FWIW, the optimum Contender carbine bull barrel length for the 17HMR is 19" - proven out by Fred at Bullberry (full report on his web site). I have the prototype (first) 17HMR carbine barrel ever made for a TC, and my Bullberry is 20". It hangs very well with the extra heavy custom stock set also done exhibition grade by Fred to commemorate the birth of the Hummer. It shoots even better... best 5-shot 100 yard group so far for the No. 1 is .182".