Opening a TM when you havn't really opened a mechbox can lead to a world of headaches... I've done that before, and it was a pain in the ass... Well, if you still want to open it, good luck!

[ancorp]

What in the world does motor height or the AR latch have to do with velocity?

The last TM AK I owned was a TM Alpha Spets. It was stock, except for a 400fps spring, a tightbore, and metal bushings. Had seen thousands upon thousands of rounds and everything still looked mint inside. Yes - stock piston, stock gears, stock motor, and so forth.

[pusangani]

Originally Posted by ancorp

What in the world does motor height or the AR latch have to do with velocity?

The last TM AK I owned was a TM Alpha Spets. It was stock, except for a 400fps spring, a tightbore, and metal bushings. Had seen thousands upon thousands of rounds and everything still looked mint inside. Yes - stock piston, stock gears, stock motor, and so forth.

lolyup the blind leading the blind

[Dart]

Interesting. i did not realize .05 of a gram took the fps Down so much. and i understand about the upgrade thing. some people get lucky with stock parts. my plan was to leave the gun as stock as possible. upgrading is a domino effect that can get expensive. i just hate getting out ranged by everything on the field. is there any way to get more range with our fps? Will a tight bore barrel add any or is that just accuracy? the other noise still worries me. video coming tomorrow.

[Mitchell12]

Tight bore's tend to help you squeeze out a little more range and fps but it's not a great way to improve it. As you said it's more about accuracy.

[m102404]

There's a couple of great articles out on the 'net about tightbores...I won't repeat it all here aside from there's not a whole lot to be gained for general/regular field usage with anything tighter than a 6.04/6.03mm tightbore.

Personally, I think tightbores in "little" guns (i.e. MP5/AKS') are a waste of money...but hey, it's a hobby and do whatever makes you smile.

Stock TM's are reliable out of the box. Their parts are balanced for the power level. Just as you'd never drop a 400HP engine into a 100HP car without considering the transmission, brakes, tires, etc....you can't just drop a more powerful spring in and expect the stock parts to hold up as well (this is a bit of an overstatement to get the point accross).

From a stock TM AEG, consider the following for reliability (R), performance (P) and accuracy (A). Read up on the Stickied posts about "What to upgrade...and why"...they're there for a reason.
- metal bushings (R)
- shimming (R)
- greasing (R)
- spring guide (R)
- bearing spring guide (P/R)
- gears (R...at higher power levels...but they're not always needed)
- tightbore (P/A)

With a "clone" there'd be a lot more to add to that list.

If you run your rifle somewhere between 370-390fps w/0.20...your internals/battery/motor will thank you for it. With most common upgrades (listed above) you get that with maybe a M100 or more likely a M110 spring. It's not impossible to get mid 380fps with just adding a bearing spring guide, a quality M100 spring and a 6.04mm tightbore to a stock TM AEG (carbine or regular length). But a lot depends on how well the compression of the whole system is...it is an airgun after all and air leaks will kill off power faster than anything else.

Run a M120 if you want (it'll put you in the 390-430 range depending on what other upgrades you do). Be prepared for anything but either brand new quality mini batteries or large batteries to die off really quickly. Also be prepared to wear out your internals much quicker (kicking off that never ending parts replacement cycle).

Just because the field MAX limit is over 400...doesn't mean you have to shoot at that power level. The extra 10-20ft that you'll pick up in range is easily covered in 3-6 big steps.

Best of luck,

Tys