Author Topic: The 9mm Disco Double (Read 26441 times))

rsterne · « **on:** March 26, 2012, 07:54:58 PM »

Lloyd Sikes of Crosman Rogue fame has just released his latest creation, the Disco Double twin-tube conversion kit.... I was fortunate enough to get on his list for a Beta test kit because I had an ideal candidate.... my .308/9mm Disco.... The purpose of the kit is to double the air capacity, so what better than a 120-140 FPE rifle that only gets 4-5 shots per fill.... Although the production kits will be properly finished, the Beta test kits were supplied "in the white" (ie not blued).... The kit consists of a new CrMoly steel lower tube which fits up snug against the bottom of the original air reservoir, plus all the necessary fitting to complete the installation, including a new barrel band.... The new tube sits flush with the front of the original tube, and the back is about an inch ahead of the front of the gauge so that there are no changes from the gauge back.... The ends of the tube are threaded 13/16-28, the same as the stock Disco tube, and the end plugs are already installed as each unit is pressure tested to 3000 psi before shipping.... The rear end plug is nearly flush, and the front plug contains a male Foster QD fitting.... There is a new front end plug for the Disco reservoir, and a bushing sealed by O-rings between them that transfers the air from the lower tube to the upper.... New black Delrin end caps are supplied for both tubes.... I disassembled my kit and cleaned and polished the tube before bluing it.... I then reassembled it and fitted it to my existing 9mm Disco.... Here is the assembly before dropping it into the stock....

Lloyd's company is called "AirGun Lab", and his website with all the details can be found at http://www.airgunlab.com/ .... There are several videos on the website, and you can see just how simple the installation is by watching this video....

It only took Lloyd just over 7 minutes to install the Disco Double kit including everything except routing out the stock for the lower tube.... For those of you who don't have the equipment to tackle that job, Lloyd has arranged for that also (info on the website).... I made arrangements with Lloyd for a new Disco stock already routed out, so all I had to do with that was throw some stain on the inside and waterproof it.... One of the pleasant surprises was how light the new setup is.... Although Lloyd says the kit will add about a pound to the weight of a Disco, in fact by the time the stock is hollowed out the net gain is quite a bit less.... My new Disco Double weighs only 6 lb. 10 oz. including the scope and mounts.... and balances right in the middle of the forestock.... For a gun of this power, anything under 7 lbs. is a bonus, IMO....

The machining on all the parts in the kit is first rate, and everything fits together perfectly.... I purposely didn't take photos of everything apart or do detailed assembly instructions to encourage you to visit Lloyd's website and look at the assembly video.... You will be amazed at the simplicity.... which to me shows just how much thought went into this clever design.... Final production arrangements are being finalized, and the price will soon be announced.... For anyone who has a modded Disco and wants to get back the shots they lost.... or even if you have a stock one and want tons of shots.... the Disco Double twin-tube kit is highly recommended....

Bob

dk1677 · « **Reply #1 on:** March 26, 2012, 08:51:38 PM »

Great work Bob!

rsterne · « **Reply #2 on:** March 27, 2012, 01:49:09 PM »

I topped up my SCUBA tank and got a chance to do some shooting last evening.... The valve screws on this gun have been upgraded to high tensile 10-32s to insure safety with a 3000 psi fill.... I adjusted the RVA until the first shot at 3000 psi was 800 fps with the 77.8 gr. EunJins and then shot until the velocity dropped to that level again.... I got 8 shots within a 5% velocity range.... I then tried some 125 gr. Lee RF cast bullets (which are actually 132 gr. in pure lead with 1% tin added) sized to 0.357".... Here are the results....

As is typical, when you go to heavier bullets, the shot string shifts to a bit lower pressure, and to stay within the same 5% range, I would only fill to about 2850 psi instead of 3000 but I got 9 shots.... The total air capacity of the Disco Double is about 250 cc (a stock Disco is about 135cc) so the efficiency worked out to 0.90 FPE/CI with the EunJins and 0.95 FPE/CI with the Lees.... The average energy over the strings was 117 FPE with the lighter pellets and 127 FPE with the heavier cast bullets.... with the peaks being 122 FPE (@ 841 fps) and 133 FPE (@ 674 fps) respectively....

The Disco Double twin-tube kit has doubled the shot count, and turned this gun from an interesting experiment to a practical rifle that packs a lot of whallop.... with a useful shot string.... My thanks to Lloyd at AirGun Lab for bringing this product to market.... WELL DONE !!!

