Pellet Power .177 v .22

[London177]

Hello everyone,
Here's something I find surprising.
When I plink at tin cans in my garden with my two QB78's I find that I get nice clean entry and exit holes with my .177 and the can often remains standing. However, my .22 often smacks a whole in the can but that's it. No exit hole. The can then usually topples over or flies around.
How is this so?
I know .22 packs more energy in its pellet than a .177 hence the can flying through the air but why does it not exit the other side of the can?
For the record I was shooting with both rifles that had new CO2 cartridges, temperature was around 70F and the pellets were cheapish domed type. Range is about 20yds. The cans vary from beer cans to tuna fish cans and the odd aerosol can.
regards,
Alan  

[ribbonstone]

Figure out the square inch area vs. the energy delivered.  .177 is puting more energy per square inch, even though it has less total energy.

[ribbonstone]

At work:

Figured some out on the way....just doodling on a scrap of paper and might have dropped a decimal point here or there....figure with 8 foot popunds of energy, the .177 is getting something like 320 foot pounds per square inch while the .22 (same 8 foot pounds) is getting 210.

This kind of stuff is only useful for figuring penetration on sheets of hard material (like tin cans), doesn't predict meat-impact.

BTW: if you were to glue the tin cans down, the .22 might come out the other side...uses up a good bit of energy moving the can between hitting the first side and the second.

[London177]

Hi ribbonstone,
Thanks for the physics
It's clear to me now. I will use a bit of silicon to glue them to a plank of wood and see what happens with the .22.
I think a lot of folks will go for .22 over the .177 but as you demonstrated sometimes a .177 has the edge
regards,
Alan