I purchased my first Glock earlier this year. Prior to my purchase, I had shot a Glock 3 times. The first time, I shot a 17L, and I really didn't like the feel of the pistol. Two years ago, when I worked my first GSSF match, I was lent a G34 so I could try the match. Last year, while working my club's GSSF match, I was lent a G17Gen4 so I could shoot the match. I didn't like the feel of the finger grooves, but I was able to take the prize for the high score by a handicapped shooter. When I purchased my Glock, I went with a G17Gen5 MOS for maximum match utility.

My suggestions:
1) if you are contemplating purchasing a new Glock, join the GSSF first so you can take advantage of the member discount. The MSRP for a G17Gen5 MOS is over $600, with the member discount it cost about $480.
2) if you reload, Glocks seem to respond well to coated bullets.
3) one way you can become more proficient with your Glock is to join the GSSF and participate in their matches. You don't have to be in the top places to win, they have special category awards and random awards that can vary from pistols to cash to memberships.

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Judge control not gun control!