Why would guns of the same power leave bigger holes?

[redroush00]

My Big cat and ruger both shoot at 930 FPS. At 20 yards the Cats holes in a soup can are larger ina nd out. Whats going on?

[Big_Bill]

In my experience the more powerful air guns in the same caliber make smaller holes, when using the same make and brand pellet.

The faster pellet goes through faster, allowing less time for the pellet expand, and make a bigger hole.

Bill

[michael90t]

hrmmm if they both chrony the same I would have to say that is odd and I dont have a clue as to why that would happen.....does the gun shooting the smaller hole generallyseem more accurate? if so maybe the other gun is keyholing the pellet????only idea I have...

[redroush00]

The Ruger is more accurate but, the Cat is only half inch spreads at 20 yards.

[RedFeather]

Might be the Cat is keyholing or wobbling a little bit. Only thing I can think of.

[Progun]

Well you didn't say so I guess it's implied that you used the same pellet for both guns?. And I can only assume that both rifles were fired from exactly the same distance and exactly the same angle at said soup can.(?) Did you shoot two different soup cans or was only one can used to record shots from both rifles? Could it be that you just don't have enough data to fairly evaluate and draw conclusions. Are you familiar with what is called the "Scientific Method" of having a theory and testing hypothesis? Do more testing with different media (soup cans, paper,etc) and report back.

[LongIslandArcher]

Bore diameter and depth of the rifling grooves.  If the bore diameter of one rifle is slightly larger or smaller than the bore of the other rifle, then the skirts of the pellets will flare out to different sizes.

[djmyers]

Only thing I can add is if the pellets are starting to destabilize out of one and basically tumble where as the other is staying straight. And that could be caused by waht long Island archer was talking about.

[LongIslandArcher]

The pellets wouldn't necessarily destabilize, because 930 fps is still subsonic, so there's no sonic shock wave ahead of the pellet that would cause it to tumble.  Not all barrels have the same diameter - some are bored a little tighter than others.  Think of how a shotgun choke works and that is analogous to what the pellets are doing when they are pushed down barrels bored differently.  A less tight barrel with deeper lands and grooves will make a pellet skirt flare out more than a barrel that has tighter tolerances.

[redroush00]

Same pellet same exact rest. I will say that the pellet is a little less tight than the Ruger.

[tjk]

Interesting quandry. I doubt the pellets are tumbling at that velocity and range, and if so, then you might check the crown of the barrel to ensure there isn't a burr nicking a pellet exiting from the barrel. Shooting into paper is the best test for key-holing. Like Progun stated, you might want to do your testing from a more controlled approach,..... two rifles, to new cans, same count pellets, same distance, etc. I have a sneaking suspicion your rifles aren't shooting at the exact same FPS. As a matter of fact, I would perform each shot in a new test through your chroney and log every shot to keep a record. Try to keep everything the same as much as possible. Controlled testing is the key element for accurate results. Good Luck with your testing!! tjk

[airiscool]

If, the bore size is constant from breach to muzzle, the differance between a pellet fitting "snug"  or "loose"  into a breach, is usually so small an amount, I doubt you could tell the differance just by looking at the hole left by the pellets. Otherwise, to have a big enough size differance in pellets to see that differance after they've left the muzzle, you'd either have to hammer  pellets into the tigher breach, or pellets would fall through the loose breach.

The muzzle end of each gun may hold the answer. Does one gun have a "choked" barrel and the other doesn't ?

As far as stability, there are other factors that can affect Pellet stability besides being near the speed of sound.  As TJK mentioned check the crown for a slight burr.

I'd compare muzzle sizes. Next, check crowns.  If that reveals nothing, then give each barrel a good cleaning and re-shoot at a new can over the chrony.  

Paul.