Re: .17HMR and barrel length...
Yep, Al said, what I said, what You said, and the others said, Barrel length affects velocity, many other variables for accuracy. My point was that shortening the tube will likely not hurt accuracy enough to worry about.
All this aside I talked with AL many years ago when I was putting together my first Contender, I was drooling over his Bullberry 17AH. 20-22" gives those rigs the perfect balance, and optimum velocity.
That is true for most of the 17 calibers.
Varmint Als web page should be required reading for anyone getting into shooting, reloading, or any of a ton of interesting topics. He is a neat old bird with a wealth of information he has shared over the years. I learned a lot of tricks from reading his web pages and e mailing back and forth.
He should write a couple books on his outdoor activities.
I was just able to pick up a Bullberry 17HMR, and a 22WMR barrel for my Contender both 18", couldn't pass them up. I needed another HMR like I needed a hole in the head, but what the hell its a fun little round.