Bob

sawtoothscream · « **Reply #3 on:** March 27, 2012, 01:55:26 PM »

looks and sounds awsome. I want to get the kit for mine eventually.

jimmie lee · « **Reply #4 on:** March 27, 2012, 05:48:29 PM »

It still looks a neat, compact package; I don't find the double tube offensive at all. I do foresee a double tube in my future; I'm psychic like that!

lloyd-ss · « **Reply #5 on:** March 28, 2012, 07:37:25 AM »

Bob,
Nice clean looking installation with that special 9mm breech, barrel, and hammer cocking setup. I am pleased to see that your testing validated the increased shot count, which in this case, made the gun noticeably more useful.
Thanks for sharing the information with us.
Lloyd

Tpatner412 · « **Reply #6 on:** March 28, 2012, 11:38:14 AM »

Bob,

I noticed you filled to 3000 psi. Did you modify the valve at all to accept the higher air pressure?

rsterne · « **Reply #7 on:** March 28, 2012, 01:01:13 PM »

The valve didn't need any changes (although I ported it out for more flow), just the mounting screws.... They have been upgraded to 10-32 with a tensile strength of 180,000 psi.... That increases the safety margin on the shear failure of the screws to 4.4:1 at 3000 psi.... The hammer needed the biggest change to get enough power to knock the valve open at higher pressures.... It is heavier, uses a QB hammer spring, and is converted to rear-cocking....

Bob

Tpatner412 · « **Reply #8 on:** March 28, 2012, 01:12:11 PM »

I was always under the impression that the disco would lock up at over 2500 psi or so? Hence my original question. I know they can handle more pressure safely but I wasn't sure about functionality at higher pressures

rsterne · « **Reply #9 on:** March 28, 2012, 03:11:40 PM »

That's why the heavier hammer strike.... to prevent valve lock.... My current setup is capable of getting the first shot to be the fastest at nearly 3000 psi.... so I actually have to dial it back slightly to get the above shot strings.... It is extremely sensitve to preload, the velocity changes about 20 fps in just 1/4 turn on the RVA near the maximum....

Bob

Tpatner412 · « **Reply #10 on:** March 28, 2012, 03:31:11 PM »

Okay that makes sense then. That is some very cool stuff man.

uncle paulie · « **Reply #11 on:** April 10, 2012, 07:32:41 AM »

Nice build Bob, and thanks for the report. Sure looks like the Double is a winner all the way around! Any trouble getting the break on?

pv

gene_sc · « **Reply #12 on:** April 10, 2012, 07:46:58 AM »

Great review on the Disco Double 9mm Bob. Numbers sure tell the story. Double the air, double the fun...

Can't wait to finish mine up.

Gene

blind dog · « **Reply #13 on:** April 10, 2012, 08:48:57 AM »

Bob's build in action:

cheers,
Rob

rsterne · « **Reply #14 on:** April 10, 2012, 12:45:10 PM »

Packs quite a whallop.... *grin*....

RE the question on the brake, the breech I used allows for a 7/8" diameter brake and still clear the air tube.... In addition there is a shoulder on the breech for a 3/4" OD x 0.035" wall shroud.... and the barrel band Lloyd made me will accomodate that - it has an insert stepping it down to the 1/2" barrel OD.... I tried a 30" shroud (nothing inside, just a chamber) and it made little difference to the report.... The brake fitted has no internal chamber, it just finishes off the muzzle nicely....

Bob

blind dog · « **Reply #15 on:** April 10, 2012, 01:08:00 PM »

It looks nice, protects the crown, and is just that much more muzzle stabilization, too, I think. It is very accurate.
Way too much air blast to quiet it down significantly without a firearm type silencer or something major like that.

cheers,
Rob

1chuck69 · « **Reply #16 on:** November 11, 2013, 02:01:15 PM »

Man, I want one of those,very impressive, great work.

grhouse · « **Reply #17 on:** April 03, 2014, 09:20:01 AM »

OK, I'm late posting to this but I'm new to the Forum. I love it. I've got the Disco in 25 CAL and can see where the double would come in handy. I can also appreciate the information relating to the change in valve screws to accommodate the higher pressures. Thanks, Gene

More_Ammo · « **Reply #18 on:** May 02, 2014, 09:49:57 AM »

Quote from: blind dog on April 10, 2012, 08:48:57 AM

Bob's build in action:

cheers,
Rob

That jug just slumped over and bled out. LOL. Nice.

Oldnoob · « **Reply #19 on:** May 02, 2014, 12:04:13 PM »

NICE!

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The 9mm Disco Double

Author Topic: The 9mm Disco Double (Read 26441 times))

blind dog

blind dog

grhouse