TM M4 Aim Problem

[jareyes]

Hey guys, hate to post this as I'm sure tons of people have asked about it, but everything I've read so far I've tried and no luck.

This is my problem in short:
My gun ALWAYS shoots hard right, no matter what I adjust. It also ALMOST ALWAYS shoots low, except Sometimes when I adjust the hop-up, sometimes when I adjust the sights/scope, it's really hit-or-miss.. quite literally.

Basically, I have an original version TM M4 bought second-hand, but the seller made me aware of all issues. He changed the 110spring to a 150spring without changing the hopup rubber, so I changed it to one that was suitable for 130-150. I also noticed the original barrel was bent a bit so I bought a new one (tightbore too) and installed it today, shot again, no difference.

After that, I switched back to sights (I was using my ACOG scope) because I wanted to deduce if it was because my scope was wonky, if my sights were wonky or if it was something internal. With ironsights, it still shoots hard right and low...pretty much the same as any other shot. Switched to left-handed shooting to see if it was shooting right because of my technique, still the same. Not really sure what else is possible here, if anyone's got advice I'm welcome to try anything short of buying a new gun. Who knows though, in the end I just might

Thanks in advance for any advice.

[M4]

Is the inner barrel the full length of the outer barrel? If not the bb could be hitting something upon exit of the inner barrel.

[jareyes]

Originally Posted by M4

Is the inner barrel the full length of the outer barrel? If not the bb could be hitting something upon exit of the inner barrel.

I doubt that is it. The first barrel I had in it (the bent one) still fit into the outer barrel, wasn't a tight squeeze, and ended where the flash hider started which is how it's supposed to be. Now this second one I have is probably 1cm short of the flash hider, but when I bought it from Huang he said as long as the hop-up placement is good, which it is. I believe him. I am one puzzled guy.

EDIT: Sorry, I also forgot to mention in the OP. I HAVE tried different hop-up settings (obviously haha) and that doesn't seem to work either. I also noticed that after buying the tightbore, my GROUPINGS are excellent, very excellent in fact. The only problem is that the placement of the groupings is still low and to the right. For example: If I aim at a bullseye target, it will be in the lower right quadrant of the target, but consistently in the same area.

[Nova316]

If u have tight groupings on one area then try to adjust your iron sights, also check what ACOG u have, if its an older one it might not be adjustable

[jareyes]

Originally Posted by Nova316

If u have tight groupings on one area then try to adjust your iron sights, also check what ACOG u have, if its an older one it might not be adjustable

Tried playing around with the iron sights, moved the rear one a little left and I found the shots were placing more centre (on the target I mean), but still a little low. So I adjusted the hop-up to compensate but as soon as I adjusted that it started shooting hard right again.

Also, I bought the ACOG from Huang like maybe two weeks ago. Not sure how I can check if it's an older one or not.. it's a replica fo sho though. *shrug* it's the one with the doc sight? If anyone knows anything more indepth about Huang's products. Also not sure if it being a replica affects the fact that it can be adjusted. Which would explain a lot, I tried dialing the adjustables (horizontal and vertical) to as far as they would go either way, and cranked either way it still shoots hard right and low.

[zone 69]

Try taking off the flash hider and trun the inner barrel a little and I mean a little to the left or right untill it shoots on target.
For the BB droping down trun your hopup up little by little untill it brings it up to where you want it. To little hop the BB will drop to much hop the BB will go up.
Then once you get the BB flying true ajust your sights&ACOG to the BBs path.

Let us know if this works for you.

[jareyes]

Originally Posted by zone 69

Try taking off the flash hider and trun the inner barrel a little and I mean a little to the left or right untill it shoots on target.
For the BB droping down trun your hopup up little by little untill it brings it up to where you want it. To little hop the BB will drop to much hop the BB will go up.
Then once you get the BB flying true ajust your sights&ACOG to the BBs path.

Let us know if this works for you.

Will try this as soon as I wake up tomorrow. Thanks for the advice, will let you know how it goes.

Also to the other two that posted earlier, thanks for your suggestions even though I had done them already. Really appreciate any and all input.

EDIT: So, I gave it a try and the flash hider is just too tough to screw off. The guy I bought it from gave it a coat of spraypaint and with the experience gained from taking apart the rest of the gun, that makes it super tough to take it apart. Will have a go at it again with some tools later on tonight but, in the meantime, does anyone else have any other suggestions?

