If clean the inside of the barrel of my gun with a stiff wire brush, will that change the rifling?

 A brass wire brush of the correct size for the bore will not change the rifling cut into the hardened steel barrel, but over time it will alter the ballistic signature used to distinguish between bullets fired from guns of the same make and model via forensic examination. 

Any significant abrasion will alter the signature, such as firing 4 boxes of ammo (200 rounds) at the range. 

This is a gradual process that occurs due to normal wear. If a criminal needed to drastically alter the signature immediately, a rat tail file would be run through the bore, and other parts would need to be altered to change the markings on ejected casings.

A brass brush is typically only run through the bore ten times per cleaning session, which will produce far less friction than repeatedly firing it. It would require about ten cleanings to make a noticable difference. It is unlikely this would effect accuracy in anything other than a competition firearm. Nylon brushes produce less friction than brass and are just as good for regular cleanings with domestic commercial ammo. Eastern European, Soviet, Chinese, Egyptian ammo is very dirty due to the type of gunpowder used and would require a brass brush. Very dirty guns encrusted with carbon would require a brass brush and harsh solvents. A nylon brush is best if you want to reduce the risk of scratching the bore.

One important thing to remember when cleaning a gun is to ascertain the brush passes all the way through the barrel. If you reverse the direction of the rod while the brush is inside the bore, it can get stuck. If the brush is stuck within the bore, it will require a great deal of force to remove, possibly even breaking the rod which would likely require the attention of a gunsmith.