They are both Excellent Rifles but I personally feel the Gamo has the edge on the Crosman. Both shoot lead pellets at 1000 FPS. Both will shoot the PBA pellets at 1200 FPS. The Gamo has a 38lbs cocking effort while the Crosman has a 31.5lbs cocking effort. The Crosman with scope is a little less expensive than the Gamo with scope. So it this isn't a big deal to you then I would go with the Gamo Big cat. Take a look at: http://www.pyramydair.com/p/gamo-big-cat-1200-air-rifle.shtml http://www.pyramydair.com/p/crosman-quest-1000x-kit.shtml
The Big Cat 1250 fire a .177 caliber pellet. If you are looking for more specific information, I would contact GAMO USE directly and ask them. See the link below
It's usually on the side of the barrel, close to the hinge
First of all it must be legal in the country where you live to make this modification. Second I would contact Gamo and ask them directly for the parts list.
It is a rather large rifle for a 12 year old, but under adult supervision is should be alright.
It depends on the size of the person, But most likely "Yes" he should be able to load it himself with adult supervision.
No, it is designed for pellets not BB's. Any BB will destroy the rifling in the barrel over time.
Get a GR3T trigger for it. It is considered the very best trigger available for Gamo. See the link below
Take a look at the comparison chart (see the link below) I think the Gamo has a slight edge over the Black hawk.
This is like asking is Ford better than Chevy. It all really personal opinion. The Gamo cost a little more but both are rated at 1000 FPS. The XT has a wood stock the Gamo has a synthetic stock. So the choice is yours.
Barrel is a big container to contain liquids.
Yes it is 2 5/8 inches and that is considered a big barrel bat.