[zone 69]

You do know that TM flash hiders have a CCW thread.???

[jareyes]

Originally Posted by zone 69

You do know that TM flash hiders have a CCW thread.???

If you mean that the flash hider is screwed on to the barrel ccw then yes. I just figured it was the spray paint because, as hard as it is to believe, the tension created by that layer on top is astounding..as experienced when disassembling the other parts of the gun. In any case, I gave it a go with tools and it's still not budging.. not sure how to go about it.

Nobody has any other suggestions?

[Nova316]

Did you remember to unscrew the small setscrew at the base of the flash hinder?
Hard right flight means you need to readjust your hopup rubber or you need to get a new one

[jareyes]

Originally Posted by Nova316

Did you remember to unscrew the small setscrew at the base of the flash hinder?
Hard right flight means you need to readjust your hopup rubber or you need to get a new one

Hey nova, thanks for the suggestions. At the base of my flash hider there is no setscrew, so I asked the guy if there was any particular way he secured it, he claimed he used epoxy. So I tried heating it up a bit to wear the epoxy then tried to unscrew it, no go =\. Like it's really stuck, I'll probably try malleting it a bit or something.

As for the hard right flight, I'm not sure what else to do for the hopup rubber. I've already just bought a new one (made for TM 130-150spring) and installed it, I'm pretty sure I installed it correctly assuming that correctly installed, the barrel and hop-up rubber are aligned so that the piece on top of the barrel assembly presses down into the barrel. I think there's even a groove for the rubber to follow on the barrel to make sure it stays there..

[Nova316]

there is but the little piece of rubber (nub) needs to be parallel to the front not perpendicularity even tho that way it fits easier

http://www.airsoftparts.ca/store2/im...rubber-set.jpg

The nub is that little piece of hopup rubber

What is does is when you turn the wheel it pushes down the hopup rubber into the barrel

[jareyes]

Originally Posted by Nova316

there is but the little piece of rubber (nub) needs to be parallel to the front not perpendicularity even tho that way it fits easier

http://www.airsoftparts.ca/store2/im...rubber-set.jpg

The nub is that little piece of hopup rubber

What is does is when you turn the wheel it pushes down the hopup rubber into the barrel

So what you're saying is that the "nub" needs to be LENGTHWISE parallel to the barrel? Um.. not to make it sound confusing but I want to be specific: The nub will then on its longest dimension be parallel to the barrel? Because if that's the case I totally have my hopup installed the wrong way (i.e. the other way). I figured it was the way I put it because on the piece that actually pushes the nub, there's a little notch that looked like it fit the nub perfectly. ack! Please clarify if the opposite way of the way I have the nub installed is the way it should be installed. =S!!

[m102404]

There's the barrel..the rubber sleeve...the nub...and the hopup unit itself.

The sleeve goes over the barrel end...there should be a notch in the barrel that runs longitudinally. There's a ridge in the hopup rubber sleeve that matches up with that. Even then...you need to insure that the rubber is aligned right...not pushed on too far, but seated fully...not floppy loose on the barrel, but not tweaked out of shape stretched.

The ridge/notch is the bottom (6 oclock) of the barrel. At 12 oclock there is a rubber bump inside the sleeve that matches up with the cutout notch on the inner barrel. That bump should be centered over the notch.

The nub lays on the outside of the sleeve, right above the bump. It is oriented perpendicular to the long axis of the barrel (i.e. across it).

The hopup unit holds this all in place...and the hopup arm pushed down on the nub, applying pressure to the bump and presses it down into the inner barrel cutout. This "blocks" the bb and forces backspin on it as it passes under air pressure.

If you're rubber is twisted on the barrel...the bump will be pressed in off center (and the bb picks up a combo of back and side spin in relation to the rifle). The nub can be misshapen, too small or off center...causing the same thing. The rubber, barrel and nub can be all alinged with each other...but held a bit rotated off one way or another by the hopup unit.

If it's a "as soon as it leaves the muzzle it goes way right/left" instead of a "it shoots out and gradually hooks right/left"...then the bbs leaving the inner barrel may be hittin the flash hider. It's pretty easy to spot that though. (fragments of bbs in the outer barrel and flash hider are dead give aways).