Crosman 140 and the 12 ft/lb limit

[Dan944]

I have a few of these and like others here have said are a pain to limit power on. I grafted a new Crosman barrel on one of mine and it's a joy to pump and shoot but is on hold in bits again till I have the time to make it an adjustable pump head with blow off valve inside, as I think that's the only way I personally will be happy shooting it.

I'm not one for wanting to pump 15 times so I like to get pampers as efficient at making 11ftlb but have a system to not allow any further power such as hammer spring reduction or in this case the way the valve works you need to go down the blow off valve type head/piston in order to get this a worthwhile serious rifle, otherwise as others mensioned you would have to shorten the pump rod so that it has a gap big enough between piston and valve head as not to be able to squeeze all of the air into the valve and hence keeping under the legal 12ftlb limit and thus requiring a lot more pumps and I should imagine allot of time tweaking to get to this point !

In my experience most decent pumpers really need allot of attention and testing as they are easily nudged over the limit and need regular testing to make sure this doesn't happen and can't happen so lockthread on any adjustment nuts ect, as I've had a few of my innovas set just under 11 and few years later got them out and they went just over, so I always Chrono mine before I ever take them out to the club for piece of mind.


I love pumpers

Atb
Daniel

[johnbaz]

If I recall correctly, The 14** series of guns were capable of going over our legal limit and in fact, Would pump until they would lock up and the valve wouldn't open resulting in the need to strip the guns to let the air out!, Later upgrades included a blow off valve to stop this happening (May be wrong though!!)


Cheers, John

[Phil B]

That was my understanding too.

Does anyone know if a later piston and which model type would fit??

It'd save making something. Anyone made a donor piston fit fron Sharp/Webley etc???

Thanks.

[--ped--]

the valve is a dump valve and will open no matter how many pumps John it was brought out as previous models were over pumped and suffered valve lock and the 130/1300 140/1400 was crosmans answer to the problem
piston wise an aftermarket ftp will fit if a longer rod is used but nothing commercially made with a pressure valve is available
I have made one as a prototype but not got round to going further with it as my 140 needed a new trigger blade and I haven't fitted the new one yet
I have since acquired a beat up one but the lever link rivet is buggered so once I have fixed that i'll use the poor condition one as a test bed and do some tests

[Phil B]

Interesting stuff Ped.


ftp? Flat top piston?? From where, yourself?

Thanks

[--ped--]

I have them in stock in delrin for 13xx guns but the 140 would need an imperial threaded head making to use the existing rod and I'd probably use brass instead of delrin

[DT Fletcher]

All correct about the models 130/140 being the answer to "Valve Lock" failure of previous models 107/108, 109/110, 120. Prior to that, the 101/102 models, with their external hammers, could be "unlocked" externally. At Crosman, a gun that had been returned to the factory and was found to require any actual repair to make it operational, it would be determined to be an Engineering-Design issue.

The first blow off valve guns had what was called "fingertip recocking" where the valve was manually pushed back in place. It was actually a Crosman manufacturing floor supervisor who suggested that the design could be further simplified by placing a spring behind the valve to achieve automatic recocking.

It's interesting that the Benjamin Air Rifle Co. never bothered with anything like this, although their guns would be subject to the same issue. Most likely this was because there was never an Engineering Design department at there. Instead, it was always Benjamin top management who moonlighted as designers.

[45flint]

Being from across the ocean but very near Canada I wonder how you work a gun like this? I heard from a friend crossing the border into Canada the guard looked at the box to check power. But what do you if you have altered the gun to limit power? The authorities would have to test it, given I assume they wouldn't take your word for it? Is that really doable, would they certify one gun? How do they know you wouldn't go home and make it original again? Just seems unworkable to me?