small transfer port advantage?

[tsmith]

so........

on most FX rifles there is the adjustment for transfer port size. what is the advantage of either?

say i have a .22 cal. whether i want lower power and more shots , or high power, seems like things always work better with a larger port set to .25/.30?

just would like to understand this a bit more.

thanks

 

[SilentSquirrel]

following

 

[spyde82]

I Think its just an easy Way to turn Down power without adjusting your tune

 

[nervoustrig]

Spyde is correct.

And on an unregulated rifle, a small transfer port will give you a broader useful pressure range (high shot count), obviously with some tradeoff in maximum power.

 

[DanielL]

Restricting the transfer port by it's size, on a regulated airgun yields lower power but no more shots. 

FX uses a valve opening limiter on Impacts which reduces power and increases efficiency. On some of their other guns they have a valve spring setting which also increases shot count on lower power settings. 

 

[tor47]

I have not tested it, but if you use a .177 barrel, and shoot low power, using the medium setting on transfer port wheel, might give more efficiency. The reason being the port hole in the barrel will be smaller than the transfer port itself, so using the biggest port setting probably does not give much more speed. All you basically do is add more volume between barrel, and valve, if the port hole is much smaller than the transfer port. That might lead to some pressure drop before the air enters the barrel. 

 

[vmaxpro]

Restricting the transfer port by it's size, on a regulated airgun yields lower power but no more shots. 

FX uses a valve opening limiter on Impacts which reduces power and increases efficiency. On some of their other guns they have a valve spring setting which also increases shot count on lower power settings.

Not sure on fx, but on a brocock I get a major difference in shot count on low/high setting by restricting the port. 175+ on 45 ftlbs and 70+ on 75ftlbs. But like I said it could be apples to oranges. Just my experience. 

 

[0akhonor]

Following, hasn't been much I've seen on this subject for FX guns

 

[tsmith]

Restricting the transfer port by it's size, on a regulated airgun yields lower power but no more shots. 

FX uses a valve opening limiter on Impacts which reduces power and increases efficiency. On some of their other guns they have a valve spring setting which also increases shot count on lower power settings.

Not sure on fx, but on a brocock I get a major difference in shot count on low/high setting by restricting the port. 175+ on 45 ftlbs and 70+ on 75ftlbs. But like I said it could be apples to oranges. Just my experience.

vmaxpro....

not that i doubt you, but ive been told on a compatto you dont gain shot count or save air by using the power setting adjuster. and since the valve is still opening the same amount all that air has to go somewhere? Right?

 

[Mikepr]

Restricting the transfer port by it's size, on a regulated airgun yields lower power but no more shots. 

FX uses a valve opening limiter on Impacts which reduces power and increases efficiency. On some of their other guns they have a valve spring setting which also increases shot count on lower power settings.

Not sure on fx, but on a brocock I get a major difference in shot count on low/high setting by restricting the port. 175+ on 45 ftlbs and 70+ on 75ftlbs. But like I said it could be apples to oranges. Just my experience.

175 shots at 45 ftlb ???

 

[vmaxpro]

Mike, its highly modded. Im no airgun expert by anymeans but I wonder if its a back pressure thing? If you picture the port a pin size hole vs a 1/4” given the same stroke/time theres no way its releasing the same amount of air. Who knows lol

 

[vmaxpro]

Forgot to add, my port is .225. Maybe that has something to do with it?

 

[Mikepr]

You need about 1.5 bar or more for every shot from a 480cc bottle at 45 ftlb
That means 175 X 1.5 =262.5 bar
250-100=150 bar ??? 

 

[vmaxpro]

BIG plenum lol.

 

[kelly1]

Reducing should drop power add shots but no improvement in efficiency.

I have tried it on my airarms tdr and my fx and it is handy indoors or for shooting ft at reduced power and deffenitely more shots as it restricts how much air gets out of the valve before it closes.,kelly

 

[vmaxpro]

My shot count actually increased with a bigger port, higher reg setting, and light weight hammer.

 

[Mikepr]

BIG plenum lol.

Τwo plenums ?
More details /

 

[kelly1]

My shot count actually increased with a bigger port, higher reg setting, and light weight hammer.

Yes ,but thats a tune change not just transfer port,you could come up with lots of different tune with hammer adj,hammer weight, reg adj. and plenum size almost infinite.,kelly

 

[vmaxpro]

Good point kelly. Ive also heard accuracy can be better with a smaller port, is this true?

 

[Yo]

HOLY COW!!! YO!