The 9mm Disco Double

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....

http://i378.photobucket.com/albums/o...iscoDouble.jpg

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.... http://youtu.be/NUNDcLHsDDE

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....

http://i378.photobucket.com/albums/o...iscoDouble.jpg

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

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....

http://i378.photobucket.com/albums/o...coDouble-1.jpg

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

nice machine seams good

That's some pretty impressive numbers, Bob.

How do you feel about it as a grouse gun? Is it suitable for potting those big blue grouse this side of 25 yds?

Post us up some groups!

Regards,

Doc Sharptail

A bit much for Grouse I think, unless you are into decapitating them.... Inside it's putting the boolits into one big ragged hole.... I'll get outside once the snow is gone.... I'll have to shoot it out in the bush as it's too loud to even think about it in town (except indoors with hearing protection)....

Bob

You've still got snow? Coalmont must be interior B.C., then....

I've taken more than one grouse with a jacketed soft-point 150 gr. at 2680 fps, and contrary to popular belief, it doesn't decapitate them, or blow them up- not enough mass on a grouse to trigger that kind of expansion. What I get is .30 caliber holes- in and out- even on the head shots....

Edit: What tears them up badly is the CCI Stinger. I did that once, quite by accident, and I'll never make that error again...

Regards,

Doc Sharptail

Yeah we've still got snow on the ground, and snowing like a b!tch right now.... We're in the Southern Interior at 2500 feet, and where I go to shoot it's even higher and in the shade so the snow stays around until the end of April quite often.... One of the local lakes in the area (Lodestone) is at 6000' and there is often still snow there in June....

I'd forgotten about shooting Grouse with big heavy slugs.... I had Grouse loads for my 30/30 that were 100 gr. at about 1000 fps and when you hit them in the head you often ended up with an inside out skull attached by a few strings.... I never took a body shot with those....

Bob