Tau 7 bulk fill

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bandur60
Posts: 56
Joined: Mon Feb 27, 2012 3:26 pm
Location: Big Sky country

Tau 7 bulk fill

Post by bandur60 »

I've looked on the CZ site and think this is the right adapter, called a "filling valve CO2". Is this what we need to fill the bulk tanks that came with our Tau 7 Jrs? I searched this forum and found several related queries but nothing like I'm trying to find. There was an adapter called "Cooper T" that works with the Daisy 888/887 fill adapter, but that seems unavailable too. We have 6 or 7 pistols that can be set up for this but no adapter to be found. (The CZ adapter looks to be about $17.50 USD before shipping from the factory.) Am I on the right track?

I also looked at Pyramid Air and Airguns of Arizona.
97nick
Posts: 72
Joined: Thu May 09, 2013 4:20 pm
Location: angus scotland

Re: Tau 7 bulk fill

Post by 97nick »

I had a Tau, and had a bulk fill adapter with it, looks like the filling valve c02 is the one you need. I must say though I never had good results from bulk filling and used to just use the 12grm caplets
Gwhite
Posts: 3427
Joined: Sat Sep 04, 2004 6:04 pm
Location: Massachusetts

Re: Tau 7 bulk fill

Post by Gwhite »

The MIT collegiate team has been bulk filling Tau's for years with good success. There is a really good exploded diagram here:

http://www.74fdc.files.wordpress.com/20 ... ploded.jpg

The thing you need to go on the CO2 tank is what they call "VENTIL B-B CAN", consisting of part #83, and a couple O-rings (#64 & #90).

If you want to be sure, send them the part #'s to verify.

For bulk filling, you need to make sure you get a CO2 tank from a good industrial/medical supplier who can provide you with a good clean tank (NOT a recycled soda fountain tank with rust inside) with a "siphon tube". Chill the small "bottles" in a refrigerator, and then put them on the big tank with the adapter, and open the valve for about 10 seconds. That should give you pretty close to the full weight. You need a good digital scale to weight the bottles to see how much CO2 they have in them.

When you fill the pistols, screw on the bottle, and let them sit for about 2 minutes upside down. The liquid CO2 has to flow down through two valves (one on the bottle, and one in the fill adapter on the pistol), and the passages are small. The pistols can take about 15-17 grams of CO2 with no cartridge inside. Check the weight of the fill bottle afterward to see how much you got into the pistol. Another approach is to weight the pistols empty, make a note of it and then weight them when they are filled. That is especially useful when you want to top one off, but don't know how much is still in the pistol. Depending of the velocity setting, you should get about 7 shots per gram, so 10 grams is a minimum for a full 60 shot match with sighters.

We have a wide range of vintage bottles & pistols, and some combinations don't always work well due to minor design changes. If the pistols are used in formal competition where you can't release gas during the prep period, you'll need some of my dry fire adapters, or you have to dump all the CO2 to dry fire. See http://www.targettalk.org/viewtopic.php ... on#p166476
yana
Posts: 359
Joined: Mon Sep 20, 2010 9:58 am
Location: netherlands

Re: Tau 7 bulk fill

Post by yana »

Dont bulkfill.
It has no advantages.
No extra shots only more hassle cause you dont have temperature differences
Just use 12gr bulbs.
If you really want an adapter, simply order 1 from Tau directly through their website
Gwhite
Posts: 3427
Joined: Sat Sep 04, 2004 6:04 pm
Location: Massachusetts

Re: Tau 7 bulk fill

Post by Gwhite »

Pardon me, but you have no idea what you are talking about. We have roughly 20 Tau's we bulk fill exclusively. They hold more than 12 grams of CO2 without the cartridge in place, so you DO get more shots. You also don't have to juggle between two piercing caps because you aren't constantly depressurizing the O-rings. I regularly have to replace the O-rings for local individual shooters who use cartridges.

An individual may not want to bother with a large CO2 tank, but if you are supporting a team with more than one Tau, bulk fill is the only way to go. The original poster mentions "Tau's" (note plural), and having swapped emails with him, he is involved in a program that already has a CO2 tank for other pistols.
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