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PostPosted: Thu Jun 25, 2015 6:08 pm 
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Joined: Wed Feb 11, 2015 3:16 pm
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Location: Ontario,Canada
Just curious what the result would be when using these three components on a stock barrel length 2240...oversize TP..stiffer hammer spring...power adjuster(part #2300-124)??
I am guessing more wasted gas,less shot count per can,a touch more fps,more louder bang.....anything else? Thanks,Huck

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PostPosted: Fri Jun 26, 2015 4:16 pm 
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Joined: Thu Oct 13, 2005 4:20 pm
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Location: sherwood park
Less accuracy from too much gas throwing the pellet off once it leaves the barrel. And probably more hammer bounce.


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PostPosted: Wed Jul 01, 2015 8:12 pm 
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Location: Dowling ,ontario
You'll be getting real close to the 500fps limit ( with light pellets ) I also found the extreme spread got bigger with the factory barrel when I leaned on the hammer spring and used a bigger transfer port , I'm guessing due to liquid co2 expanding at a different rate with every shot.

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PostPosted: Wed Jul 29, 2015 6:10 pm 
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Location: Ontario,Canada
After chronying 30 shots trying out three smaller than stock transfer ports(.110,.125,.136)on my 2240,I decided to go with a much larger than stock(.140) transfer port,this one being.170 I.D.
After 30 previous shots on a new can,I shot 8 shots,using 14.gr CP's,still using a clipped factory hammer spring,I got a 319.2fps average.
I went back to the stock TP. Huck

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PostPosted: Wed Jul 29, 2015 7:27 pm 
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Joined: Tue Oct 13, 2009 1:27 am
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Location: Vancouver
Sounds like perhaps you clipped a bit too much off the hammer spring, without grinding any steel away from the sides of the hammer. The result would line up with what you're reporting, namely too much CO2 being dumped per shot due to the heavy hammer and large port but most of it being dumped after the pellet dribbles out of the barrel at too low a velocity, owing to the sluggish velocity of the under-powered (for it's heavy weight) hammer. The heavy hammer arrives at the valve stem still accelerating but the large port lets the pellet start moving on contact, the duration of the valve opening being too long and most of the CO2 escaping once the pellet is gone. A much lighter hammer with a similar length of spring and a shortened valve stem would likely yield superior results. But Bob might well differ in his opinion on the stem length thing. That's just been my 2240 experience, that the combination of a lighter, quicker hammer with less spring length and preload, coupled with an enlarged TP, ported valve and lighter hammer spring result in increased efficiency.

It is an all too common mistake to modify just one or two elements in the power train and expect system-wide improvements. An RVA alone is often added for example. With the stock barrel all cranking an RVA in will do is waste CO2. Perhaps the opposite would be a useful single mod... but I've yet to see an extended rear cap on the market, bored out or especially made to let the spring have more room. That would almost undoubtedly give a 2240 a higher shot count at slightly reduced power with better shot to shot consistency. Anyone here tried that?


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PostPosted: Wed Jul 29, 2015 8:41 pm 
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After 10 shots with 14.gr CP's,RVA all the way out,I got an average of 355.4 fps and with the RVA all the way in,I got an average of 437.7 fps,using the stock clipped spring.Huck

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PostPosted: Wed Jul 29, 2015 8:48 pm 
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Sorry, but it's still not clear how much you clipped the stock spring. Traditionally one usually clips about half a coil to one coil at a time, testing at each length and recording changes, stopping when there is a slight degradation in performance. From there you adjust the RVA as needed.


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PostPosted: Wed Jul 29, 2015 9:14 pm 
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Location: Ontario,Canada
GerardSamija wrote:
Sorry, but it's still not clear how much you clipped the stock spring. Traditionally one usually clips about half a coil to one coil at a time, testing at each length and recording changes, stopping when there is a slight degradation in performance. From there you adjust the RVA as needed.


I am pretty sure I cut 1/4" off the stock spring which was 2" long originally. Huck

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PostPosted: Wed Jul 29, 2015 9:18 pm 
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Location: Vancouver
Well if it was just 1/4" that is a rather surprising result. Huh. Weird. Now I wish I had a spare 2240 in stock condition to try that on... but other projects call to me first. Well, sorry to near that. But I'm sure in time you will figure out how to arrive at the balanced tune you're after.


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PostPosted: Thu Jul 30, 2015 7:09 am 
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Location: Ontario,Canada
GerardSamija wrote:
Well if it was just 1/4" that is a rather surprising result. Huh. Weird. Now I wish I had a spare 2240 in stock condition to try that on... but other projects call to me first. Well, sorry to near that. But I'm sure in time you will figure out how to arrive at the balanced tune you're after.


Just for kicks,I am going to try a heavier hammer spring with the RVA adjusted in and then out and see what the chrony says.Huck

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