Maccari/ARH full power kit - really full power?

[xxer]

I am about to order the ARH full power tune kit for my HW50s.  I'm going to use a factory Weihrauch seal with it.  My two goals are 1) to smooth out the shot cycle, and 2) to keep the FPE right around what it is from the factory.  To those who have installed this kit: does "full power" really mean you won't lose velocity?  What were your actual chrony results compared with those of the factory spring?

[Denby95]

I have 2, HW50s both with ARH full power kits. Both produce ~11.5 FPE.

I've bought probably around 10 ARH kits for different diana, HW, and webley guns I own. They have always done a great job at taming down any spring twang but they are generally always lower on power, though usually only slightly. The biggest disappointment on a ARH kit I've had was my 21 FPE Diana 460 getting a 'full power' kit that knocked it down to 17 FPE.

Anyways at 11.5 FPE for the HW50, I've been happy with no twang.

[Deerstalker]

The power in my HW95L .22 increased approximately 75 FPS with the ARH full power kit with a Vortek seal.  I installed the ARH kit because of accuracy problems which were caused by damage to the seal due to dieseling so this may NOT help with what you are looking for.  My rifle has averaged 17 FPE for 7K to 9K shots since the kit was installed.  I did not check the FPS when my rifle was new which was a mistake.

If my rifle requires another rebuild it will definitely be an ARH kit.

[xxer]

Anyways at 11.5 FPE for the HW50, I've been happy with no twang.

Assuming that factory is 12 fpe, that's like a 17 fps drop with the RWS Superdomes I shoot in .177.  I can live with that.

[Denby95]

Anyways at 11.5 FPE for the HW50, I've been happy with no twang.

Assuming that factory is 12 fpe, that's like a 17 fps drop with the RWS Superdomes I shoot in .177.  I can live with that.

That was exactly my thoughts especially at the benefit of eliminating twang and a smooth shot cycle.

[EMrider]

Same experience here, ARH kit and Vortek seal gave me about 11.5fpe-11.7fpe in my hw50s (.177).  Good shot cycle, but I eventually went to the ARH indoor plinker kit and like that best.  Good luck.
R

[Mark 611]

Piston seals make a big difference, their fit must be correct, if it's tight you will lose power to lose it will slam at the end of the stroke, my 50 in .22cal runs at 11.9ftlbs with 14.66gn FTT's, The Hornet kit for the 50 is a good kit, I have 3 HW50's running this kit, this kit is also good in a 95 size tube if you want to reduce velocity and make it more of 50 power range rifle, 

[Yogi]

I am about to order the ARH full power tune kit for my HW50s.  I'm going to use a factory Weihrauch seal with it.  My two goals are 1) to smooth out the shot cycle, and 2) to keep the FPE right around what it is from the factory.  To those who have installed this kit: does "full power" really mean you won't lose velocity?  What were your actual chrony results compared with those of the factory spring?

Please remember that power diminishes with altitude....
Thinner air pushes the piston slower.

-Y

[Robert 5mm]

Concerning altitude and pressure - a springer reduces FPS at 29 FPS per 1000 feet above sea level.
Less air molecules to compress from the same initial volume in front of piston.

Here are two quotes from two other members from another Forum - Motorhead and Bob Sterne

In a FIXED volume that is a spring guns firing mechanics ... AIR DENSITY differences will change pressure produced during the firing cycle.
Warm thinner air or higher altitude act the same pretty much reducing power potential where as Cool dense air or low altitude has the highest energy potential.
There is that somewhat grey area thats hard to validate where due to lower resistance of thinner less dense air speed of driven piston creates a slightly faster spike in pressure during the shot and the losses one would calculate become less so


The ambient pressure indeed reduces the peak pressure and the velocity of a Springer, and in fact a Pumper as well (at any given number of pumps).... It does not affect a PCP filled to any given GAUGE pressure, (or CO2, which is temperature dependant) because that is compensated for by the gauge (it is psi above ambient).... Once fired, regardless of the gun firing it, the pellet will meet with less air resistance at higher altitude, and carry a larger percentage of it's velocity and energy to the target.... but starting from a lower velocity in the case of a Springer or Pumper....