For QB7X is there an aftermarket lighter spring

Joined: February 23rd, 2012, 12:42 am

December 16th, 2015, 2:22 am #1

Or does everyone just clip coils.
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Joined: November 30th, 2006, 2:44 am

December 16th, 2015, 3:31 am #2

It's been years since I messed with mine. Yes, you can clip or I may have gone to Ace Hardware and purchased springs.
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Joined: February 8th, 2014, 10:17 am

December 16th, 2015, 11:28 am #3

I clip the coils as it's easy to put back with a washer or two if needed ,
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Joined: December 18th, 2009, 3:35 pm

December 16th, 2015, 1:38 pm #4

Or does everyone just clip coils.
All I needed was a dremel and a power drill to do all the lightening I needed.

Bruce
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Joined: February 23rd, 2012, 12:42 am

December 17th, 2015, 12:19 am #5

Or does everyone just clip coils.
that somewhere there was a drop in spring that people were using, a lot of pcp rifles seem to have found some off the shelf not intended for airgun use spring that works.
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Joined: December 18th, 2009, 3:35 pm

December 18th, 2015, 12:24 pm #6

and waste air.

The goal or reason to lighten the striker is primaryly to decrease hammer bounce.... but hammer wieght is also a factor of spring and valve design/weight.

For example if you are using the stock valve you need pop power to pop the valve open so need more spring or hammer weight. If you change the valve to have a delrin popit all a suden with no other change will use more air. This is because how the different light valve is affected.. You will also often end up with ou gun getting really loud due to the hammer bounce and increased valve lift and air it will provide.

There needs to be balnce to what you do between the Port size, popit/valve head, hammer weight and also the amount of hammer spring.

Bruce
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Joined: March 28th, 2002, 6:54 pm

December 18th, 2015, 6:06 pm #7

that somewhere there was a drop in spring that people were using, a lot of pcp rifles seem to have found some off the shelf not intended for airgun use spring that works.
I put a lighter spring in a 78, intended for a woman with very little hand strength (I can cock it with my index finger alone)and I had to make several other changes to get a decent tune with low bounce, even though the gun had worked well before the spring change.

The spring I used was from the spring packets at my local hardware store, and matched in length and OD, but had a wire size .003" thinner.Velocity dropped into the low 700's in .177.
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Joined: February 23rd, 2012, 12:42 am

December 19th, 2015, 4:54 am #8

So i will have to look at lightening the hammer first, sounds good.

Thanks, Garth
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Joined: March 14th, 2012, 8:19 pm

December 19th, 2015, 9:35 am #9

Bought mine as a heavily modified unit, apparently intended to be a sort of elongated hi-power pistol, but had no interest in a loud and air-wasteful 28fpe pistol, getting only 3 or 4 useful shots from 1,500psi HPA, which was too heavy to hold with one hand. Unbelievably loud! Absurdly so, like a .22lr pistol shooting subsonics. So much wasted pressure with the stock hammer and spring, and the ports and valve opened right up.

So I converted it back into a carbine and set to work tuning it more sensibly. Carved a LOT of hammer weight away, squaring three sides of the hammer and leaving minimal contact surfaces just to guide it down the cylinder. Polished that. Cut some of the stock spring down and polished the new end. Added a bit of preload spacing to get the tension on the hammer back up. Opened out the valve, changed to a delrin poppet, swapped out to a longer, lighter valve spring. Can't recall what all else, but anyway it's shooting very consistently at around 19.75fpe in .22", very little power difference between 14.39gr and 18.13gr JSB pellets going through the ~13.4" barrel. I'm getting 8 decently even velocity shots from a 1,300psi fill. Will be adding a regulated Ninja bottle preset to about 950psi output so I can shoot all day on one fill. It's proving accurate enough that it's probably my new field target club gun. Trimming steel off the hammer was probably the most significant mod. Oh, and I added a little U-shaped debouncer I made, following some images I found in the yellow somewhere. Could have ordered one from Archer, but I like to get my hands dirty when I can so I spent too much time and made one, got it right on the first go, and that really helped in eliminating waste and noise. Only a hair over 60psi lost per shot from the small stock tube.
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Joined: March 28th, 2002, 6:54 pm

December 19th, 2015, 5:45 pm #10

That sounds like a very well balanced tune.
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