Is There A Big Difference In Sound Between A Diana 56Th .177 Compared to A .22?

[Baby Sherman]

I was just curious to hear from someone who has both calibers if theres much of a difference.
Thank you.

[subscriber]

Mark,

I have a Diana 350 "Magnum" in .177 and .22.  The .177 is much louder, even with pellets heavy enough to stay well subsonic.  I would go further, and state that the .177 is not very backyard friendly.

The simple explanation is that because the bore volume on the .177 is 65% that of the bore volume of the .22, the smaller caliber's muzzle pressure is that much higher when the pellet exits.   

The smaller caliber's pellets have a higher muzzle velocity and make a lot more noise.  Drastically so, as lighter pellets approach the speed of sound.   7 grain pellet easily break 1150 FPS and produce a loud and attention grabbing crack.  Even 8 to 9 grain pellets are "noisy".  10.5+ grain pellets are preferred to make use of the 350's capability in .177.

I could be wrong, but I think the 350 and 56 have similar swept volume and spring, thus similar system energy.  If the 56 also has a shorter barrel than the 350 (the latter needs to use the barrel as a long cocking handle), then not only would the 56 be louder than the 350, the .177 would be louder still.

I don't have a lot of .177 pellets weighing over 10 grains.  I have more .22 pellets in the 14 to 18 grain range, and generally would recommend airguns that deliver over 20 foot.pounds to be in .22 caliber.  Now, the Diana 56 may have other considerations that point to the smaller caliber as good to go.  Hopefully someone with experience can share that here.

Meanwhile, these links point to GTA threads on related topics:
www.google.com/search?q=site%3Agatewaytoairguns.org+Diana+56+.22
www.google.com/search?q=site%3Agatewaytoairguns.org+Diana+56+.177

[subscriber]

More:  https://www.youtube.com/results?search_query=diana+56+TH

[Tater]

Moved to the German gate.

[JungleShooter]

Peter,

very interesting. Please, shine some light on the dark side of this discussion (pun & PCP fully intended).


So, here you compared springers, that have similarly sized power sources, a similar spring/ piston — though the MV and ME are different due to the different caliber/ surface on which the air can excert force.


🔸 But what would you think is the difference between PCP's of different caliber?

Let me draw up some concrete parameters:
▪ Comparison a .22cal vs. a .25cal

▪ Barrel length: 600mm both▪ Typical shroud (what we find on most PCPs nowadays)
▪ Tune: regulated, with MV 5% below the max. (the "knee")

▪ MV = 900fps for both
▪ Projectile: 15.89gr (for .22) vs. 25.39gr (for .25)  [mid-weight-for-caliber] 
▪ Power = 28.6FPE (.22) vs. 44.7FPE (.25)

Would you expect a difference in muzzle report? — How much different would you guess that might be?


🔸 Would the comparison between .22 vs. .25 be much different if we increased the pellet weight and power to the following?:
▪ MV = still both 900fps
▪ Pellet weight: 25.39gr (for .22) vs. 33.95gr (for .25)  [heavy-for-caliber]
▪ Power: 44.7 (.22) vs. 61.1FPE (.25)


This is not an academic subject to me, I really am considering this!


(And this here is not yet the question I was going to post a while ago... — you got me into a different ballistic rabbit hole!! 😄 Thanks!! 👍🏼😄) 

Matthias

[subscriber]

Matthias,

To make a more direct comparison to what is essentially a 20 FPE powerplant, with a .177 or a .22 barrel attached to it, your PCP question would be this:

When comparing a .22 and .25 PCPs with the same barrel length, shooting at the same 29 FPE, would the smaller caliber be louder?  The answer is yes, for the same reasons as for the above springers.

What I did not mention is that larger calibers are usually more efficient, so the larger caliber typically will produce more power.  Not in proportion to the larger bore volume (unless perhaps for a pistol, or short barrel carbine), but significant none the less.  My unmodified .177 and .22 HW 50 and HW95 show the larger caliber produce about 20% more FPE, despite the barrel volume being 50% larger.  This is mostly due to to break barrel springer being given a "longer than necessary" barrel, because the barrel is the cocking lever. 

