Reply With QuoteVery unusual fault I must say. I can only think of two main causes.
1. a worn second notch on the piston
2. a broken mainspring ... ( has it been dieseling.?? )
Pete.
Registered User
Only had it since April this year, and can now only cock it to half power. Don't use full power usually as I only have 20ft indoor range, but like to mess with full power sometimes. Anyway, got in touch with guy I bought from, and he reckons the quickest way is to phone Hull Cartridge, and have them collect it for repair or replacement. Phoned this morning and left a message on answer machine (Being Saturday). Just hoping they get back to me asap. Gonna miss it while its gone!!! I'm a bit disappointed that a fault should occur at less than a year old. Anyone else had this problem?
Knowledge is knowing a tomato is a fruit. Wisdom is not putting it in a fruit salad.
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Very unusual fault I must say. I can only think of two main causes.
1. a worn second notch on the piston
2. a broken mainspring ... ( has it been dieseling.?? )
Pete.
Registered User
It did in the first few weeks, but then settled down. Seems to be ok just on half power, although theres a bit of a crunchy sound on cocking. I can open cocking arm all the way, but I have to force the last inch and it won't lock into last position. Would have thought the first notch would have worn as thats the one I use mainly but no, just full position! Can't see anything obvious, so will have to go back to Hull Cartridge. Very disappointing. ATB. Pete.Originally Posted by flatrajectory
Knowledge is knowing a tomato is a fruit. Wisdom is not putting it in a fruit salad.
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Mine did it a couple of weeks after warranty finished, Sportsman Gun Centre split cost with me. Took a few weeks and £40 and never told what problem was seems fine now though
Guest
Sounds very much like a broken mainspring, caused by dieseling. What happens then is the broken coil/coils wind themselves into the rest of the spring and cause `binding`. As it is under warranty you should send it back.
Pete.
Registered User
I believe its possibly the second detent on the sear engagement. Only came across it once. Its easy to change out the detent but getting the spare maybe more tricky.
Could try Knibbs or chambers.
Registered User
Just spoke to a nice chap at Hull Cartridge, Who reckons second detent sounds right. They're collecting my 45 tomorrow for repair, so got the ball rolling at least. He also says spring can't be broken through dieseling ( don't shoot the messenger) . ATB. Pete.
Knowledge is knowing a tomato is a fruit. Wisdom is not putting it in a fruit salad.
Registered User
Well ive been working on them for 17 odd years and not known a mainspring go. Looks too substantial and well tempered in relation to the half strength loading and forces relative to what a rifle gets.) So i would tend to agree.
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Any mainspring can break due to excesive dieseling, ask JT. !,,,
Pete
Registered User
To an extent that's true of course but in the case of pistols, the return from dieseling and other forces is approx half that (or considerably less) than their rifle equivalents but the mainspring of the 45 is much better than half the toughness/strength of an air rifle. Ive never heard of one breaking across some 20 years but i suppose someone might know of it happening somewhere. Just putting things into perspective i have know of 4 Supersport springs go. Could have been bad batches used by BSA in the mid 90s. Actually heard a HW80 go one time.
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They're going to give me a report on what the problem was apparently when returned, so will let you all know. Trouble is at this time of year, I don't know how long that might be. Hope its soon but, could be after christmas hols. ATB. Pete.
Knowledge is knowing a tomato is a fruit. Wisdom is not putting it in a fruit salad.
Guest
Clarky,
The above is absolutely correct. I have been repairing/restoring air guns for 30 years ( for gun shops), so have seen many instances of broken mainsprings, bulged cylinders etc. caused by excessive diseling. For the most part they were confined to rifles ( as you say ), but there were still a fair few pistols damaged in this way.
In my first reply to the o.p. I did suggest a worn notch/detent on the piston as the other likely cause, but I would be surprised to find that on a fairly new HW, as I have never come across it myself. The fact that Hull Cartridge have suggested it may point to it being a not uncommon occurance.!,,,,
We shall see.
Pete.
Registered User
Nice one, i wouldnt disagree. Just havent come across it on the 45.
As a fellow repairer you might be interested in my findings and rebuild of the HW75. Maybe you have some experience of it too.
I have put in a longer barrel to the muzzle for 25fps increase. Cleaned out excess lubes for around another 10fps. I have noticed the later models have a chamfer to the front of the piston, presumably as an aid to installation at the factory but im thinking its costing in the form of dead space. Maybe my imagination but im sure the older version is slightly tougher to cock and giving around the same velocity of my modded one which was barely doing 390fps before i modded it.
Next xmas project might be to turn up a new charging piston without the chamfer then.
Guest
I never worked on a HW75 in all my years, so cannot comment on any improvements.
As to the chamfer on the piston, whilst there may be some 'dead 'space involved I would imagine this to be so minute as to be of little difference to the performance. You would probably get more difference in muzzle velocity between lubed and unlubed pellets for instance. Of course this is an educated guess, and the only way to prove otherwise is by experimentation. This what makes our hobby so absorbing and fascinating.
For instance I discovered many years ago that Airsporters ( mk3-6 ) show an improvement in power, smoothness and accuracy by shortening the standard mainspring by one and a half coils. ( in most cases).
Pete.
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