insonsistancy of a mimimag

[barjohn]

Hey I got a minimag that is approx 12 years old. everything works fine on it accept for the fact its very inconsistant like 270-274-290-280-301-290.
The regulator seat puck is fine its all oiled up fine all the o-rings are ok I have the original bolt that came with the gun. I am running high pressure Compressed air. The only one thing that I see might be the problem is the regulator piston. it was hard to get a close up picture of my regulator piston but the part that looks like an allen key would fit in is warped and a-little higher on one side the the other. think this could be the problem cuase when it pushes on the spring the spring will not be completely flat and be kindda off.

[Dayspring]

If you've unscrewed the valve halves, you should replace the thick reg seat oring.

Even a little deformation can pinch the reg pin & give you the issues you speak of.

[barjohn]

as i said it is not the regulator seat puck o-ring.

[Paintmanmike]

I had inconsistency problems and worked thorugh everything; replaced all the seal, on-off rebuild, Lvl 10 dial-in, and a new regulator piston and spring pack. Everything in the regulator must be pristine in order for it to do its job right. Once you get it that way screw it together and never open it unless something fails.

However in my case that was not enough and I was left scratching my head with inconsistent velocity on the order of what you are seeing. What finally fixed it was that the main bolt spring broke and when I replaced it with a new one, once the spring broke in, the consistency was back to great. 280 +/-5 fps is nice.

I guess they must work harden as they age and maybe it has something to do with using a cut spring with Lvl 10 and the way it hardens in the last half a turn must interact with the way it engages the bolt face.

[hardr0ck68]

ok to help you out im gonna insist you use the parts actual names

I dont know what a regulator seat puck o-ring is but i do know for darn sure alot of the inconsistancy problems that crom from a standard valve are bad reg seats.


When the air pressure pushes the reg seat into position for the first time it forms a ring on the reg seat, this ring needs to seat in the correct position to get a good seal. Now when you split the reg halves and try to reuse a reg seat it is just about impossiable to make the first ring in the reg seat line up again.

What happens is when the air pressure hits the used reg seat it adds another ring to it, that is slighly off from the last one (were talkin thousandths of an inch here), and air can creep by through the origional ring in the reg seat, causeing inconsistant pressure in the dump chanber....this will give you your 270-274-290-280-301-290.

So, in short NEVER REUSE REG SEATS ON A PERFORMANCE PRODUCT!

[peewee]

Puck O-Ring= reg seat in Canadian!! shot gun shell = reg piston in my neck of the woods. .

[barjohn]

ya ok here is what i did. I went though entire bolt/regulator/valve assembly. oiling all o-rings and replacing the bad ones. took out regulator piston greased up spring pack and regulator piston put them back in put in a new puck ( regulator seat ). gased it up on week end and it was inconsistant as crap. I put in a new spring ( bolt spring ) not but 1 month ago so its still good. so now i take it apart to try and find the problem noticing that the regulator piston assembly is warped slightly on the allenkey side so when the spring pack sits againced it, it may not be sitting completely flat on regulator piston. if ya know what i mean. and scince you push the back in to up the volosity i think that might have some effect on it. what are your thoughts.

[peewee]

i believe that there is also a seal /diaphram in the bottom of the reg piston that can go bad. I had the same kind of issues with an old mag I swapped out the entire back end ( shotgun shell & spring pack). No problems after that.

[Dayspring]

And as I said, if it's been taken apart, the reg seat needs to be replaced.

as i said it is not the regulator seat puck o-ring.