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View Full Version : MM fps on 400+ not lowering



Chencho
05-26-2013, 08:33 PM
so, my minimag... took it to the field to chrono it, and it dont want to go under 400+ FPS.

Is it the regulator seat? you can see the shape of the valve and pin on it. Im ordering a O-ring replacement.

is there anything im missing?

thanks!

(just shot my first x-valve today... fell in love :ninja: )

Frizzle Fry
05-26-2013, 08:37 PM
Classic valve or X-valve?

Was it leaking?

Chencho
05-26-2013, 08:42 PM
Classic valve or X-valve?

Was it leaking?

Classic MiniMag valve
was leaking down the barrel, changed powertube O-ring and leak fixed.

Chencho
05-27-2013, 08:12 AM
Only the leak was fixed, still not going under 400fps. When I try the valve just doesn't pressurize

BigEvil
05-27-2013, 09:30 AM
That is a pretty serious problem.. I would rebuild the entire regulator portion of the valve. New valve seat, valve pin, and spring pack. Also change the piston oring.

BigEvil
05-27-2013, 09:31 AM
Do you have an aftermarket velocity adjuster on there?

Chencho
05-27-2013, 11:37 AM
Everything stock, even spring in the powwetube.

So, buy the whole oring kit +spring and pin?

BigEvil
05-27-2013, 02:02 PM
Everything stock, even spring in the powwetube.

So, buy the whole oring kit +spring and pin?

I would. Tell Tuna you need everything but the piston.

Chencho
05-27-2013, 02:14 PM
I would. Tell Tuna you need everything but the piston.

Alright, will update when I get it.

If anyone else has more info I should know, plz post.

athomas
05-28-2013, 05:45 AM
Only the leak was fixed, still not going under 400fps. When I try the valve just doesn't pressurizeIf it doesn't pressurize, it is generally an indication of bolt stick. Since your mag is original with the powertube spring, I suspect you need to install a powertube spacer that is longer than the spring you are using now. If you know someone who has a mag with a level 10 bolt, get one or two of his shims and use one at a time to see if they help.

A bad regulator seat oring will cause a high pressure in the front chamber which will result in a high velocity. Usually, the valve will vent air out the back when this happens.

I would change all of the orings as a start anyway so that you know what you are working with. Most mag problems are due to a bad oring.

Chencho
05-28-2013, 06:45 AM
About finding someone with another mag... When i got to the field players were like "wow, where you got that?!" Lol

I know someone with an xvalve, that's about it. Will change all the rings and eventually buy a slavery kit. I'm waiting to come back from the trip I'm going today to drop the money.

Thanks for the reply :-)

splatzone
05-28-2013, 07:17 AM
What's up :)

Chencho
05-28-2013, 07:24 AM
Sup splat, trying to get my lil one fixed to go back in the field!

Spider-TW
05-28-2013, 01:22 PM
If it doesn't pressurize, it is generally an indication of bolt stick.

:confused: What are you guys seeing in "doesn't pressurize"? I don't see how it lacks pressure at 400 fps.

Chencho
05-28-2013, 01:35 PM
When I turn the back screw counter clockwise to lower the fps it just "shuts down" it doesn't cock back.

Spider-TW
05-28-2013, 02:48 PM
When I turn the back screw counter clockwise to lower the fps it just "shuts down" it doesn't cock back.

Perhaps the spring pack is in upside down. The classic valve spring packs have a center post that runs into the pocket of the piston. If you put it in upside down, the adjuster nut just cranks on the post, making it on or off "regulation".

Chencho
05-28-2013, 02:56 PM
I'll do that when I get back home and see, that may be it. Its something like on/off... Mmm...

athomas
05-30-2013, 03:54 PM
:confused: What are you guys seeing in "doesn't pressurize"? I don't see how it lacks pressure at 400 fps.In post number 4 it mentioned "When I try the valve just doesn't pressurize". I assumed that when he tried to fix one problem, he caused another.

Chencho
05-30-2013, 04:05 PM
Nah, the powertube leak was the PT o-ring.

Now is that it doesn't regulate under 400fps and it does something like on/off like spyder wrote

Chencho
05-31-2013, 07:44 PM
Perhaps the spring pack is in upside down. The classic valve spring packs have a center post that runs into the pocket of the piston. If you put it in upside down, the adjuster nut just cranks on the post, making it on or off "regulation".

Just got home, checked the pack and aparently that was it, trigger is light as it was and shoots quiet. Chrono tomorrow and will update. Just learning with every mistake :-)

Chencho
06-02-2013, 04:24 PM
My baby is shooting.like a pro again!!

Thanks to you all, idk what I would've done without AGD addicts :-)

Thank you!!