This is a custom .22 caliber, regulated, pcp built by Ron Robinson (highly accomplished shooter and author of 5 airgun books. His first was Manic Compressive and his latest is Awesome Air Pistols!).
This was built on a QB 78 platform and the custom stock was also done by Ron Robinson. The thumb rest on the stock is perfect and the adjustable butt pad is a wonderful feature. It was this gun that Ron Robinson used to take second place in Hunter Class at the 2009 FT National Championships at Yegua Airgun Club. There was a .177 barrel on the gun at that time but Ron installed a very accurate .22 barrel since then.
3 weeks ago, the very competent airgunsmith, nervoustrig went through this gun completely. Here’s a list of what was done:
Work performed
==============
Re-seal:
a. slow leaks present at valve body and at regulator->bottle interface (both size -113 O-rings)
b. regulator spool O-rings were beginning to look suspect (discolored, rough surface)
c. 100% replacement of all seals, down to the check valve O-ring on the Foster fill port
Valve:
a. installed new poppet (OEM type to preserve state of tune)
b. replaced plastic spring guide (glue/epoxy had failed) with brass guide affixed with bearing
retainer (Loctite 638)
c. noted a gap between the valve and the backer block; made and installed 0.040" shim to
prevent valve from shifting under pressure
Deburred parts:
a. receiver: barrel O-rings had bites taken out of them
b. tank block: thru port had taken bite out of O-ring on tank bonnet
c. air tube: to ensure tank block O-rings don't get nicked
Regulator:
a. Tested output pressure before disassembly: 1000psi slowly increasing to 1100psi over period of ~2 minutes
b. Valve seat was dimpled (source of creep). Resurfaced it and dressed it smooth out to 7000 grit.
On reassembly, tested again to confirm setpoint and that creep is resolved.
c. Replaced spool O-rings with cast polyurethane Disogrin type in 90 durometer (-008 and -012)
Reassembly:
a. Thoroughly washed and degreased and dried all parts
b. Applied a thin coat of silicone oil to the pressurized portion of the air tube
c. Burnished molybdenum disulfide dry lubricant to all sliding metal parts
* bolt and its corresponding region in the receiver
* hammer, spring, spring guide, cocking pins
* region inside air tube in which hammer rides
* trigger sear
Chronographed at 735fps with 15.9gr (19.1fpe). Velocity is consistent/reliable after sitting idle overnight (no evidence of regulator creep).”
Since receiving the gun back from nervoustrig I’ve shot 25-30 15.9gr JSB pellets and confirmed that it’s doing 734-740fps and is still very accurate. The little bottle on the gun fills to 3,000psi and gets 70-80 shots
The price includes an effective moderator, rings and a Swift 4-12 scope with A/O that focuses down to 10 yards with a duplex reticle.
I have over 12 pages of feedback on the old yellow boi under kevin lentz so buy with confidence.
Price is $449.00. PayPal FF or goods and services + 3 1/2% fee (my preferred payment method). No trades at this time. Please email me directly with questions; klentz4 “AT” comcast.net
This was built on a QB 78 platform and the custom stock was also done by Ron Robinson. The thumb rest on the stock is perfect and the adjustable butt pad is a wonderful feature. It was this gun that Ron Robinson used to take second place in Hunter Class at the 2009 FT National Championships at Yegua Airgun Club. There was a .177 barrel on the gun at that time but Ron installed a very accurate .22 barrel since then.
3 weeks ago, the very competent airgunsmith, nervoustrig went through this gun completely. Here’s a list of what was done:
Work performed
==============
Re-seal:
a. slow leaks present at valve body and at regulator->bottle interface (both size -113 O-rings)
b. regulator spool O-rings were beginning to look suspect (discolored, rough surface)
c. 100% replacement of all seals, down to the check valve O-ring on the Foster fill port
Valve:
a. installed new poppet (OEM type to preserve state of tune)
b. replaced plastic spring guide (glue/epoxy had failed) with brass guide affixed with bearing
retainer (Loctite 638)
c. noted a gap between the valve and the backer block; made and installed 0.040" shim to
prevent valve from shifting under pressure
Deburred parts:
a. receiver: barrel O-rings had bites taken out of them
b. tank block: thru port had taken bite out of O-ring on tank bonnet
c. air tube: to ensure tank block O-rings don't get nicked
Regulator:
a. Tested output pressure before disassembly: 1000psi slowly increasing to 1100psi over period of ~2 minutes
b. Valve seat was dimpled (source of creep). Resurfaced it and dressed it smooth out to 7000 grit.
On reassembly, tested again to confirm setpoint and that creep is resolved.
c. Replaced spool O-rings with cast polyurethane Disogrin type in 90 durometer (-008 and -012)
Reassembly:
a. Thoroughly washed and degreased and dried all parts
b. Applied a thin coat of silicone oil to the pressurized portion of the air tube
c. Burnished molybdenum disulfide dry lubricant to all sliding metal parts
* bolt and its corresponding region in the receiver
* hammer, spring, spring guide, cocking pins
* region inside air tube in which hammer rides
* trigger sear
Chronographed at 735fps with 15.9gr (19.1fpe). Velocity is consistent/reliable after sitting idle overnight (no evidence of regulator creep).”
Since receiving the gun back from nervoustrig I’ve shot 25-30 15.9gr JSB pellets and confirmed that it’s doing 734-740fps and is still very accurate. The little bottle on the gun fills to 3,000psi and gets 70-80 shots
The price includes an effective moderator, rings and a Swift 4-12 scope with A/O that focuses down to 10 yards with a duplex reticle.
I have over 12 pages of feedback on the old yellow boi under kevin lentz so buy with confidence.
Price is $449.00. PayPal FF or goods and services + 3 1/2% fee (my preferred payment method). No trades at this time. Please email me directly with questions; klentz4 “AT” comcast.net