What was the intention on the bleed valve on the back of the original Tac 8s? And what happens if the Tac 8 pistol does not have one? Consider me ignorant. ...help.
Best,
Smiley
Best,
Smiley
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The purpose is to prevent a hot shot from liquid CO2 getting past the reg (like say a 12 gram being pointed angled down from being in the pistol grip and carried in a holster for an extended period of time), or a large temperature swing (from again, being carried in holster all day, with a cold morning and a hot afternoon), or well both.
If the pistol is used rather constantly, like being your primary gun during your average open play, not having it could in theory be OK, but for liability reasons the manufacturer would say you absolutely need it functional.
Now as an all day long scenario backup gun you pull out for a little close quarters action, and you end up bunkering someone with an unexpected reg creep/temperature change/liquid fueled 450fps hot shot, all because you bypassed the bleed valve, well all that blame is on you now isn't it. -
This is why TIberius said not to use the self defense version everyone was buying for cheap a while back wasn't it? The self defense guns lacked the bleed valve.Comment
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The Tac 8 I thought also had a slightly different setup so it could shoot 450 fps? I didn't think they could be brought down low enough for field velocity.
The lack of the bleed valve is also a safety concern, as Fubarius stated.Comment
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Originally posted by fullofpaint View Post
No, they had them, but were rigged to a higher pressure....Comment
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Great! So how is this different that the other pistols like the Nelspot and the brass Sheridans?
Best,
SmileyComment
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Functionally I cannot comment on (pressure relief by design not actual functionality of the market design).
Legally, they were made in completely different eras. The vast majority of Nelson and Sheridan guns (of the age you are likely referring to Smiley) significantly pre-date the “McDonalds Hot Coffee” frivolous lawsuit age we are living in now that the Tib was designed during.
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Thank you Tony
So overall, how is getting hit by a spiked shot different if coming from a Nelspot or a Tac 8? It's just a question that I have been dealing with and why I reached out to the community.
Best,
SmileyComment
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Oh, and just to clarify, I am talking about the original tac 8.0s, not the SA 8s.
Best,
SmileyComment
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Tac 8s have a regulator, and those act as a back check valve. So if liquid gets past the reg the pressure goes up as the liquid boils off. And can just build and build. How high and how much of a spike this can cause is unknown. Could be rather scary high. A liquid boosted shot on a Nelson or Sheridan, which operate at full 12 gram pressure, gives a maybe 50 fps boost. Not good, but not bone shattering.Comment
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Originally posted by Fubarius View Post
So, if using 12 grams, then what is the point of the pressure relief valve on the Tac 8. Right? Constant air would be the problem then.
Could it be that the engineers were following the AGD design of the automag?
Best,
SmileyComment
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I thought the tac8s had the relief valve and the sr8s did not? I bought one of those cheap sr8s and it wasn’t safe. It would spike when shooting at odd angles and it was hard to turn down
tiberious offered to exchange it for a tac8 since those sr8s were only supposed to be sold to Leo’s.
the tac8 never spiked for me, though I ended up selling it
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Let me see if I can spell it out just a bit.
Regulators. They reduce the pressure coming out of an air source (in this case, a 12 gram, original tac8's never had a constant air option other than adapting a tac9 through the magazine adapter, which meant having to remove and reload by hand the magazine every 8 shots, yikes). They do this by combining the pressure past the regulator with regulator spring pressure. So when those two add up to equal to the pressure in the air source the flow gets cut off (reg piston pushes against reg seat). Can't remember the actual operating pressure of the t8, so lets just assume it's 400psi or so.
So, 400psi + reg spring tension = 800psi from 12 gram.
But when the reg stops flowing it stops it flowing BOTH DIRECTIONS. Hence many guns with regulators will hold a shot or two worth of air after you remove the tank.
Now, CO2 is stored as a liquid. It can only exist as a liquid at the full tank pressure, so 800psi (give or take depending on temperature, assume warm'ish for now). Any lower and the liquid CO2 will start to boil, releasing gaseous CO2, which increases the pressure back up to equilibrium.
So in normal operation, gun fires, pressure behind bolt drops way down, so now post reg pressure plus reg spring is less than 12 gram pressure so reg opens up. Gas flows from 12 gram past reg until it reaches 400psi. Which when added together with reg spring equals 12 gram pressure and reg closes tight. 12 gram pressure goes down a bit (simultaneously to the previous step), a bit of liquid co2 boils off, 12 gram pressure back up to 800psi. And we're ready to start all over again.
Now, the issue is when things don't go quite right. So you point the gun down and fire. Reg opens up, gas flows through, but this time drags a bit of liquid CO2 with it. Pressure gets up to 400psi and the reg closes. But now the liquid CO2 past the reg starts to boil off, releasing gas, and the pressure climbs up. Quite possibly up to 800psi, twice what the gun is expecting. The reg is just a one way valve, it won't let gas flow back into the air source. Hence the pressure relief valve, to get rid of that excess pressure and make sure you only fire with the 400psi (or whatever) the gun is expecting.
This is also why when you are chronoing ANY gun with a regulator and you wish to turn the velocity down you HAVE to fire 2 or 3 shots with every turn of the regulator.Comment
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Constant air doesn't boil to create pressure like Co2, it's a constant state. So no it would not be a problem. A bleed valve for CA wouldn't do much.Originally posted by infamoussmiley View Post
If the Tac 8 has the bleed valve, I'm a little confused then. A google search looks like the TAC 8 was a bundle for the T8. I guess I was thinking of the SA8 regarding the Safety bleed valve and FPS setting.
If that is true the TAC 8 and T8 are the same thing, the TAC 8 just came with "SOCOM" gear (laser pointer and barrel "suppressor").
So ya, the bleed valve on the back just keeps Co2 overpressure under control so you don't have any Hot Shots.Comment
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If you don't mind me hijacking this thread I just given a t8 and have a couple questions:
At rest the gun does not leak but when I pull the trigger the gun shoots once and then free flows down the barrel until the magazine is dropped, and then stops. I assume there is some problem with the bolt engine but can anyone give me a shortcut as to which o-ring(s) to check?
I got three magazines with the gun; two of them have a toolless changer for the cartridge but the third does not. Is there a place to get the parts to make all three toolless?
Is there a way to convert the t8 so that into a t8.1? Is all it takes a new barrel and/or magazines to allow first strike use?
Does the remote air adapter for the t8.1 fit the t8?
Thanks and again sorry for the thread hijack but this subforum doesn't seem very active.Comment
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I've currently got two T9s and I've worked on several T8s. They're all basically the same.
For the T8 to T8.1 there is an upgrade kit that has a barrel, bolt, spring and mag.
For mags there are a few different types. There's an older version that came with the T8/T9s and an updated version that's have the tooless function and is shaped for first strike.
There are a couple different versions of the remote line adaptors. For the T8/T9 series I believe they are only available in the mag. There is an remote adaptor block available for a T9.1 and T8.1 that bolts onto the back fo the market I believe.
As for your gun issues, could be a reg issue or the trigger return isn't working and it's bleeding out. I often find the sear area of these guns gets really gunky and gross and these work much better once they have been cleaned. If it's helpful I can do up a teardown thread on my T9 I'm working on fixing.
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