An explantion of a backfire (Or Breach explosion)
A normal round of ammunition is made up of 2 main bodies
1) The bullet (which is the damage doing projectile bit)
and the
2) Main body (lets call this the cartridge side) which holds the explosive charge
a backfire occurs when the bullet jams in the barrel or chamber of the weapon
Normally when the cartidge that houses the Bullet explodes, the force projects the bullet out of the barrel to its target
Some of this explosive energy (expansion of gases) is also used to force the working mechanism back, thus reloading the next round
If the round jams, then there is insufficient release points for this explosive gas pressure.
The working parts are still normally forced back, but with too much force and the resulting "Increased" pressure release which occurs is called a backfire or breach explosion
This can injure the weapon firer to some extent
Anything from a burn mark, to losing a finger or being blinded, dependant on the weapon being fired.
To reduce this from happening, soldiers periodically clean their weapon, oiling the working parts and pulling something through the barrel. The dirtier the working conditions, the more frequent the cleaning
If a misfire or blockage does occur, then they carry out "Blockage" drills, this is specific to the weapon and dependant on the severity of the blockage.
Could be abything from a simple reload to a full field strip down of the weapon
Most blockages are detected before a soldier would attempt to refire his weapon, infact most blockages on the weapons i have fired stop any additional loading into the breach anyway
As for increased recoil, i couldnt answer that, as i have never suffered a breach explosion, however its doubtful that an increased recoil would be detected by the firer