How to grind down .750 on/off pin?/Serious shootdown with emag onoff in classic valve

[halB]

Well, I put the on off pin and an x-valve on/off assembly into my classic valve. yes, it did make the trigger pull much lighter.

Unfortunately, it resulted in serious shoot down. Can't figure that out.

Anyways, I figure I can either figure that out, or grind the pin down to .712 for my emag valve. What is the best way to grind that down so that there are no burs, or what is causing that shootdown?

[Justus]

Can you describe what you observed that you're calling shootdown?

As far as grinding the pin, if you do have the gray grinding wheel (usually comes standard) with a Dremel tool, use that with a pair of needle-nose pliers to hold the pin. It will likely get hot. Just grind flat, and when you are getting close to your desired length put the pin at an angle to smoothe out the sharp edges a tiny bit. The gray wheel isn't very coarse, so I didn't get any burrs when doing it that way.

[halB]

While shooting the trigger pull became noticeably lighter while the sound coming from the barrel became noticeably quieter.

[Cokrkilr]

I think you may have an issue with air getting to the valve. Not the valve its self. When I first set up my pneumag I had a classic valve and I could rip it with and rtp/emag on off. And it had a .750 pin length (that's factory length in the classic)

Also, have you shot.this over a chrono? Or are you assuming its shooting down just by sound alone?

[BigEvil]

I have never made mine shorter than .740 on similar set ups. Trigger pull is noticeably lighter and the velocity is good.

[halB]

Don't know what changed, but now it's just chuffing if I fire it faster than 1 bps. I am using a classic valve with level X that is tuned, at least for the regular on off.

[Cokrkilr]

Check the trigger rod length, make sure a credit card width gap is behind the trigger.

Id try one size larger carrier with no shims on the lvl 10 as well.

Mine had similar issues, the carrier change fixed it. Remember to use the same carrier o ring

[athomas]

Don't know what changed, but now it's just chuffing if I fire it faster than 1 bps. I am using a classic valve with level X that is tuned, at least for the regular on off.

If the level 10 is properly tuned for one on-off it should work for the other unless you are getting a leak in your on-off. You can check the on-off orings by holding in your trigger. If the pressure continues to increase to the point where it pushes the bolt forward and can vent air, then the on-off is leaking. If it doesn't leak or just weeps a bit and then stops, then the on-off is fine. It sounds like it might be choked for air as mentioned.

Is it resetting immediately following a shot (ie; is the bolt reset and the trigger coming fully forward)? If the trigger rod is touching the trigger even in the forward position, then it could interfere with the recharge of the valve.

Is the bolt spring new?

[halB]

Bolt spring is about 5 years old. I tried different springs from the kit. Same problems. Changed the carrier, same problems. Chornoed it, same problems.

I think at this point I'm jsut going to grind it down so I can use it in my emag.

[halB]

I've tried it in two other classic valves, both with level 7. Same thing. Putting the on off seems to drastically lower the FPS, turn it up, still get the chuffing.

[athomas]

Put two level 10 shims in between the two on-off halves. It will simulate a shorter pin and give you an idea if that is the problem.

[halB]

BINGO. Yes, now I can rapid fire. However, I am hearing shootdown. Not as bad as when this all started, but still shoot down.

[athomas]

That is an indication that you are headed in the right direction. For whatever reason, your setup needs a shorter pin.

[halB]

But the pin IS an x-valve or rt pin. I calipered it at .75 (calipers only go to .01", which is why I'm scared to grind it down, however, if the problem doesn't get resolved by tomorrow morning, I'm grinding).

I thought putting a .75 pin with an x valve assembly into a classic valve was rather straight forward.

[blackdeath1k]

Use a file. And file till it is 0.74. And by 0.74 I mean. Till it just no longer shows 0.75. My classic minimag would not cycle at all till it hit .075. And I started with it at .769.