I currently have 14 uppers in the following calibers,22LR,9mm,.223,and 300 Whisper.I was going to build my 300 Whisper but found one on the EE.I have all the parts to build another upper minus the barrel.I am a fan of the .17.I have a 17HMR and a 17 Mach IV.I was thinking of getting of getting a 24 or 26" 17 REM barrel but I have been hearing a lot of good things about the 20 Tactical.I do have a SPR upper and feel that a 20 Tactical will fill the same role as it does.What are your reccomendations between the two and what barrel length would you use?Thanks.SJR556.

I doubt there are many people on this board with experience with these two.  You may be better off throwing it up on the Jim Saubier's board.  The small bore guys hang out there, but mostly bolt action discussion.

I have built 4 uppers in Tactical 20 and about a dozen in 17 Rem.  Both will shoot 1/4" groups at 100 yards.  The 17 seems a bit more finicky than the 20T and some bullets don't shoot very well in the 17, while others pile them into one hole.  The standard 1:10 twist for the 17 seems to work best with the heavier bullets in the 30gr range.  The best for me was always the 30gr Starke, but they are out of business.  So now I shoot the 28gr Calhoon. For 20 and 25 grain bullets, I would lean the twist out to 1:12 in the 17.  

The Tactical 20 shoots everyting pretty well, and the Hornady 33gr V-Max will stack them into one hole at 100 yards.  Tightest groups so far measured .153" at 100yds fired by a gun writer for Small Caliber news.  The published load data on the 20T uses mostly powders that are too fast burning.  Using slower powders seems to work better.  With Berger introducing a bunch of new 20 caliber bullets in the Fall, the 20T should get a jump start.

If the choice were mine, I would go with the Tactical 20.  Same speed as the 17 rem, but you're pushing a little bigger bullet out there.  I have only used 24" stainless barrels on all the small bore uppers that I have built.  

Turn time to build one in either caliber would be about 10 days.

Tony Rumore
Tromix Corp
www.tromix.com

Tony,
   Thank you for responding.I am going to take a look at some of the small caliber boards and see what they say.SJR556.

I would check at www.varminthunters.com

Lots of experience on varmint calibers there and a great bunch of guys. (and gals)