GTA
General Discussion To Gateway To Airguns => Airgun Gate => : ribbonstone October 27, 2006, 04:24:33 AM
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Loking at energy figures for light vs. heavy weight pellets and collecting data. The ENERGY numbers for the light weight pellets have been pretty close tot he heavy weights, with occasional exceptions...mostly low readings...from cheap pellets that just don't fit the bore well.
For a number of years now, the .177/.20/22 Benjamin/Sheridan's have all been built with the same power plant..no internal differences, just a different sized hole running though the barrrel. That certainly isn't true of the older guns, and while they fall pretty much in line with the modern gun's figures, are excluded to keep it as close to apples-to-apples as possible.
Tossing out the old guns leaves 7 rifles (3 22's, 2 20's, and 2 177's). The energy of the lighter weight .177 (7.4fs.) and the heavier weight (10.5gr.) is within 4/10ths. Call it 9.6 to 10fpe+
Get 11.5 to 12.2fpe+ from a .20cal, the weight variation runs from a light pellet of 10.3gr. and the standard 14.3gr. pellet.
The .22 pellets ran from 21.4gr. and 13.4gr., but produced only a 1/10ths differnce in energy (13.4 and 13.5fpe+).
Springers don't seem to work this way; more complicated ballistics and pressure generation. Have found some springers that make much better use of their system in .177's (the FWB 124) than they do .22's (the FWB 127) and belive that the modern rifles offered in the +1000fps range would be worth a hard look in .22...IF YOU COULD GET THEM! (disturbs me to see so few .22's as an option).
But given a fixed volume of high pressure air, multi-stoke pneumatic or pre-charged, the larger caliber justs get more out of the contained energy than the smaller calibers.
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Yep..can get them rebuild and magnumized....belive that the larger caliber will continue to out perform the smaller calibers if the same work is done to each. Given a fixed volume of high pressure air, the larger bore just seem to make better use of it .
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Very intersting. I never had thought about a .20 air rifle until JP Shelton wrote about his .20 Beeman rifle and how suited it was for what he used it for. I began searching for a lite weight .20 caliber rifle but it seems the manufacturers do not make them. Could be because of the marketing aspect.
After JP Shelton posted about buying a Shadow 1000 .177 and how impressed he was with it and CDT's Trigger. Just after this Rich introduced the .20 L/W choked barrels I bought one to put in one of my Shadow 1000 .177. Initially my idea was to have a .177, ,20 and a ,22 in the Shadow series. After the installation of the .20 L/W choked barrel in my Shadow did I realize this gun was the best of both the .177 and the .22. In fact that is the first rifle I pick up for paper shooting. It does not get anywhere near 1000 fps with the 11.4gr fts pellets I use but does have a respectable average of around 860 to 875. The deviation is small and helps support smaller groups.
On the other hand I with the .22 springers out there now, the manufacturers need to tame the recoil abit in order for the average guy like me can hit something...:)
And both my FX Cyclone will shoot over 800 fps with a 14.7gr RWS Superdomw. And the Samatra shoots 30gr pellets up 1000 fps with 63fpe.
Oh an I almost forgot the Arm Buster..:) Gamo 1250 .22. It shoots in the low 1000's with the a 14.7 RWS Superdome. Now I think it would be a much better shooter if I could figuer out how to de-tune it a bit..:)
I do not have enough experience or knowledge to intelligently understand what all this means but it sure is a heck of allot of fun... he he he
Gene
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Like the switch-barrel feature possible with some airguns, would be interrested in testing the exact same power plant in three different calibers (or add in the .25cal. and make it 4 calibers). Suspect the most energy efficient would be the .22, but with springers there are factors besides simply the volume of air.
Springers are certainly the most efficient air rifles in terms of energy put into the system vs. energy gotten out. CO2 shooters tend to forget that someone, somewhere had to use a good bit of energy to make and transport the carbon dioxide...same for PCP shooters who don't hand pump.
Have found the .20 to be a caliber worth investigating. Kind of an orphan in he airgun industry right now. Deserves better than that.
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Hey, Ribbonstone,
Talk to Rich from Mich about putting together a 3 or 4 barrel set for a CFX. He recently posted about installing a match LW .177 barrel on a CFX, and indicated that putting together a multi barrel set might be a reasonably doable thing. From his post, it sounds like swapping barrels could turn out to be relatively simple. This has rekindled my interest in a gas ram conversion. Imagine a CFX with .177, .20, .22, and .25 barrels, and a gas ram rated at 18 fpe. That's what Theoben USA says the new FAC rams are supposed to be rated at. Put it all in a fancy custom case, with custom stock, and you have a set reminiscent of the old English African double rifles. Too much fun!
Dave