HOW DO I BUY A GOCK 30 GEN 4 ONLINE THINGS TO KNOW BEFORE YOU BUY

My next G30SF also had precision challenges as well as the WORST cause pull of ANY Glock I've ever owned, And that i could NOT right it applying this set up it doesn't matter what I did and perfectly over 1,000 rounds of endeavoring to fix it and “split in” the gun (which I have NEVER had to do with any Glock prior to possibly).It's lighter and