Pellet friction is more for the larger caliber by the ratio of the circumferences (assuming similar interference between pellet and bore).   But, driving area for the air to push on is proportional to the square of the diameter; suggesting larger caliber pellet friction should not dominate the equation.

Back to you PCP questions:
Your situation starts with different FPE by caliber, proportional to pellet masses.   The ratio of bore areas (thus expansion volume) for  a .25 compared to a .22 is 1.29:1 or 29% more.   

The ratio of pellet masses are:
25.4 / 15.9 = 1.6 or 60% more for the .25
34 / 25.4 = 1.34 or 34% more for the .25

Other than pointing to the higher sectional density (and thus BC) of the .25 pellets, the fact that the mass ratio of the pellets is larger than the bore area (and volume) ratio means that the .25 is "working much harder" to achieve those energy levels.  For this to be possible, the average air pressure down the barrel has to be significantly higher for the .25.   

Assuming the regulator or starting pressure is the same, the way to increase the average pressure is to increase valve dwell for the .25 - in both pellet weight instances.  More so, for the lighter pellet combination, compared to the .22, because the ratio of pellet masses is a full 60% higher for the .25 in that instance.

The result is that the muzzle pressure of of the .25 will be significantly higher than the .22.  The ratio of loudness would be greater for the lighter pellets, because the .25 pellet is so much heavier than the ratio of bore areas and volumes.  A similar muzzle pressure rise would occur, if you set the reg pressure higher, although that would produce the required average pressure at a lower muzzle pressure - so, paradoxically, not as loud as with a lower reg or starting pressure.

A higher muzzle pressure, combined with greater air volume at that pressure will make the .25 much louder than the .22.  If they are equally shrouded / and / or suppressed, the .25 will make the shroud and / or suppressor volume work much harder.  So, in any event, the .25 will be louder; unless you detuned the .25 closer to .22 power levels.   

If you detuned the .25 down to 29% over the .22 power level, then the muzzle pressures would be similar.  That suggests the sharpness of the sounds would be similar at that power level, with "volume" of the sound still being greater for the .25.   If this sounds like a contradiction, compare the muzzle blast of a 12 gauge bird shot load to that of a .22 rimfire pistol.  The .22 pistol produces a sharper sound, but the shotgun is arguably much louder despite a lower muzzle pressure - a larger sound, if you like.

If you shot your hypothetical .22 and .25 air rifles and compared light and heavy pellets of the same caliber, I predict that the heavier pellets will be louder than the lighter ones - because you are working harder to achieve the same velocity.  However, if you kept the tune set for the lighter pellets and shot the heavier pellets, the heavier pellets would reduce the report.    They would also not reach the same 900 FPS, but would almost certainly produce more FPE than the lighter pellets at 900 FPS. 

If you want more specifics calculated answers than this, you should post the question to Bob and Lloyd's Workshop, or the Darkside Gates.

[lefteyeshot]

Pellets less than 10.5grs. out of my .177 350 PC crack going down range. And it is a bear to cock.

[Yogi]

Peter,

very interesting. Please, shine some light on the dark side of this discussion (pun & PCP fully intended).


So, here you compared springers, that have similarly sized power sources, a similar spring/ piston — though the MV and ME are different due to the different caliber/ surface on which the air can excert force.


🔸 But what would you think is the difference between PCP's of different caliber?

Let me draw up some concrete parameters:
▪ Comparison a .22cal vs. a .25cal

▪ Barrel length: 600mm both▪ Typical shroud (what we find on most PCPs nowadays)
▪ Tune: regulated, with MV 5% below the max. (the "knee")

▪ MV = 900fps for both
▪ Projectile: 15.89gr (for .22) vs. 25.39gr (for .25)  [mid-weight-for-caliber] 
▪ Power = 28.6FPE (.22) vs. 44.7FPE (.25)

Would you expect a difference in muzzle report? — How much different would you guess that might be?


🔸 Would the comparison between .22 vs. .25 be much different if we increased the pellet weight and power to the following?:
▪ MV = still both 900fps
▪ Pellet weight: 25.39gr (for .22) vs. 33.95gr (for .25)  [heavy-for-caliber]
▪ Power: 44.7 (.22) vs. 61.1FPE (.25)


This is not an academic subject to me, I really am considering this!


