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All Springer/NP/PCP Air Gun Discussion General > PCP/CO2/HPA Air Gun Gates "The Darkside"

2260MB Tubes with Ground Finish - DO NOT USE FOR HPA

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rsterne:
I just found this warning from TKO22.... I have no first hand knowledge of this, but PLEASE check this out if you are considering using HPA on a gun equipped with a 2260MB tube.... Even bulk filling with CO2 would be questionable, as the safety margin if the gun is left inside a hot car would be less than 3:1.... CO2 can reach 1900 psi at 120*F....


--- Quote ---TKO22 SAYS:

The Crosman 2260 air tube has recently been changed by Crosman.

The new tubes are marked: "2260MB".

These ARE NOT THE same as the old 2260 tubes. They are 0.049 wall and machine very differently than the old "2260" tubes (0.065 wall). The 2260MB tubes also have a hard step at the front threaded end that will make it very difficult to get it to seal with a Discovery fill adapter. The 2260 tubes are chamfered for a smooth squeeze on the adapter o-rings.

I have hydro'd a couple of the newer 2260MB tubes, and they failed at ~4100-4600 psi. In each case, the fill adapter blew out the front.

I have assembled about 50 PCP pistols and carbines over the course of 5-6 years, using the 2260 tubes and no failures reported. I wouldn't use a 2260MB tube except for a Co2 cartridge gun.
--- End quote ---

If this is in fact true, this thread should be made a sticky, IMO.... Stay Safe !!!!

NOTE: This appears to have been caused by Crosman grinding down the OD excessively on some 2260MB tubes during the finishing process.... Do NOT use these tubes with a ground exterior finish for either bulk fill CO2 or an HPA conversion, as the wall thickness may be uneven and thin enough in places to be unsafe at increased pressures.... See Reply #45 on Page 3 for details....

Note, these tubes are fine for use with 12 gr. CO2 cartridges, as intended, because the tube is not under pressure....

Bob

d_ray50:
I sure hate that I just last week bought a 2260MB Sheridan tube from Magnum Airpower {Bill} set up for HPA and have all the parts ordered for complete HPA gun. I will contact Bill and see what he says.

d_ray50:
I just got off the phone with Bill - Magnum Airpower he said 2260MB tube same material and thickness as Discovery , 1720T etc. and that he has tested them to be sure . Sounds good to me .

Ribbonstone:
Don't have any new Crsoman tubes...but if the numbers are right, then I'd certainly pass on PCP use.


Don't really have a horse in this race,  no Crosman tubes under pressure (air or bulk fillco2) so no personal envolvment pro or con.

TKO22:

--- Quote from: rsterne on March 08, 2019, 12:54:59 PM ---I just found this warning from TKO22.... I have no first hand knowledge of this, but PLEASE check this out if you are considering using HPA on a gun equipped with a 2260MB tube.... Even bulk filling with CO2 would be questionable, as the safety margin if the gun is left inside a hot car would be less than 3:1.... CO2 can reach 1900 psi at 120*F....


--- Quote ---TKO22 SAYS:

The Crosman 2260 air tube has recently been changed by Crosman.

The new tubes are marked: "2260MB".

These ARE NOT THE same as the old 2260 tubes. They are 0.049 wall and machine very differently than the old "2260" tubes (0.065 wall). The 2260MB tubes also have a hard step at the front threaded end that will make it very difficult to get it to seal with a Discovery fill adapter. The 2260 tubes are chamfered for a smooth squeeze on the adapter o-rings.

I have hydro'd a couple of the newer 2260MB tubes, and they failed at ~4100-4600 psi. In each case, the fill adapter blew out the front.

I have assembled about 50 PCP pistols and carbines over the course of 5-6 years, using the 2260 tubes and no failures reported. I wouldn't use a 2260MB tube except for a Co2 cartridge gun.
--- End quote ---

If this is in fact true, this thread should be made a sticky, IMO.... Stay Safe !!!!

Bob

--- End quote ---

I have three tubes in front of me:

A 2260MB, a Discovery and a Maximus tube.

The 2260MB tube wall is .049. OD: .863

The Discovery tube wall is .063. OD: .875

The Maximus tube wall is .065. OD: 874

Average of 3 measurements each.

Probably the same material as they machine identically, but not the same dimensions.

It would be a good idea to measure and verify dimensions with any 2260MB tubes you are considering for a PCP build.

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