GTA
General Discussion To Gateway To Airguns => Airgun Gate => : WMassShooter March 25, 2010, 10:22:40 AM
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Hi All-
Trying to decide between a LW 10" or 18" barrel on a .177 Crosman Custom Shop pistol, *edit* with the shoulder stock *edit* -- I have three questions:
1. How many fps do I gain with the 18" over the 10" barrel?
2. Does the sound level change?
3. Any differences in accuracy?
Thanks.
--HL
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You can expect at least 100fps with longer barrel. The longer it get's the quite it shoots. I read from pyramid air blog that you can tell if co2 has not reached it's max if it blast out from the barrel and if I recall, it max out around 19inch the slows down.
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when co2 slows down at 19" or what ever, .... all that means is you need to get in side the valve and do some porting, and opening it up. as far as pistols go, 10" is nice and an 18" is pretty much past nice for a pistol. accuracy should be the same, but with a long barrel and iron sights it would have a slight edge. john
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If you're going to use a shoulder stock I'd go for the 18". Once you get beyond about 12" a pistol gets ungainly and just doesn't look right. A shorter barrel will be louder because there's more residual pressure when the pellet exits the muzzle and there will be some velocity loss but I don't consider either one enough to worry about. Accuracy shouldn.t be affected. Also you didn't mention a muzzle brake. They tend to make a long barrel look shorter and a short barrel look longer. As mentioned in another reply you can always make power mods.
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10 fps per inch is a pretty common figure to use for air gun barrel length vs pellet speed.
The LW will PROBABLY be more accurate, but that does NOT imply that the 18 with be inaccurate.
I have a carbine (from the custom shop) with a 10 and one with a 24 and a pistol with a 13.5 inch barrel. All are nice. It is really a matter of appearance. Valve work can make a 10 faster than a 24 and either can be made just as quite with the correct muzzle break.
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I've started playing with 2240's. Not much difference in sound between a 10 inch barrel and a 14.5 incher. For me, the 10 fps per inch rule of thumb has been a pretty good approximation of the fps difference due to barrel length.