QB-78 to 79 conversion

[SDale]

Is it possible without having to change out the main tube?

[ribbonstone]

Would need the gas block...which has been out of stock at Archers for awhile...cut off the threaded section the 78's end cap screws on with....drill and tap the two screw holes that hold on the QB79's gas block...inlet the stock..drill the stock for the two screws that attache the stock to the gas block...probably best to add the QB79 barrel band.

Even after all of that, would seem very unwise to hang a heavy gas bottle that far out...leverage of the long tube holding up a pound and a half of weight (a full 9oz. tank comes in at close to 24oz.)is sure to cause some problems (besides ssticking out past the end of the barrel).

So, would say that it could be done, but would NOT be good to hang a bottle from.

WOULD be a good idea for an easy way to bulk fill. Add an on/off valve to the gas block. Turn valve on, attach 90z. co2 tank, turn valve off to trap the gas inside the gun, remove co2 tank.

Have been playing with the idea of converting my 78.  Would use a long extenrion gas tube, mount the block and ON/OFF adaptor, and cut the barrel to end even with the adaptor.  Would allow bulk loading from a 20oz. tank as the barrel wouldn't be in the way...and would offer a big gas tube to fill.

[SDale]

Thanks for the info!

I wanted to use the 88g Airsource cartriges & an on/off valve. But now I'm thinking of just modifying the factory cap for bulk fill just as you said. Need to get my hands on an extra one though.

Thanks again!

[ribbonstone]

Have seen posters here who have done just that...added a QD nbippole to  a standard end cap...and that will work just fine for rmote lines.  Bulk fill needs a nipple that will let gas in, but not let it out, but the idea should work.  When i run just from a remote line, I'll take the guts out of the bulk fill end cap, so it is no longer  a real bulk fill....which lets me shoot all the gas in the gun AND the line when i turn the tank off (as a bulk fill, it will leave the coiled line full and you'll have to vent that gas).

Probably 90% of my co2 shooting is with a remote line, even with the QB79.  If i'm at a bench, shooting targets or general plinking, there is no dissadvanatge to havbing a remote line and big tank on the bench with you and the cost of shooting goes way-way down.

I hammered this little rest out of scrap lumber and  a couple of neck braces from ER spine boards (are a use once, item, so when they are opened and not used, they get tossed)...made it to hold a 20oz. tank and it works great for any bench shooting.


Costs?  That 20oz. cost $4 or $5 to fill, and holds as much gas as 46 1/2 12gr. cartridges.

Old post I know, but for anyone thinking of doing this, the best thing to do by far,  is get in touch with Max Balbuena in Honululu and order a Mazbulk adapter for your gun.  It will allow you to fit any tank due to the adapter being offset and also bulk the gun.  He can also put in a gauge tap so you can fit a contents gauge.  He did all this for me for ridiculous sum of $60 US AND deliverd to the UK!!!!  Max's web link is below - he's a superb enginer and a truly nice guy.

http://168.144.194.108/AAMaxZBulk.htm