Bulk CO2 Mac1 Style

Hangy Tank 4oz mini
The following Crosman models need slight or no mods at all. SA6, 36, 44, 1861, 45, 73, 99, and 500. The use of a Fake CO2/Tank Top and 4oz with or without on off valve will allow all these models to operate independent of 12 grams and have the 4oz tank hanging from where the 12 gram cartridge normally goes. The shot count for each ounce of CO2 is approximately 100 shots.

Czech CO2 Guns
No modifications are required to fit the following models with the Mac-1 Hangy Tank Adapter. Tau 7, Aeron B96, Drulov, Chameleon, Tau 200, etc. We take one of your Piercing caps and make it into a Hangy Tank adapter so you can hang the 4 oz. mini Tank from the bottom of the Pistol grip or the front of the Tau 200 tube. The adapter has a check valve so the gun will stay charged when the tank is removed. It is not recommended that these guns be stored charged unless the o-rings in the gun have been upgraded. The balance for offhand work is really great. Any Gun set up to take a Painball tank will also accept a HPA regulated Air Tank into the same ASA receptacle. This means if it takes a 4oz it can also take a 13 CI 800 psi HPA regulated Tank as well as a Coily Remote. This can be a poor mans Bottle gun with incredible consistency when fitted to good guns with good barrels.

Bulk CO2 extended tube style
Extended bulk can be done to the following models: QB 77, 78, 22, 2079, TF79, Crosman 150, 157, 160, 167, 180, 187, 400, 600, 622/Mac-1 style, 677, and 1100. Mac1 bulk adapter can be fitted directly to any Crosman or QB Tube except the bottle fitted QB guns. The Mac1 extension tubes will fit all the above guns as well and the retaining collar for the end of the tube is different because of the dual threads. Extension tubes are available in 5, 8 or 11”. Our tubes have fine QB threads on one end and coarse Crosman threads on the other so they can be fitted to a wider selection of guns. These are not meant for pressures exceeding normal CO2 working pressures.

4 oz. Bulk CO2 Tank Hanging from Grip Frame

  • No modifications are required to fit the following models with the Mac-1 LD bulk fill adapter: Crosman Mark I, II, S&W 78, 79, Daisy 780, 790 and 41. Bulk adapter will fit any of the above models and works best with 4oz tanks. Can also be fitted with HPA Regulated Air Tanks.

Installing Extension tubes

  • Mac-1's bulk CO2 extensions are made with a QB fine thread on one end and a Crosman coarse thread on the other. If fitting to a QB you should have a fine thread coupling collar and a coarse thread bulk adapter retaining collar. Vice Versa for a Crosman. The alloy sealing adapter with two o-rings on it goes in the end of the tube that will join the factory tube. Recent changes to the QB have the vent hole half way up the threads and a specific sealing adapter must be fitted to those new models designated QB’13.
  • When fitting extensions to any guns with a barrel support loosen the stock and pull the barrel support off the guns tube and slide it off the end of the barrel. Then screw the extension onto the factory tube and snug it. Check factory tube to extension alignment and adjust alignment before final tightening. Slip the barrel strap over the tube and barrel and retighten. Install bulk adapter. Make sure you open bolt before you charge gun. Check for leaks and if all's fine charge gun fully as per instructions.

Bulk Charging Old Crosman CO2 Guns


This is typical question that comes into the Mac1 shop almost weekly




I recently rediscovered my grandfather’s Crosman model 111 (made in the early 1950's) but the bulk filling tank is gone.


I am anxious to get this baby up and running and was wondering if you have a product, or knew of a product I could use that would safely allow me to fill this air gun.


If you have any other info I'd be grateful if you could share it with me.





Early Tanks can have a lot of corrosion inside so if they sound like a baby rattle they are pretty much scrap. If somehow they had gas in them forever they will NOT be Rusty and can be used still. There is no hydro test requirement on vessels smaller than 2” diameter but it does not mean you shouldn’t make sure it isn’t a source of contamination debris for your prized AG’s. Inlet seal failure is all to common and it is always related to Tank or fill adapter congestion & debris. ALWAYS BLOW THROUGH ADAPTERS WITH GAS PRIOR TO FILLING AIRGUNS. Valve down! Gravity sucks and pressure blows. Use it to your advantage when it comes to debris. I would not trust the vessel maintenance at a Painball store.

The best solution is to get a 12 or 20 oz. CO2 Painball tank, fit an On/Off valve so you can control flow, mount up the Tank Top Adapter and you're good to go.

20 oz. tank at Wally world is $20,
Tank Top Adapter is;

on/off valve; http://www.mac1airgunshop.com/co2-on-off-tank-valve-p/co2onoff.htm

You'll spend around $75 to do it.

This would allow the gun to be filled like the Original Tank filled it where the tank sealed in the gun and you make the transfer by turning tank on once the thing is screwed into the front of the gun, Then you turn valve off and unscrew tank from gun to vent off pressure at transfer seal.

The other option is a little more convenient and a little less.

Fill Adapters Galore

  • Transfer adapters to fill small painball type CO2 tanks from master tank.
  • Tank-Tops to adapt painball tank to fill Crosman/QB, directly to the Bulk adapter inlet.
  • Adapter to fill Crosman 10oz or Pilipino style bulk tanks from master tank.
  • CO2 Quick Fill to fill Guns using the Foster Male QC inlet
  • Double male to hook two female Foster Quick Connects together
  • Dead Head to check the pressure of tanks by opening the tanks valve to a plugged yoke.
  • Euro CO2 thread adapters so the adapter to Tank threads are not a huge mismatch.
  • Standard K valve Yokes available with Glycol filled gauge upgrades.
  • SCBA fill Yokes rated to be able to fill the SCBA tank thru the Yoke.
  • 4500 and 3000 psi fill extensions with male and female QC on hose ends

Coily Remotes with or without slide checks for remote tank use