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PostPosted: Tue Sep 27, 2016 4:14 pm 
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I recently put a .22 Phantom 500 barrel on my Nitro Venom .177 and the gun in now 2-1/2 inches shorter than the original Nitro Venom .22....its sort of a carbine now and as a side benefit I have picked up 20 -25 fps with the shorter barrel.
Crosman Premiers 14.3@705 fps
Pyramid Air's Rick Uetsler chronies the original Nitro Venom .22. @680 fps with the same pellet...so that's cool....its shooting faster.

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PostPosted: Tue Sep 27, 2016 8:05 pm 
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You can't compare fps with the PA vid. When they test a gun it's not about that model, it's that individual gun. The next one off the assy line can be very different. I've had oem generic Crosman guns in 22 shoot 14.35gr pellets anywhere from 550 to 770 out of the box (after dieseling). The guns are the same mechanically, just different trim to make a "new" model. I suppose a normal avg for your gun (excluding bad nitros) is likely 700? Then from there I'd say most most all of them are +-50. What causes one to be 650 and another 750 can be all kinds of stuff, including the barrel itself. A different barrel can have quite the effect, and strangely it can even have a different effect on different guns. I've swapped barrels around between guns and found that some barrels suck period, some seem ok on one gun but suck on another, but the one thing that seemed consistent is barrels were not consistent. For example if I have a gun giving me issues I'll put a known good barrel on it to see if the orig barrel was the problem. If you have power loss due to a tight and/or rough barrel then sanding can help or fix that. If too lose then replacement is the only fix.
Between power and accuracy issues I like to have spare barrels on hand. I probably have six sitting here right now, and they why is because sooo many are bad that even buying two or thee spares with one gun is no guarantee you'll have a good one.
If you're near sea level then getting 750 should be pretty easy with some kinda (imo) basic mods. I cudda swore I sent you the info on that stuff but maybe not? The mods not only make more power but make it a better shooter in every way.


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PostPosted: Tue Sep 27, 2016 9:23 pm 
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Chevota wrote:
You can't compare fps with the PA vid. When they test a gun it's not about that model, it's that individual gun. The next one off the assy line can be very different. I've had oem generic Crosman guns in 22 shoot 14.35gr pellets anywhere from 550 to 770 out of the box (after dieseling). The guns are the same mechanically, just different trim to make a "new" model. I suppose a normal avg for your gun (excluding bad nitros) is likely 700? Then from there I'd say most most all of them are +-50. What causes one to be 650 and another 750 can be all kinds of stuff, including the barrel itself. A different barrel can have quite the effect, and strangely it can even have a different effect on different guns. I've swapped barrels around between guns and found that some barrels suck period, some seem ok on one gun but suck on another, but the one thing that seemed consistent is barrels were not consistent. For example if I have a gun giving me issues I'll put a known good barrel on it to see if the orig barrel was the problem. If you have power loss due to a tight and/or rough barrel then sanding can help or fix that. If too lose then replacement is the only fix.
Between power and accuracy issues I like to have spare barrels on hand. I probably have six sitting here right now, and they why is because sooo many are bad that even buying two or thee spares with one gun is no guarantee you'll have a good one.
If you're near sea level then getting 750 should be pretty easy with some kinda (imo) basic mods. I cudda swore I sent you the info on that stuff but maybe not? The mods not only make more power but make it a better shooter in every way.


I agree....guns of the same model can vary in performance...due to minute differences in their construction.....what I am saying is MY gun shoots faster with a shorter barrel…faster than the stock untuned ones I see chronied on youtube...If I add 2 inches to the barrel it will shoot less fps.....NOT the same...NOT more...but LESS.......DIG??????
What manner of physics would speed up a pellet that is subject to MORE friction while travelling up the barrel.?After a certain point...a pellet receives ALL the boost its going to get from compression....then it starts to slow down......somewhere in the middle or near the end of the barrel.....…keep reading....keep experimenting......keep learning....you'll catch on....

