Minimag Won't Fire More Than 3 Shots and then Hisses

[davidthesteak]

I have an older minimag with level 7 that has worked fine as recently as last fall. Here in Utah we don't get to do a lot of paintballing during the winter, so now that it's warming up, I took it out and now the problems have started. It will gas up just fine, but unless the velocity adjuster is screwed in all the way, it won't fire. If it's screwed in all the way, I can pull off about three shots and then the gun just hisses down the barrel with all the air coming out down the barrel. If I hold down the trigger, it stops hissing, but if I let off, it hisses again. If I turn off the air and then retry things, it will do the same thing, 3-4 shots and then hissing unless the trigger is held down.

Before I get a bunch of helpful comments about the little things, here's a list of things I've tried:

replaced every o-ring in the gun
replaced the spring
made sure everything is oiled
played with unscrewing the body screw a little bit and the field strip screw a little bit
replaced the bumper
cleaned every part I could
replaced the on/off assembley
tried CO2 and HPA (with full tanks)
called AGD and they said all they could think of was to send it in or take it to a professional (but seeing as how I'd rather spend my money on paint than a professional...)

Any help would be greatly appreciated as I have no more ideas on what to do. I have an automag classic that I have put the valve in with the same problems and vice versa I have put the automag classic valve in the minimag body and it works just fine. I'm out of ideas, so I hope someone out there can enlighten me.

[rb211]

If you are having to screw the velocity adjuster all the way in, that sounds like a reg piston problem. Are you using the stock velocity adjuster or an aftermarket one? Check your sear for wear and your bolt. Do you have a spring or a solid spacer in the power tube? If it is a spring, get a spacer kit from AGD and retune. Oil the heck out of it and try again. We'll be here.......

[davidthesteak]

My velocity adjuster is stock. As of last fall I never had to screw it in more than half way to get it right at 280 fps. I do have a spring in the power tube, so I guess I'll be getting the spacer kit and trying the different sizes. Do you have any idea if I need a bigger or a smaller size?

[rb211]

Hard to say, the most common one I've seen come stock in a mag is the .220 spacer. I'd start with that one. Here's a link to AGD's site and how to tune them.

http://store.airgun.com/index.cfm?fuseaction=catalog.prodInfo&productID=413&categoryID=18

Hope this get's it.......

[shades]

It sounds like a reg problem.
You are getting less a less pressure behind the bolt until it can no longer reset itself.
Check your reg assembly for dirt/rust or general crud.
Clean the spring pack with a ton of wd40.
Make sure your reg piston is smooth and you have a new oring on it.
Check your valve pin and spring for smoothness and if possible replace your reg
seat.
Put a drop of 3 in 1 oil on your now cleaned and dried spring pack and one drop of 3-1 on the reg piston.
Check the reg body for debris and/or marks and relative smoothness.
Screw out your adjuster and reassemble.
Put three drops of 3 in 1 in your ASA. reassemble the marker and dry fire the marker(100x or so) without the barrel. Hope this helps or send it to me (the valve and bolt) and I try to fix it $4 us postal. if i cant ill send it back no charge. If i can you owe me postage. :D