What pellets pop the loudest and quietest on game ?

[screwwork]

There’s no absolute silent airgun hunting

For super quiet shooting in the backyard, lower your fps to lower your impact sound. Domed pellets or pointed pellets work the best but then you get pass-through noise into a backstop. Back when I was backyard pesting I would keep one gun tuned super low for this and shooting a .177 at 5/6fpe.

[Back_Roads]

 I should of bought a DB meter when I started my squirrel eradication project, As the population decreased the distances and caliber of airgun increased, now up to .25 and domed pellets are sounding like 2" branches being snapped in half on impact.
 NOE cast pellets have a flat nose and really pop the loudest of anything "domed" I have shot.

[Struckat]

Shooting Hobby 11.7 out of my stock Prod makes a “Zip” sound.
Shooting a chippy makes a pleasing “Zip-Pop”

[only1harry]

The "loudest" pellet I have ever used is the Polymag Predator (hollow-point with the red tip).  Every time I shot something with the Polymag from the Condor .22 or .25 it would make a very loud "crack" when it came in contact with the skull of a squirrel or Groundhog and shattered it.  Same with Starlings - loud crack that was a lot louder than the muffled report, and it echoed through the neighborhood.  If I hit the vitals of a squirrel it would be a loud "thud".  FPE has a lot to do with how loud the impact is too, and obviously I was using very high FPE PCP's with this particular pellet.  I stopped using hollow-points and went back to domed pellets that were a lot less "quiet" by comparison. 

No matter what pellet you use, the velocity or power of your gun will determine how loud or how quiet it will be on impact.

[sonnysan]

With my dB meter, the quietest airgun hunting is about 105dB at the muzzle and at the target (measured both ends from a 16FPE .177 Daystate Regal Classic).