Hi. As a smithy I have found tuners to be of great assistance. I make my own here in AUSTRALIA. Definitely improved the group sizes even on my 22 lr. First photo is of my tuner brake I made for my 22lr Ruger 77-22vt hunting rifle. Went from 1 1/4 inch groups down to 1/4 inch groups. Second photo is of my Ruger 77-22vt taget rifle. Groups are now consistantly tight sub 1/4 inch groups if I do my part. Third photo is of my 308 full bore optical class rifle tuner. Made a huge difference in group sizes. Last photo is of my tuner I added behind the brake. A bit of a custom job and this is on my custom 260 Remington Ruger VT action PRS rifle (REAPER) which has made a huge difference.
The full bore rifle is in 308 Winchester and I run the powder to a velocity node 20 thou off the lands and use the tuner to tighten the groups. The 260Rem PRS rifle I run several projectiles at mag length (customized MDT mags) and have a velocity node for each (140gr SST and 147gr ELD-M) and adjust my tuner for each. Given the numbers on the tuner I just dial in on the predetermind accuracy setting and shoot away. Very repeatable settings. Consistantly under half inch with the SST but better with the ELD-M. FYI my groups are alway 5 shots.
I am keeping a record of barrel lengths and weights and the weight of the tuner to record how the tuner weight to barrel stiffness correlation so as to devolpe a formular so that a tuner can be made at the most effective weight.
Cheers