Maine coon cat?

i have a cat that looks like a maine coon but im not sure if he is or not-he is only 6 months old & is already 10lbs-he is twice the size of his sisters i have pictures of him & looked at pictures of maine coon cats ---im just woundering if he is or is not

I seriously doubt that you have a purebred cat. there are many DLH cats that are roaming the streets that do not have a pedigree.

I attend cats shows regularly so if you want to include a picture I can definitely tell you yes or no

I don't know how you would tell. I have two cats from a maine coon's litter. One looks and acts like a maine coon, the other does not. The one that looks like a maine coon makes a lot of weird little noises, kinda like R2-D2. Listen to your cat - does he make little squeeks and buzz noises?

I did some research and found this:
Everything about the Maine Coon points to its adaptation to a harsh climate. Its glossy coat, heavy and water-resistant, is like that of no other breed, and must be felt to be appreciated. It is longer on the ruff, stomach and britches to protect against wet and snow, and shorter on the back and neck to guard against tangling in the underbrush. The coat falls smoothly, and is almost maintenance-free: a weekly combing is all that is usually required to keep it in top condition. The long, bushy tail which the cat wraps around himself when he curls up to sleep can protect him from cold winters. His ears are more heavily furred (both inside and on the tips) than many breeds for protection from the cold, and have a large range of movement. Big, round, tufted feet serve as 'snow shoes.' Their large eyes and ears are also survival traits, serving as they do increase sight and hearing. The relatively long, square muzzle facilitates grasping prey and lapping water from streams and puddles.

Although the Yankee myth of 30-pound cats is just that, a myth (unless the cat is grossly overweight!), these are indeed tall, muscular, big-boned cats; males commonly reach 13 to 18 pounds, with females normally weighing about 9 to 12 pounds. Add to that two or three inches of winter coat, and people will swear that they're looking at one big cat.

Maine Coons develop slowly, and don't achieve their full size until they are three to five years old. Their dispositions remain kittenish throughout their lives; they are big, gentle, good-natured goofs. Even their voices set them apart from other cats; they have a distinctive, chirping trill which they use for everything from courting to cajoling their people into playing with them. (Maine Coons love to play, and many will joyfully retrieve small items.) They rarely meow, and when they do, that soft, tiny voice doesn't fit their size!

I would be willing to bet that your vet can definitely tell you yes or no.