Is my Huma regulator creaping?

[robertr]

 I installed a Huma regulator in the Marauder and after a test over the chrony I noticed if the rifle sat for a while the regged pressure on the gauge would creap up a couple hundred psi and my first shot after sitting for a few minutes is higher than the following shots by around 15 to 20fps. The fps then stabilizes untill I let the rifle sit again, is this from the regulator creaping and how can it be fixed?

[rsterne]

Yes, it sounds like the regulator is creeping slightly.... If you back off on the hammer strike, you may find that you don't lose any/much velocity, and when you are low on the knee of the curve you should find that the higher pressure after sitting would actually lower the velocity slightly.... Somewhere in between, you should be able to find a spot where that 200 psi change of pressure won't make any measureable difference in the velocity, because your gun would be tuned like an unregulated PCP operating right at the peak of the velocity bell-curve....

If when you find that spot, your velocity is lower than you want, then bump the regulator setpoint up slightly, and increase the preload slightly to get back to the (now higher) sweet spot....

HTHs....

Bob

[robertr]

 Thanks Bob, I will back off on the hammer spring a bit and see if it helps.

[robertr]

 I have also hread something about a disc that can be flipped over or changed, does this sound familiar?

[robertr]

 Surprised no one here has any info on the disc , after a Google search apparently that disc can be flipped over or be replaced. Lowering spring tension did not help. So I guess that is what I will be doing next.

[rsterne]

What happened to the velocity when you lowered the hammer spring preload?....

Bob

[robertr]

 Velocity went down.

[rsterne]

Well, at least that tells you that you are NOT on the plateau.... I guess a rebuild is in order, and yes, turning over the disc may work....

Bob

[robertr]

 Thanks for your help Bob, one more question , the regulator is still fairly new with maybe a couple hundred shots through it, could the creaping be because the regulator is not broken in enough yet?

[rsterne]

I doubt it, but I'm not a user of in-tube regs.... It could be the wrong O-rings or the wrong lube, also.... PM Scott (Motorhead)....

Bob

[robertr]

 Thanks Bob.

[robertr]

 I just finished taking the reg apart and flipped the little white disc over for a new sealing surface, filled the rifle up and took a couple test shots, all seems good , the gauge stays the same now and does not creap up in pressure like it did before. I will keep an eye on it but I think the problem is fixed.
 Thanks for your help Bob.