P.S...this from Airgun Academy...Cardew determined optimum spring gun barrel length
A spring gun gets all of its “push” in the first few inches of the barrel. Gerald Cardew pointed out in The Airgun from Trigger to Target that only the first six inches of the barrel is needed for a spring gun to achieve maximum velocity. His experiments were conducted in the mid-1970s. Although technology has advanced since then, today’s spring-piston guns probably don’t use more than the first 10 inches of barrel for top velocity
http://www.pyramydair.com/blog/2005/04/ ... important/

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PostPosted: Tue Sep 27, 2016 10:32 pm 
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Seriously disappointed to see an attitude from you, again....

The only true way to compare is to take your gun with one barrel, measure fps, then cut that barrel down and measure again. Comparing two guns, or two diff barrels on your gun nullifies the test. What if the gun PA happened to test did 750? Would you then state you lost a ton of fps with that 2.5"?
To be honest, even the same barrel on the same gun can be misleading depending on defects, which are often significant with chinese guns. If you have a tight spot in the barrel early on (very common) then it will bleed off air making it appear a shorter barrel is better, so really you'd need a known good barrel. So the guns and barrels are different, and the power and quality of each is unknown. I'd say a guess would be more accurate.
I suppose I can cut a 22 barrel down to see how it reacts, but I can tell you that 1" from a 177 barrel on that gun will cause a drop, so a 177 on that type gun needs at least 18.5", but possibly more. It could be it peaks at 25, I don't know since I only have 18.5 to play with. A 22 doesn't need as much barrel but what length is ideal in that gun I can only guess, especially since I don't know for sure what a 177 needs. My guess is 18.5 is probably close enough to max power/length, if so then maybe 15" or even less is ideal for 22.
The Cardew book is outdated, measurements like that do not apply to your gun. If you'd like to try you can cut one of yours down to 6", or a more modern 10 as you suggest and see what happens. I mean if you're certain about that Cardew data and believe I'm full of it.


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PostPosted: Tue Sep 27, 2016 10:40 pm 
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MyCrosman wrote:
I recently put a .22 Phantom 500 barrel on my Nitro Venom .177 and the gun in now 2-1/2 inches shorter than the original Nitro Venom .22....its sort of a carbine now and as a side benefit I have picked up 20 -25 fps with the shorter barrel.
Crosman Premiers 14.3@705 fps
Pyramid Air's Rick Uetsler chronies the original Nitro Venom .22. @680 fps with the same pellet...so that's cool....its shooting faster.

I have found 4 youtube videos so far of guns in the same power category, shooting the same pellet, that shoot less fps than yours so you're doing alright.
It could well be the shorter barrel achieiving a slightly higher fps.


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PostPosted: Tue Sep 27, 2016 10:56 pm 
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Chevota wrote:
Seriously disappointed to see an attitude from you, again....

The only true way to compare is to take your gun with one barrel, measure fps, then cut that barrel down and measure again. Comparing two guns, or two diff barrels on your gun nullifies the test. What if the gun PA happened to test did 750? Would you then state you lost a ton of fps with that 2.5"?
To be honest, even the same barrel on the same gun can be misleading depending on defects, which are often significant with chinese guns. If you have a tight spot in the barrel early on (very common) then it will bleed off air making it appear a shorter barrel is better, so really you'd need a known good barrel. So the guns and barrels are different, and the power and quality of each is unknown. I'd say a guess would be more accurate.
I suppose I can cut a 22 barrel down to see how it reacts, but I can tell you that 1" from a 177 barrel on that gun will cause a drop, so a 177 on that type gun needs at least 18.5", but possibly more. It could be it peaks at 25, I don't know since I only have 18.5 to play with. A 22 doesn't need as much barrel but what length is ideal in that gun I can only guess, especially since I don't know for sure what a 177 needs. My guess is 18.5 is probably close enough to max power/length, if so then maybe 15" or even less is ideal for 22.
The Cardew book is outdated, measurements like that do not apply to your gun. If you'd like to try you can cut one of yours down to 6", or a more modern 10 as you suggest and see what happens. I mean if you're certain about that Cardew data and believe I'm full of it.


