Fx dream plenum

[Etienne]

So i finally got hold of a fx dreamline lite bottle in .22, thing is, while i was shopping around trying to find a store that had this rifle in stock i found a store that had a dreamline plenum in stock so i bought the plenum before i had even ordered the rifle. So to my surprise when i finally got the rifle and opened the box it already had a factory-installed plenum, i called the store and they informed me that the last shipment of dreamline rifles they received from fx already had plenums installed,thats awesome. HOWEVER, the plenum i bought separately before i bought the rifle is bigger than the plenum fx supplied with the rifle, there's no indication of the size of the plenum on the rifle and same story with the one i bought, so what i want to know is, how many different sizes of dreamline plenums are there and does anyone know what size the plenums are that fx is supplying with the dreamline rifles, thanks, Etienne

 

[TMH]

Etienne,

Can you show us a photo of your new gun, specifically showing the area with the factory installed plenum? I have not seen various size Dreamline power plenums, but FX is known to make rolling revisions of their guns while in production.

I have seen what appears to be factory installed plenums on only some of the Dreamline Compact bottle guns, but not before on a regular Dreamline Lite.

Know also that you can generally also fit your pre-purchased plenum onto your new gun to get an even larger plenum volume. I recently installed a stack of 2 power plenums onto a Dream-Pup I had purchased. It is a .25 cal, not like your .22, but without touching the regulator my maximum pellet velocity went from (stock, no power plenum) 910 fps to 945 fps (2 power plenums installed) using FX 25.4gr pellets. 

I was then able to reduce the regulator pressure by about 30 bar, and obtain the 880-890 fps I wanted just using the power wheel and hammer spring dial - and get a bunch more shots per fill. With the 2 power plenums in place I can quickly and easily obtain pellet velocities between ~820-920 fps (could also go lower but I did not chrono test at any hammer spring settings below #3).

You won't need to try to optimize your shot count quite as much as you have a big bottle as compared to the smaller air cylinder on my 'Pup, but these guns with the power plenums installed sure do give you the quick and easy ability to optimize your muzzle velocities for different pellets or different shooting situations. And being able to run the regulator at a lower pressure, in my opinion, may lead to a longer service life of this component.

 

[brillerino]

I got my dreamline in june with plenum installed (i did the same mistake as you) on first sight it looked bigger but 50% ish of the size was threads on mine and i realised both where the same size. Pictures would help

 

[AlaskaAirgunner]

That is good to know that the new ones are shipping with the plenum. I am in the market for a dreamtac compact in the near future. If it were me, since you already have the plenum, I would experiment with each of them and with both stacked. There has been lots of posts in all the groups about two plenums on the dreamline series rifles. And all of them had positive results that I have seen...

 

[Etienne]

Ok,theres a few pics of the factory-installed plenum and the one i bought, the factory one measures around 28mm and the bottom one around 39mm ,plus minus 10-11mm difference which is about 25% . Currently the rifle is pushing 25.39 jsb monters 865fps on high power and almost maxed out hammer, with the regulator on what looks like about 135bar, so im happy with the velocity, 18.13 jsb on max power going 970fps and 15.89hades over 1020fps, but i turn the power down when shooting the lighter pellets, above velocities is just an indication of max power with the small plenum at 135bar, so if i install the bigger plenum hopefully i can reduce the regulator pressure and still keep the velocities up

Et

 

[TMH]

Well, it appears to me that the Power Plenum you have factory-installed on the gun is the standard Dreamline PP. The longer one, I don't know.

The photo below shows my DreamPup with the stacked 2x standard Dreamline PP's. 27mm and change in length.

And to answer your last question in the post above - Probably. One will eventually get to the point where additional plenum space does not continue to give the ability to lower reg pressure but maintain muzzle velocities.

Sounds like you have a chronograph and have clocked the gun in the current configuration. I would try stacking in your 39mm PP and re-chrono testing, and also installing the 39mm PP alone and see how much difference each revision makes at the same reg pressure. That should give you an idea of which PP or the combo is the best fit, and then play with reg pressures, power wheels and hammer spring settings.

 

[Etienne]

I was planning to do do exactly as you suggested, install the bigger one and compare the performance to the current settings and then stack the 2 plenums and compare again, if i can get the 25.39 jsb monsters up to 900fps plus with the standard barrel i would be very happy. I'm awaiting delivery on a tube of silicone grease for the plenum o-rings, once I've tested the different setups i will post it here,thanks for the feedback, i appreciate it.

Etienne