...it is. Very large tube (1 5/8" O.D.). Probably won't make more, unless an invidual out there would like to copy the design and sell them. Would be willing to send the gun(s) to a known builder on the forums to tear down and take the measurements and what not.
The main concept on these guns is to use other gun parts for that custom look. The stock is an airsoft M4 buddy stock collaspable six postion, paintball trigger frame, Crosman design breech (many makers out there make them). Dont get me wrong, because it uses an airsoft stock and PB trigger frame that they are cheap in quality. The main design element is in the tube, end plugs and valve. If someone wanted to make the main cetral part of the gun and sell it, the buyer can choose from a plethora of parts avail. online and from Crosman to finish it. Thus, the idea is price minded.
I won't have two complete guns in the end. Parts will swap out to make the Indy clone. The only difference in the clone gun is the end plug, valve plug, and piston assembly. For now, starters, the PCP will be finished first.
On tha barrel I made up... Used a smooth bore barrel and pressed six exterior grooves 60 degrees apart radially. The gooves did transfer to the interior of the bore. The gooves are 1/2" long and at 13 degrees along the axis of the barrel at the muzzle. Currently the barrel is on a 1377 carbine and shoots like a dream. To prevent over stamp in the bore, used was a brass rod that fit the bore snug. Had to twist it out to free it. Conducted several water test to look at the pellets, barrel checks, etc. All seems very good. Would like to get a look at the pellets in flight, but do not have the camera system to do so.
Yes, an airsoft mag works just fine for .25 cal lead. Do not use a "wind up" mag - they are not worthy. Get a "mid cap" mag. They hold anywhere from 80-200 rounds and they stack the BB's in a double stack continus column like a real magazine. They feed in a flawless manner.
Speaking of that, I did build another little air motor (pneumatic actuator) since we last chatted. Built it in case you needed a reference how to create an autoloading recipricating unit. Cycles about 20-25 a second on 90 psi. Now I need to make a gun out of it (airsoft).
"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."