milsimcombat.com

I have a new AT-4 Tactical that has been working great since I got it. Very suddenly one day during practice it stalled. Upon releasing the mag, a paintball was jammed in the receiver and a pin was bent in the mag. Ever since then, no matter what I do, I can't get the marker to fire more than a few shots without this happening. I straighten all the mag pins, index it properly, and I can fire it all day with an empty mag. The second I add paint, I get a few shots then a jam and bent pins. It also appears the bolt may not be coming forward all the way when I hit the reset. Any ideas? Why would it work fine without paint, but mess up so bad with paint?

Thanks,
Bear

Better spaeking to loudthunder on this forum.Or maybe one of the other lads with AT's may be able to help you

Have you tried removing your guide plate repressuring the marker then put the guide plate back on? I had something similar but stripped down the AT put it back together again and the problem went away not sure what I did though?

Milo any ideas?

Hmm,

Sounds like you need to remove the regulator, be careful! lots of little bits inside and more importantly, ensure that you scribe on the regulator allen key head its 12 o'clock position, (pointing towards the handgrip). Then when all the reg is out, connect the air line and blow any crap out of the AT. Once that's done put four or five drops of ATS oil into the reg hole and refit the reg. If the AT is old then the regulator spring should be replaced. If you have a reg kit replace the whole reg. Next thing, wind the bolt counter clockwise till it stops, then wind it back in 7 time clockwise. This should put it about factory setting. Gas up the ATS, checking it's indexing correctly as you fire.

What happens is the ATS goes out of time if the air flow through the marker is incorrect. It will seem that everything is fine when it's dry fired, but what in fact is happening is that the mag is mis indexed, and so will cause ball chops.

The bolt and the regulator need to be in harmony for the ATS to work properly. A bit of adjustment now and again is all that's needed to ensure it works.

Try all that and let me know how you get on. I reckon that that will do it for you. Check the guide plate for damage while you are at it, you never know.

I've tried pressurizing with the guide plate off.

I think I've tried everything in the manual actually. Thants why I'm here. The marker was working perfect, and it was a very sudden occurence that this started. Not like it was getting gummed up and performance slowly declined until it quit. It was it top form one shot, dead the next. When the trigger stalled, I dropped the mag and there was a ball stuck in the receiver along with a bent pin in the mag. I shrugged, cleaned everything out, bent the pin back, and tried again. Same thing happened again. Sometimes I get 4 shots, sometimes 2, sometimes none.

On an empty mag I can shoot it till I'm out of air no problem, but only when I put paint in it does this happen. It's always a ball jammed in the reciever and pins bent in the mag. I've torn the thing down almost completely and cleaned it, lubed it, and put it back together according to the manual. The only thing I haven't messed with yet is the markers regulator. I was about to call up northerncommandpaintball.com where I got it when I found this forum and saw that loudthunder was here. I wanted to join this forum anyway so I figured it was a good way to start.

At first I thought something was bending the pins, and then causing the mag to jam and the marker to stall. Now I think the problem is in the marker and causing the pins to bend. I also am now thinking the bolt is not coming all the way forward, which might be why it's stalling in mid-cycle, jamming the ball halfway into the chamber, and bending the mag pins all up. I've only had the thing a week, so I'm still figuring all this stuff out. Thanks for the replies so far, I hope I get this figured out soon.

Well, off I go to clean it all out. Again. I'm just about out of ideas.

Bear


[EDIT] I was writing this and hit post just as Milo posted. I'll try removing the reg and doing the adjustments you suggested, but this is a brand new marker. Less than 200 rounds thru it so far...and over a dozen have been chopps.

Ok, I haven't had time to try the regulator yet, but I've got a new development. I tore down the marker, cleaned and lubed everything, put it all back together, and made sure it all went back together right. I've got the bolt closing all the way now, but I'm still jamming up with paint. I see that the magazine is NOT indexing properly. I index the mag so there is a pin in the little viewport, but when I dry fire the marker the pins don't line up with that little window. Maybe 1 in five or ten shots will line up properly, but most don't. Also, with paint in the marker, I hear the initial shot, but the second half on the cycle sometimes doesn't happen. Once in a while it will be delayed a second or two. Almost like something is sticking. So, with these two issues, does anyone have a better idea on what might be wrong? I'll be trying the regulator idea from Milo tomorrow if I don't hear anything else from anyone. Thanks again for the replies.

Bear

I have to agree with Milo Bryan. Try what I emailed you. It seems to me like the bolt seal is also missing *the more I think about it*, or its an air issue. If your still having issues, give me a call and we'll see if its something else. Believe it or not this has happened to me as well. Took me and Gumby a year to figure it out. This sounds exactly like what was happening with mine (loooooong time ago) this is how I found out about my tank over pressuring the marker and causing all kinds of havoc with me and ATS.

Got your email, I'll play with the marker today and see what I can come up with. Thanks everyone, hope it doesn't take me a year.

Bear

Bear, if you do as i have said i'm confident that it will solve your problem. Check you have a bolt seal as LT has mentioned otherwise it will cause you problems. Also make sure that the barrel is the last thing to go in, it can affect the markers ability to work on semi if you put it in first.

I have had the same issue before with my AT4, i resolved it in the way i have said in my previous post. The velocity, regulator, bolt spring and seal are all linked, they all need to be right for optimum performance. As the markers age so do the critical parts, this can cause the marker to go out of tune as it were.

good luck, let us know how you get on.

I've finally (I hope) figured it out. After spending some time looking at the parts diagrams in the manual, I was able to notice that I am missing the front coupling spring washer and retainer. Don't ask how I managed to lose them, because I have no idea how I did it, but I did. I'm really confused on that one, because I've never attempted to dis-assemble the piston at all.

Without the washer and retainer the forward coupling spring can travel to far forward, even up the 90 degree bend, which lets the coupling assembly travel to much and preventing it from moving the cog thru a full cycle, thus mis-indexing the mag every shot.

To replace them it looks as though the entire piston assembly, including the timing collar, will have to be dis-assembled, which I am definitely not qualified to play with. So I've talked with loudthunder and he is helping me out with getting it repaired, so hopefully my marker will be operational again shortly. Thanks for everyone trying to help me out!

Bear

Just a quick note to let you know that my AT4 is back in action. I got a 1/8in retainer from the hardware store and popped it in, and the mag is indexing properly now. I've put over a hopper thru it so far with zero issues. Thanks for all of the help guys, I hope it's smooth sailing from now on.

Bear

I really, really, really wanna get to rocking my splatmaster. Picked up a case of marbs for it, and turns out, the bore is too big for the barrel They just get stuck halfway down it. I tried allstars, same diff. I dont really know of anything smaller bore, do you guys?