American Air Arms my 30 caliber EVOL have to try this Plenum

[jwrabbit123]

OK so pulled my EVOL ,30 out and degassed and removed air tubs and installed a large power plenum and since I was there I replaced reg orings , OK so My Evol I tunes to shoot the JSB 44 grains at like 870s here is a small shot string
872,FPS,266,M/S,
875,FPS,267,M/S,
877,FPS,267,M/S,
881,FPS,269,M/S,
879,FPS,268,M/S,
875,FPS,267,M/S,
872,FPS,266,M/S,
877,FPS,267,M/S,
ok I installed power plenum and shot a short string did not touch hammer spring or reg

946,FPS,289,M/S,
942,FPS,287,M/S,
937,FPS,286,M/S,
939,FPS,286,M/S,
938,FPS,285,M/S,
942,FPS,287,M/S,
942,FPS,287,M/S,
IMPRESSIVE INCREASE in next few days will tune for hi power slugs and shoot groups will post here
so went from 78fpe to 89fpe

stay tuned for groups


949,FPS,289,M/S,

 

[jwrabbit123]

OK SO GOT OUT TODAY RAINY BUT LITTLE WIND , I PUT OUT TARGET AT 100 YARDS AND TRIED 47.5 GRAIN SLUGS , 50 GR PELLETS , 6.15 GRAIN SLUGS 66 GR S;UGS . I THREW ON A 3X15 SWFA SCOPE MIL WITH A SET OF NITEFORCE LIGHTWEIGHT RINGS , AND SHOT SOME GROUPS ALL SHOWN ARE 5 AND 10 SHOT GROUPS , TO MY AMAZEMENT EVERY GROUP BUT 1 WAS SUB MOA AND TIGHTEST GROUP WAS 1 HOLE TO BE HONEST IT WAS NOT MUCH LARGER THEN THE SLUG THIS IS FANTASTIC FOR THIS GUN ONLY OTHER THING I DID WAS WHEN BARREL WAS REMOVED I DID DELEAD IT AND GAVE IT A GOOD CLEANING .I CAN ALSO SAY OTHER THEN SIGHTING IN WICH WAS ON MEDAL TARGETS THE FIRST GROUP WAS THE LARGEST I BET IF I RESHOT IT SINCE NOW IT IS LIKE SEASONED AFTER CLEANING IT WOULD ALSO BE SUB MOA , NOW I CAN SAY PRIOR TO INSTALLING PLENUM AND CLEANING BARREL THE 50 GRAINERS WERE SPIRALING , NOW THEY SHOOTING STRAIGHT AS AN ARROW

HERE IS GROUPS AND HOW GUN WAS SET UP

View attachment 20240306_134811.jpg

View attachment 20240306_134821.jpg

View attachment 20240306_140426.jpg

 

[woogie_man]

I have one the first ones from Tom and they are great. Really made the rifle feel much smoother and shot great as well

 

[jwrabbit123]

Yea better accuracy here but to be honest I think deleading barrel made huge difference in mine but the extra 75fps also made great improvement with heavier slugs. also did not seem to affect shot count for some reason , I did all groups with same fill

 

[PumaCarl]

Well, I've got questions, if you would be kind enough to answer them? What was your regulator setting? How big of plenum extension were you using, 12, 27, or the 42cc? I tried the 27cc and it just didn't do anything for me, that I could use. Yes, I could get about 25fps more but it was too loud and didn't shoot as well, so I had to turn down the speed, to where I was shooting w/o using the plenum at all. I had my regulator at around 2400psi and zero mods to my gun, stock hammer and spring, no porting. I have a regular Paradigm .30, not a HPS model. Tom said the plenums were designed with the HPS models valves, porting, and hammer changes and I believe him. I did not try turning my reg back to 2000psi, but I was waiting to hear some numbers.
Edit: I could get 89fpe with the Hades, but they shot better at 87, I could get an accurate 87fpe w/o the plenum extension to begin with, by just putting the reg up to 2400psi. So the extra couple fpe, depending on ammo, I could achieve with the plenum was basically unusable. The 56gr Zan can shoot at 97fpe with the plenum and reg at 2400psi, miserably. Again with no plenum I can get an accurate 87 to 90fpe with just the reg, about 845fps. When I shot past my reg setting, I didn't see my numbers climbing up, so I didn't bother trying turning my reg setting down.

 

[jwrabbit123]

Well, I've got questions, if you would be kind enough to answer them? What was your regulator setting? How big of plenum extension were you using, 12, 27, or the 42cc? I tried the 27cc and it just didn't do anything for me, that I could use. Yes, I could get about 25fps more but it was too loud and didn't shoot as well, so I had to turn down the speed, to where I was shooting w/o using the plenum at all. I had my regulator at around 2400psi and zero mods to my gun, stock hammer and spring, no porting. I have a regular Paradigm .30, not a HPS model. Tom said the plenums were designed with the HPS models valves, porting, and hammer changes and I believe him. I did not try turning my reg back to 2000psi, but I was waiting to hear some numbers.
Edit: I could get 89fpe with the Hades, but they shot better at 87, I could get an accurate 87fpe w/o the plenum extension to begin with, by just putting the reg up to 2400psi. So the extra couple fpe, depending on ammo, I could achieve with the plenum was basically unusable. The 56gr Zan can shoot at 97fpe with the plenum and reg at 2400psi, miserably. Again with no plenum I can get an accurate 87 to 90fpe with just the reg, about 845fps. When I shot past my reg setting, I didn't see my numbers climbing up, so I didn't bother trying turning my reg setting down.

 

[jwrabbit123]

Hi I puma my reg at 2400 and stock hammer spring , my gun is stock other then polishing up barrel and I did recrown it , I did messege you in pm to go over things with your gun

 

[PumaCarl]

I pm'd you back, kind of lengthy for here. My factory settings with 44gr was about 870fps like you. When I turned my reg up to 2400psi, their speed jumped to the 940's just like yours, and this is with no plenum extension. Using the plenum extention with same 2400psi reg and increasing power through my HS setting made my gun inaccurate and loud. No advantage to using plenum extender for me. Other's results may be different, but that's mine. I am hoping more people post their results, before and after. It could be that there is a projectile out there that would have shot well, but I wasn't using it. I tried JSB Hades, JSB 50.1, Zan 56gr, FX Hybrids, NSA slugs from 49 to 54gr.

 

[Airgun-hobbyist]

I put two different plenums in two different Evol's and had similar positive results. Though there were some slight changes when reinstalling, I tried keeping things the same as before for testing purposes.

The first plenum was the 42cc put into a heavily modified .30 caliber with an 18" barrel. It produced another 5-10 PFE depending on the projectile, without changing anything. That Evol runs pellets or slugs between 90-100 PFE, without changing spring tension.

I also put a 27cc plenum extension in a stock .30 caliber with the shorter 15" barrel. In this gun I did rebuild the regulator and cleaned the hammer spring area of lube, so when reinstalling and after settling in the regulator gained about 100+ psi. That plenum also resulted in a decent percentage of power/speed increase, and probably combined from both the increased pressure and plenum extension. It runs between 75-80 PFE without changing the spring pressure.

 

[PumaCarl]

Tom had said that he had a conversation with Lloyd Sikes about the "magic" plenum size a couple of years ago and that it is difficult to pin down but if you find it efficiency can jump up. The 27cc in my Paradigm didn't work out for me, but in for a penny - in for a pound, I just ordered a 12cc plenum extension. Maybe something will come of it. I wasn't really looking to be efficient, but that can't hurt either.