Building the BL-520

[thejackal]

I'm interested in building a BL-520 or near facsimile. But, as the parts from Ultimate Spud Gun are very expensive I thought I would do a little research first. I have many questions. Foremost, can anyone say if USG is even still in business? I've sent several emails but have gotten no reply. There's no post's on their site after 2012. The whole design hinges on being able to purchase parts from that site. Secondly, I think I've secured all the appropriate suppliers for the correct pipe and fittings and cams and such except for one. All the parts in the "Offset Coaxial Kit 520" deal with the rear of the gun, there's no mention as to how to secure the barrel at the front of the gun. Home Depot doesn't sell offset fittings. Is this a proprietary part made by USG? If so there's no mention of it on their site. I thought taking a 5" brass clean out cap might do the trick after cutting off the raised nut, then grinding it flat, drilling a hole and finally tapping it to accommodate a 2" pipe fitting. That seems like a lot of trouble if there's a fitting that can be bought off the shelf. Any info would be appreciated.

[mark.f]

IIRC those offset "bushings" are machined by them, although offset reducing couplings and bushings are common in other countries for drain and waste fittings.

In my opinion you'd be better off building from fittings and pipe you have closer to hand than those used by USG, as they are all fairly uncommon (try finding 5" pipe locally in the U.S., or online for that matter). An "offset adapter" can be machined from either PVC for solvent welding or another, tougher, and all-around better plastic (to be attached with machine screws or threaded). Although you don't have to offset the barrel with the chamber unless you want the extra space it provides for the internals.

[thejackal]

The reason I'm wanting to go "offset" is that is the whole basis for the internal design of this model and the Modular Ring Set's that affix everything are for 5" pipe, although they do have 4" versions. I know what you mean about 5" pipe. I went down to the local plumbing supply and the salesman looked at me like I just feel off the turnip truck when I ask him about 5" pipe, he swore up and down it doesn't exist. Other than talking to a machinist about the offset fitting, I've bookmarked every company that sells the various parts. The question is will they sell a single 10' length of 5" pipe or 1.5" SDR 21 etc. or only in quantity. The guy at the plumbing store didn't even want to talk to me once he found out it was for a toy and that I wasn't going to be buying a truck load of material. I think the best course of action if there are no standard fittings is to just talk to a machinist and let him make one out of solid aluminum or whatever, Thanks for the suggestions.