(And this here is not yet the question I was going to post a while ago... — you got me into a different ballistic rabbit hole!! 😄 Thanks!! 👍🏼😄) 

Matthias

What difference does it make???

Put a can on the end and you reduce either to a whisper.  Probably help accuracy too....

-Y

[JungleShooter]

What difference does it make???
Put a can on the end and you reduce either to a whisper.

-Y

🔹Yogi,

Yes, THAT'S the difference. The can. 😄

I don't want to add 8 inches to a bullpup..... 🤣  Remind me, why did I get a short gun in the first place...?! 👍🏼😄

But yes, every shooter and every shooting scenario is different, and of course, you are right, many times a can is just fine.



🔸 Peter,

I need to digest your post. I'll get back to you soon. Thank you so much for your detailed reply!! 😊

Matthias

[subscriber]

Yogi;  Is a "whisper" above or below "mouse fart"? 

Sure, if you put a large enough can on it, the noise objection may become moot.  How large is too large, depends on the individual; and how many click of elevation you have left to overcome muzzle droop. 


Matthias, are you sure that your sound level expectations are not violating the laws of physics?  That said, if you can accept a lower shot count, set your reg pressure to max and reduce the valve dwell to achieve your desired velocity.  That gets you the required average pressure, at a much lower muzzle pressure.  In effect, you are then shooting a hot-rodded pistol that uses perhaps two thirds of the (rifle) barrel length as a suppressor expansion volume. 

The above effect is seen when you shoot a non-regulated PCP, starting above the air tank pressure that produces peak velocity at a given hammer strike.  Then keep shooting it a shot string so the velocity rises and falls back to what it was on the first high pressure shot.  You will notice that the high pressure shot sound like a muted snap, while the low pressure shot sounds like a louder open muzzled bark of much longer duration.  This, despite them producing the same pellet velocity.    This effect becomes even more obvious, if you reduce the hammer strike, then shoot a long string.  Then the velocity at high pressure end can be surprisingly low.  Zero even, if you create the condition known as "valve lock".

To further illustrate the point; if you need an average pressure of 1000 PSI to produce your velocity goal, and the air tank is at only just above 1000 PSI, then the valve has to stay open until the pellet leaves the muzzle (tank pressure drops from the shot).  That means the muzzle pressure would be close to 1000 PSI - very loud.  If you produce the same average pressure by taking a small gulp of 3000 PSI air, the air can be "over expanded" to average 1000 PSI.   Without doing the math, that would result in a muzzle pressure of perhaps 333 PSI.  It depends on the barrel length obviously.

[subscriber]

🔸 Peter,

I need to digest your post. I'll get back to you soon. Thank you so much for your detailed reply!! 😊

Matthias,

I suggest you ask your PCP questions in the PCP Gate.  While I have slept in a Holliday Inn Express, I am not a PCP expert.  They abound on the Darkside.  Start a thread there, and post just a link to that new thread, here.  Else what we a doing is not just a thread highjack; it is a gate highjack.


Holiday Inn Express reference for non-US residents:

[Bayman]

Peter,

very interesting. Please, shine some light on the dark side of this discussion (pun & PCP fully intended).


So, here you compared springers, that have similarly sized power sources, a similar spring/ piston — though the MV and ME are different due to the different caliber/ surface on which the air can excert force.


🔸 But what would you think is the difference between PCP's of different caliber?

Let me draw up some concrete parameters:
▪ Comparison a .22cal vs. a .25cal

▪ Barrel length: 600mm both▪ Typical shroud (what we find on most PCPs nowadays)
▪ Tune: regulated, with MV 5% below the max. (the "knee")

▪ MV = 900fps for both
▪ Projectile: 15.89gr (for .22) vs. 25.39gr (for .25)  [mid-weight-for-caliber] 
▪ Power = 28.6FPE (.22) vs. 44.7FPE (.25)

Would you expect a difference in muzzle report? — How much different would you guess that might be?