Its shooting faster....its physics...that stays the same...friction reduces speed....I DO have enough guns that I could sacrifice one for THAT test but I already have it right....Longer rifle barrels slow down a pellet..….long barrels on springer air guns are for looks and ease of cranking them...not for maximum fps.Whose going to buy a gun with a short barrel that is difficult to cock...just for a few more fps.Very few people....manufacturers know this...You should too.

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PostPosted: Wed Sep 28, 2016 12:51 am 
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I don't know what to say because important unknown factors completely nullify the test but you're ignoring that.
In a post a couple months ago I said I'd do another barrel length test if people antagonized me enough with that old Cardew crap, so I don't know if you're actually serious or acting on my comment....


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PostPosted: Wed Sep 28, 2016 6:38 am 
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Chevota wrote:
I don't know what to say because important unknown factors completely nullify the test but you're ignoring that.
In a post a couple months ago I said I'd do another barrel length test if people antagonized me enough with that old Cardew crap, so I don't know if you're actually serious or acting on my comment....


Well maybe you should do a barrel length test....there's probably more than a little interest among readers.I see a few posts wondering what length of barrel would be best...especially with 2240 and 1322/77 owners.

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PostPosted: Wed Sep 28, 2016 10:01 am 
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I wonder what would be the spread of FPS if you take 100 stock Nitro Venom .22 and crony them all. I would wager there would be at least a 25 FPS difference between the fastest and the slowest of the group.

The only conclusion when you compare your Nitro Venom .177 with the Phantom .22 barrel with the PA test Nitro Venom .22, is that yours tested faster. You can't conclude why it is faster, since there are dozens if not more uncontrolled variables that affects the measured FPS. Heck, you can't even conclude 100% that yours is faster because you didn't test under identical conditions such as temperature, altitude, placement of the chrony, and the chrony themselves may measure differently (Ie. The accuracy is +/- a certain FPS). When was the last time you calibrated your Chrony or PA did theirs?


Last edited by Pokerdogg on Wed Sep 28, 2016 10:25 am, edited 1 time in total.

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PostPosted: Wed Sep 28, 2016 10:14 am 
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Pokerdogg wrote:
I wonder what would be the spread of FPS if you take 100 stock Nitro Venom .22 and crony them all. I would wager there would be at least a 25 FPS difference between the fastest and the slowest of the group.

The only conclusion when you compare your Nitro Venom .177 with the Phantom .22 barrel with the PA test Nitro Venom .22, is that yours tested faster. You can't conclude why it is faster, since there are dozens if not more uncontrolled variables that affects the measured FPS. Heck, you can't even conclude that yours is faster because you didn't test under identical conditions such as temperature, altitude, placement of the chrony, and the chrony themselves may measure differently (Ie. The accuracy is +/- a certain FPS).

I agree with they're being many variables....but more friction through a longer barrel will slow down a pellet...not by much but it will slow ....Is more friction going to speed up the pellet?

Actually if you reread my initial post I wasn't comparing a .177 to a .22.....I was comparing the .22 barrel I installed on my .177 powerplant and then comparing the results to factory untuned .22 calibre air rifles( with original longer barrels) I see being chronied on you tube.....such as the Optimus .the Titan...the RWS 34...etc.

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PostPosted: Wed Sep 28, 2016 10:29 am 
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When you are talking springers, it is quite common for shortening a barrel not to lose velocity, and sometimes cause an increase.... That is why some factory springers have barrels less than a foot long.... Springer get their power from the adiabatic compression of the air in the spring chamber during the shot cycle.... Generally, more powerful springers will require a longer barrel to take advantage of the extra air volume being compressed by the spring.... All springers will have an "optimum" barrel length, beyond which the pellet will slow.... This is typically between 8-16"....

