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hth 11-06-2012 08:45 PM

Trifluted hammer + co2= low fps?
I was going to play stock class Sunday but I found a problem.

Using co2 I was maxing out at 160 fps, however I would get 260+ when using hpa.

So I am running a phantom with : back bottle valve, trifluted hammer, red spring, ported tpc (could put in oring but didn't), and a Lapco .681 barrel. I'm stumped on what is going on

cobyrne 11-06-2012 09:01 PM

What was the temperature where you were playing? Perhaps, it's too cold for the co2 and you may need to go back to the stock hammer to get the valve to open up a bit more?

Or, is your pierce pin dull and you're not getting a good puncture on the 12g (ie. you're not getting enough co2 into the valve)?

-=ArchAngel=- 11-06-2012 11:53 PM

a fluted hammer in general is suppose to lower your FPS. However, that low? Probably not. Im guessing its due to the cold. CO2+cold = poopie velocity.

idkfa 11-07-2012 12:07 AM

Am I correct in saying that you tried a bulk CO2 tank and a HPA tank when experiencing the FPS drop? You mention stock class but didn't specify that you were using 12 grams for your test.

If you are using a bulk tank, check that your pin valve isn't being choked off. If using 12 grams, follow cobyrne's advice above.

I can't imagine ambient temperature causing that severe of a drop. I have used a 3.5 oz tank in -10C and only dropped to 250 fps or so before adjusting my springs.

hth 11-07-2012 12:43 AM

It was using a twelvie at about 10*c. And yea I'm thinking that the hammer may not be hitting hard enough due to lower weight.

So the remedy is to go with stock hammer or lighter valve spring?

cobyrne 11-07-2012 06:11 AM

10*C shouldn't make that 100 fps difference between a 12ie and hpa. I suspect it's your pierce pin - either it's not puncturing the cartridges well enough or it's plugged somehow.

Are you seeing a reasonable sized hole in the tops of the spent co2 cartridges (ie. the hole is bigger than the hole you see in the tip of the pierce pin)?

Also, are you using a trracer bba? They have a copper/brass (?) mesh in the transfer port (which the gas passes through to get into the valve chamber) that can get clogged over time and may be choking your valve.

If all that is fine, you could start with either a lighter valve spring or the stock hammer to see if that makes a difference. If it doesn't then your problem is likely with the valve getting enough gas pressure.

hth 11-07-2012 08:49 AM

I'm almost kinda glad I have 2 phantoms now so I can swap parts and see what's up

idkfa 11-07-2012 12:25 PM

My money is on your problem being upstream from your valve. It is the pierce pin, pierce seal, or the powerlette itself. What brand of powerlettes are you using?

Listen to cobyrne and work your way through his post.

hth 11-07-2012 08:38 PM

Well I was using crosman ones, maybe a Titus one as well. I will try again with another 12g changer first before resorting to a hammer change

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