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Griff1950 · Member

Well, I got my order in from Pyramyd, and got my trigger group reassembled so I could start installing the Air Venturi gas ram. It is NOT just a drop-in installation, as some would have you believe. The spring guide must be modified by having the tubular portion removed. I cut mine down with a cut-off wheel in my Dremel tool. The base of the spring guide must be retained, as it has the holes for the crosspin and a threaded hole for the stock screw. I simply ground it smooth on the face where I cut off the spring guide. The plastic bushing on the back end of the gas ram also had to be cut out to clear the trigger housing. OK, now I've finally got all the parts fitted and pieced back together, so I get out my trusty bar clamp that I used to disassemble the gun. I set everything up and got my big surprise. The light-duty clamp that I used to tear the gun down couldn't even compress the ram enough to install the crosspin. Out to the shed for a heavy pipe clamp and put some oomph!!!! on that ram. With the added muscle, everything went back together without further problems. I had only lightly used moly paste when I reassembled everything, but when I cocked it, I thought it was gonna give me a double hernia!!! It cocked much harder than my RS2, which is a real bear. I had done some work on the trigger and sear while the gun was torn down, so I was very cautious that first time. Everything seemed to be holding together, so I loaded a CPHP, stuck it out the shop door and put one into the ground. Apparently moly paste is combustible, because there was a loud crack when the gun went off, some fire from the muzzle, and a strong smell of smoke. Due to the noise, I decided to put off any more test firing till tomorrow, when my neighbors wll be at work. Will shoot some more over the weekend and post my findings.

broommaster2000 · Moderator

DANG. Surprisingly hard. Neutral

That's what sucks about aftermarket gas springs, you can't let out any air to make the cocking go smoother. Neutral

fritz · Silver Status Member

Aren't the gas springs supposed to be depressurized for installation? Then filled and tuned afterwards?

Griff1950 · Member

fritz, this spring is sealed, no chance to try different pressures without additional machining.

fritz · Silver Status Member

Figured that. IIRC the Theoben springers have an adjustable spring.

Buster Bodine · Veteran Member

Looking forward to hearing more about how this works out for you. I was considering doing the same thing to my BC but the guys here pretty much talked me out of it.

It'll be good to hear the results from a slightly more adventurous spirit. Mr. Green

Griff1950 · Member

I still haven't had time to thoroughly check out the Big Cat with the gas ram yet, but did fire it a few more times today. It's still going supersonic with CPHP's and dieseling a bit. I don't understand where the dieseling is coming from, because the only lube I used was a bit of moly paste on the piston and the back edge of the seal.

I was shooting from inside the shop, and my wife came out on the deck and told me to quit shooting the .22 (rimfire, she thought!). Told me that if she was hearing it, the neighbors could, too.

This is somewhat bothersome, because I can't return the rifle to it's original condition without a new spring guide. I'm beginning to think this is a bad swap.

I was able to reduce the cocking effort by a great amount by a judicious application of grease to some of the friction points in the cocking mechanism. Cocking still requires more effort than the original, but is now seamlessly smooth.

I guess I'm going to have to order some real heavyweight pellets and see how it goes from there. If I can get it subsonic again, I think it will be fine. Recoil is directly in line with the barrel by the feel of it. No twang, no twist, just a straight line recoil with no other disturbance. I think with the right pellet, it might be a real shooter. I've just gotta find the right ammo.

broommaster2000 · Moderator

Good luck, I've always found Baracuda 10.5 grainers to work well in heavy springers. Else, you might wanna look into a .22 barrel?

Buster Bodine · Veteran Member

My BC seems to really like Gamo Rockets and at 10.9gr, it should slow you down to subsonic and give you awesome accuracy as well.

I dunno bout your part of AR but the Walmarts in Hot Springs are selling the 150 pellet packs for 3.96 a can. That's much cheaper than the few places I've looked for them online.

ETA: I wish I had your problems. I can shoot burners in my backyard and nobody minds. I'd love to have a consistently supersonic BC! Mr. Green