🔸 Would the comparison between .22 vs. .25 be much different if we increased the pellet weight and power to the following?:
▪ MV = still both 900fps
▪ Pellet weight: 25.39gr (for .22) vs. 33.95gr (for .25)  [heavy-for-caliber]
▪ Power: 44.7 (.22) vs. 61.1FPE (.25)


This is not an academic subject to me, I really am considering this!


(And this here is not yet the question I was going to post a while ago... — you got me into a different ballistic rabbit hole!! 😄 Thanks!! 👍🏼😄) 

Matthias

This is hijacking th OP's thread. This isn't related to the OP's question. You should enjoy a conversation with Peter directly as I often have or start your own thread with your questions.

[Yogi]

What difference does it make???
Put a can on the end and you reduce either to a whisper.

-Y

🔹Yogi,

Yes, THAT'S the difference. The can. 😄

I don't want to add 8 inches to a bullpup..... 🤣  Remind me, why did I get a short gun in the first place...?! 👍🏼😄

But yes, every shooter and every shooting scenario is different, and of course, you are right, many times a can is just fine.



🔸 Peter,

I need to digest your post. I'll get back to you soon. Thank you so much for your detailed reply!! 😊

Matthias

So get a 4 inch can.  What has this got to do with the OP's question about springers?   Springers and PCP's generate "the noise" completely differently.

-Y

[Yogi]

Peter,

very interesting. Please, shine some light on the dark side of this discussion (pun & PCP fully intended).


So, here you compared springers, that have similarly sized power sources, a similar spring/ piston — though the MV and ME are different due to the different caliber/ surface on which the air can excert force.


🔸 But what would you think is the difference between PCP's of different caliber?

Let me draw up some concrete parameters:
▪ Comparison a .22cal vs. a .25cal

▪ Barrel length: 600mm both▪ Typical shroud (what we find on most PCPs nowadays)
▪ Tune: regulated, with MV 5% below the max. (the "knee")

▪ MV = 900fps for both
▪ Projectile: 15.89gr (for .22) vs. 25.39gr (for .25)  [mid-weight-for-caliber] 
▪ Power = 28.6FPE (.22) vs. 44.7FPE (.25)

Would you expect a difference in muzzle report? — How much different would you guess that might be?


🔸 Would the comparison between .22 vs. .25 be much different if we increased the pellet weight and power to the following?:
▪ MV = still both 900fps
▪ Pellet weight: 25.39gr (for .22) vs. 33.95gr (for .25)  [heavy-for-caliber]
▪ Power: 44.7 (.22) vs. 61.1FPE (.25)


This is not an academic subject to me, I really am considering this!


(And this here is not yet the question I was going to post a while ago... — you got me into a different ballistic rabbit hole!! 😄 Thanks!! 👍🏼😄) 

Matthias

This is hijacking th OP's thread. This isn't related to the OP's question. You should enjoy a conversation with Peter directly as I often have or start your own thread with your questions.

+1, +2

-Y

[JungleShooter]

Mark,

Please, forgive me for hijacking your thread. 😞

And to the rest of the posters — I'm sorry for also hijacking your springer gate for a PCP question 😬 — I usually don't do this. Big brain fart. Please, do open the virtual windows.


Hope you all have a good day shooting (or typing). 😊

Matthias



PS:  The discussion is now located here:
https://www.gatewaytoairguns.org/GTA/index.php?topic=202259

[Baby Sherman]

No worries,  you can hijack my thread anytime,  lol.
I was surprised that a Diana .177 springer is louder than the .22.
Good thing I asked.
With that said, I am leaning on the HW97 (blackline stl) for my first springer because I'm told the 56TH has been discontinued as well as a particular part needed when rebuilding, some washer I believe.

[Denby95]

If you would like a 56, they're for sale at AOA right now. Otherwise the Diana 54 and Diana 54 Pro still exist (just different stocks to the 56, same mechanism)

https://www.airgunsofarizona.com/spring-piston/diana-model-56-target-hunter/

I own a 54, and shooting it is unlike shooting any other springer, it really does work wonders for the recoil absorption. That being said, it is a very heavy gun and shooting it off hand tires pretty quickly, much more of a bench rest shooter.