When you are dealing with pneumatic rifles (pumpers and PCPs, even CO2), generally the reverse is true, longer barrels give more velocity.... This is because you are dealing with expanding previously compressed air, and a longer barrel allows more expansion and hence more power to be extracted from the air.... far exceeding the extra friction from the additional barrel length.... While these rifles will also have an optimum barrel length, that may be several feet in the case of a high powered PCP....

Bob

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PostPosted: Wed Sep 28, 2016 10:33 am 
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MyCrosman wrote:
Pokerdogg wrote:
I wonder what would be the spread of FPS if you take 100 stock Nitro Venom .22 and crony them all. I would wager there would be at least a 25 FPS difference between the fastest and the slowest of the group.

The only conclusion when you compare your Nitro Venom .177 with the Phantom .22 barrel with the PA test Nitro Venom .22, is that yours tested faster. You can't conclude why it is faster, since there are dozens if not more uncontrolled variables that affects the measured FPS. Heck, you can't even conclude that yours is faster because you didn't test under identical conditions such as temperature, altitude, placement of the chrony, and the chrony themselves may measure differently (Ie. The accuracy is +/- a certain FPS).

I agree with they're being many variables....but more friction through a longer barrel will slow down a pellet...not by much but it will slow ....Is more friction going to speed up the pellet?

Actually if you reread my initial post I wasn't comparing a .177 to a .22.....I was comparing the .22 barrel I installed on my .177 powerplant and then comparing the results to factory untuned .22 calibre air rifles( with original longer barrels) I see being chronied on you tube.....such as the Optimus .the Titan...the RWS 34...etc.


I realized you put a .22 barrel on your .177 Nitro Venom, I meant to say that in my post.

I understand what you are saying in terms of friction slowing down a pellet. What we don't know, and cannot conclude from your observation, is at what barrel length that peak speed occurs. We can probably agree a 1/2 barrel is not going to produce top speed based on what we know, so clearly shorter isn't necessarily better in terms of top speed.


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PostPosted: Wed Sep 28, 2016 10:42 am 
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Pokerdogg wrote:
MyCrosman wrote:
Pokerdogg wrote:
I wonder what would be the spread of FPS if you take 100 stock Nitro Venom .22 and crony them all. I would wager there would be at least a 25 FPS difference between the fastest and the slowest of the group.

The only conclusion when you compare your Nitro Venom .177 with the Phantom .22 barrel with the PA test Nitro Venom .22, is that yours tested faster. You can't conclude why it is faster, since there are dozens if not more uncontrolled variables that affects the measured FPS. Heck, you can't even conclude that yours is faster because you didn't test under identical conditions such as temperature, altitude, placement of the chrony, and the chrony themselves may measure differently (Ie. The accuracy is +/- a certain FPS).

I agree with they're being many variables....but more friction through a longer barrel will slow down a pellet...not by much but it will slow ....Is more friction going to speed up the pellet?

Actually if you reread my initial post I wasn't comparing a .177 to a .22.....I was comparing the .22 barrel I installed on my .177 powerplant and then comparing the results to factory untuned .22 calibre air rifles( with original longer barrels) I see being chronied on you tube.....such as the Optimus .the Titan...the RWS 34...etc.


I realized you put a .22 barrel on your .177 Nitro Venom, I meant to say that in my post.

I understand what you are saying in terms of friction slowing down a pellet. What we don't know, and cannot conclude from your observation, is at what barrel length that peak speed occurs. We can probably agree a 1/2 barrel is not going to produce top speed based on what we know, so clearly shorter isn't necessarily better in terms of top speed.



I agree with rsterne....all other things being equal...a low or mid powered springer will benefit from a shorter...but not TOO much shorter barrel and a high powered gun requires a longer barrel to fully utilize the charge behind the pellet.]

