Be more specific! Is it locking to the rear with the chamber open after firing the round. Or is it locking up in battery (Slide Closed).
If it is locking to the rear it may be your grip. You may be contacting the slide lock with your thumb when the recoil occurs. Causing upward preasure on it and locking the slide to the rear on occassion? This is not uncommon if the grip is not correct!
The Constitution is not an instrument for the Government to restrain the people. It is an instrument for the people to restrain the Government!
Today, we need a nation of Minutemen, citizens who are not only prepared to take arms, but citizens who regard the preservation of freedom as the basic purpose of their daily life and who are willing to consciously work and sacrifice for that freedom."
-- John F. Kennedy