Mag Tune-Up: Erratic Velocity

[MikeRosenthal]

Hopefully you guys can help me troubleshoot my valve.

(Background, skip if your impatient: I used to play a lot of pball back in the day(89-93) But didn't really play through college and just got back into it recently. I played with an F1-Illustrator at that time. A few years ago my brother gave me his old Classic Valved mag when he went to an autococker. Besides a few test shots in the back yard i never used the Mag untill Last Month.)

I've got a handme down Classic Valved mag that i used for the second time yesterday. While it preformed well i did noticed some issues that i'd like to try to fix. The most pressing issue was erratic velocity. Even when not shooting all that fast the velocity would sometimes swing quite wildly (220-290fps). So i had to set it rather low in order to not be shooting hot.

Secondly, I was experienceing severe shootdown (Or maybe i was shortstroking it.. i'm not sure) when i tried to shoot fast, usually my 6th or 7th ball of a quick burst whould sort of just plop out of the barrel... maybe at 150 fps.

Finally, at the end of the day during our only speedball game i was getting a double feed every once in a while. I assume this means my indent(The metal paperclip thingy in the barrel) isn't in far enough? Before i started bending it i wanted to make sure that was the only thing that would cause it.

Tech Details:

My Bolt Spring seems like maybe it's too weak. When out of the gun it just barely is larger than the bolt. From pictures of newer springs it looks like they clear the bolt by a much larger margin.. Could this be the source of some of my problems?

The first time I played with the gun(about a month ago) I didn't realize how bad liquid C02 and the mag mixed. As a result it vented a few times that day. (this scared the crap out of me till i read up about the automag here on AO) Could i have ruined some o-rings that day and that is leading to my valve inconsistancy? Yesterday i used an Expansion chamber and a much longer Stainless Steel Hose. I didn't have any of the liquid CO2 problems yesterday that i did the first time.

Saturday Night After redoing all the Air lines i submurged the gun(AIR'ed up) to verify it wasn't leaking. The Valve seems fine in that regard.


OK, Thanks SO MUCH if you made it this far. What do you think?

THanks,
Mike

[Dayspring]

Lube the on/off assembly, replace the reg-seat oring.

[MikeRosenthal]

Lube the on/off assembly, replace the reg-seat oring.

I bought some PBgun Oil when i ordered up the expansion chamber. Or do you mean some other type of Lube? I Lubed the gun Through the ASA and through the two holes marked "Oil" on the valve.

To do the On/Off I should pop it out of the valve and just apply a few drops?

"replace the reg-Seat oring" Do you mean the "Regulator Piston O-Ring" or the "Regulator Seat"

I used this for the part names... http://www.airgun.com/downloads/valveexplodedview.pdf

Thanks For the Quick Response.

OT: Btw, I used to live in Chatham.....

[Potatoboy]

He means the reg seat.

Putting a few drops on the on/off assembly itself won't hurt, but I don't think that's your problem.

Putting oil in the ASA should have been sufficient, and you do not have to put any oil in the holes marked oil.

The bolt spring should be longer than the bolt, and it sounds like yours may need replacing, but it is possible that the bolts you are seeing with super long springs are level 10 bolts which use a greatly longer spring than your stock bolt.

The spring you need to be using has a yellowish gold color to it.

You can find a new bolt spring and two reg seats in the AM/MM Parts kit, along with some extra spare orings.

[MikeRosenthal]

Thanks for the help. On the way home from work i picked up 2 regulator seats. It took 2 stops, not bad i guess. Although the 15 year old punk at the first place told me i was shooting a dinosaur. I wonder what he would have said if i showed him my F1

Of course now i realized i don't have any way to test the marker and see if the reg seat solves the problem. hmm i need a freakin chrono


Regarding the Double Feeding. I have a couple of the newer plastic ball detents.. are they better than the old metal type?

[toymyster]

Dinosaur, hmmm!!! Think he's ever seen a Nightmare, or a Splatmaster??? Yes, the plastic nubbins are much better, specially since they just don't wear out!!!!

[MikeRosenthal]

I've replaced the regulator seat (Poped it into the back of the regulator)

But now the valve doesn't seem to want to close all the way.

The Valve closed fine without the reg seat but now i'm about a quarter of turn away and it feels like i'd break something if i forced it.

I'm not sure what to do now.. I've double checked half a dozen times..

Edit: Finally got it on. The new reg seat seems much larger than the old one. Only one of the two new ones would stay in the reg seat properly. The other one just seems too small

[pbg1]

nelson 007 ....lol that what we started with

[JimmyBeam]

maybe i missed it if you said you were or not, but sounds like your using CO2. go compressed air and n o more worries. mine did the exact same thing when i had CO2.

[Carbon Blue]

I've replaced the regulator seat (Poped it into the back of the regulator)

But now the valve doesn't seem to want to close all the way.

The Valve closed fine without the reg seat but now i'm about a quarter of turn away and it feels like i'd break something if i forced it.

I'm not sure what to do now.. I've double checked half a dozen times..

Edit: Finally got it on. The new reg seat seems much larger than the old one. Only one of the two new ones would stay in the reg seat properly. The other one just seems too small

your supposed to snap the bigger side of the regulator seat into the back half of the regulator. It will actually make a clicking noise. Make sure u oil that part too!

[rb211]

As stated above, switching to compressed air will solve part of the erratic velocity, ambient temperature greatly affects CO2, meaning that the colder it is, the less pressure you will get from your tank resulting in lower velocity. Compressed air stays consistent regardless of temp.

[Boydster]

Yah, reg seat should fix your velocity problem. About that shoot down. Can you describe what the on/off looks like. If you have a Z-Valve, that's exactly where the shoot down is coming from. Mine does exactly what you described. When I replaced it with a normal stock on/off, it worked great. Try describing it to us.

When I replaced my reg seat, it was also really hard to screw the two haves together. I guess that's because it's new, IDK.

Don't take your reg seat out often. Whenever you screw the two halves together the valve part makes an indention on the reg seat. Unscrewing it and then screwing it back together will make another indention in a slightly different spot. This causes erratic velocity and velocity problems. When you go to replace it, just leave it there forever until it needs replacing or oiling. You should probably oil it every 5,000 shots. (That's a lot for a Classic mag lol) What would you even need to do in there? You have a spring and a pin and that reg seat so don't open it just to have a look.

Definitely always use the plastic ball detents. (They're actually called nubbins) You don't need to adjust them because, well, you can't adjust them. Plus they last a lot longer.