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PostPosted: Fri Sep 30, 2016 11:34 pm 
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Do you have an ideal barrel length in mind for 177 and 22 on a gun like yours? I of course still think 18.5" is really too short for a B18 in 177. The gun the Cardews used to claim 6" or whatever they said was probably making 5ftlbs or less, if so then wouldn't a 15+ftlb gun need 18+"? This is probably why your 500fps barrel is shorter, it was meant for a weak gun. Imo it's no doubt too long for a 500fps 22 but it may be ideal for yours. So to be clear I'm not saying that barrel in 22 is too short on your gun, I'm saying that your comparo to the PA test is pointless. An actual test would be to cut your barrel or ideally get an 18.5" barrel and cut it in increments like I have planned. If you believe the short barrel theory then you have plenty of room to cut your 16" barrel which would net you more power and accuracy. Like just 1-2" to see what happens. I don't know what it'll do, I think at your power level 16" is longer than needed, but not sure if you'll gain since I don't have as much belief in the friction thing. I think the pellet will cruize past the minimum peak power length for some distance before actually losing speed. how much distance I don't know, maybe several inches? I also don't trust the shorter = better accuracy thing for two reasons, one is harmonics change so it may be for the worse, and two is chinese barrels are sketchy so no telling what happens when you cut it. I mean odds are it should be more accurate, just saying I wouldn't put $ on it.
I'd send you a barrel to hack up if you paid for shipping, but my guess is that shipping alone is more than a new one.

The testing I'd do would only be valid for a springer, and more specifically for a B18 in the same caliber, and to be even more anal, only one making the same power with the same spring. So while the data will likely be close enough for other full power B18 guns in the same caliber, there is no way it'll apply to pneumatic or CO2 guns. It may be close by accident but the guns are totally different in power and how they work.

Pokerdogg: The spread would be 100+fps as I mentioned earlier, if you excluded the bad ones shooting <650.


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PostPosted: Sat Oct 01, 2016 7:47 am 
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Chevota wrote:
Do you have an ideal barrel length in mind for 177 and 22 on a gun like yours? I of course still think 18.5" is really too short for a B18 in 177. The gun the Cardews used to claim 6" or whatever they said was probably making 5ftlbs or less, if so then wouldn't a 15+ftlb gun need 18+"? This is probably why your 500fps barrel is shorter, it was meant for a weak gun. Imo it's no doubt too long for a 500fps 22 but it may be ideal for yours. So to be clear I'm not saying that barrel in 22 is too short on your gun, I'm saying that your comparo to the PA test is pointless. An actual test would be to cut your barrel or ideally get an 18.5" barrel and cut it in increments like I have planned. If you believe the short barrel theory then you have plenty of room to cut your 16" barrel which would net you more power and accuracy. Like just 1-2" to see what happens. I don't know what it'll do, I think at your power level 16" is longer than needed, but not sure if you'll gain since I don't have as much belief in the friction thing. I think the pellet will cruize past the minimum peak power length for some distance before actually losing speed. how much distance I don't know, maybe several inches? I also don't trust the shorter = better accuracy thing for two reasons, one is harmonics change so it may be for the worse, and two is chinese barrels are sketchy so no telling what happens when you cut it. I mean odds are it should be more accurate, just saying I wouldn't put $ on it.
I'd send you a barrel to hack up if you paid for shipping, but my guess is that shipping alone is more than a new one.

The testing I'd do would only be valid for a springer, and more specifically for a B18 in the same caliber, and to be even more anal, only one making the same power with the same spring. So while the data will likely be close enough for other full power B18 guns in the same caliber, there is no way it'll apply to pneumatic or CO2 guns. It may be close by accident but the guns are totally different in power and how they work.

Pokerdogg: The spread would be 100+fps as I mentioned earlier, if you excluded the bad ones shooting <650.


Maybe I HAVE lost fps by not buying a longer stock barrel for my gun.My gun shoots a little faster than the other stock .22s I mentioned above...but maybe it would shoot even FASTER....However....its not ALL about a few extra fps anyway.I like the carbine- like look of this gun which wasn't intentional...I had an extra .22 barrel so I put it on and hey it looks cool to me...So I'll take the " new look" over a few more fps.If I happen upon a full length .22 barrel..…Ill test it out but for now I like the way it is.......STILL...I have to admit...you got me thinking......maybe I'm missing out on a LOT more fps.....hmmmm.

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