I've been really interested in tuners and their practicality, ever since they've started to explode in popularity in the "practical" shooting disciplines (PRS type events). I find it a fascinating topic, and I've even done my own testing with a tuner/brake combo.
These are my thoughts on the subject on the subject, as it pertains to the type of shooting I have experience in (field shooting, PRS, etc.):
- Through my own extensive testing (many 5-round groups), a tuner did not "shrink" my group sizes (also shooting 6BRA).
- 2or 3 shot groups are statistically irrelevant. You won't be able to find an optimized tune by shooting 2 or 3 shot groups, unless you fall into it by dumb luck. There is so much statistical variance to group sizes, that capturing only 2 or 3 round groups to try and determine if the tuner is making your groups shrink (or not), is a statistically insignificant and irrelevant sample size. This is like trying to optimize charge weight by using the "Satterlee method".
- Disciplines that have been using tuners for decades (BR, F-class), do not use tuners to "shrink groups". They do a full load workup completely independent of a tuner, optimizing the ammo to the rifle. A tuner for these uses is to keep their ammo "in tune" with the rifle as environmentals change over the course of shooting -we are talking very minute changes, that aren't really practical for "practical" shooting disciplines, and even the results in BR and F-class are debatable (as to how much the tuner is helping).
- Now that tuners are becoming popular in disciplines such as PRS, tuner advocates and sellers of tuners claim you can shortcut the reloading process with tuners. I think this is very ill-advised advice for numerous reasons. I don't think you will ever hear anyone from disciplines with decades of tuner experience advocate for this. Also, tuner results can be very difficult to parse and draw conclusions from, and you become reliant on the tuner to work with your ammo.
- Some say you can make factory ammo more precise with a tuner. I find these claims dubious at best, and the "evidence" presented so far is less than compelling. However I'm certainly open to this concept, I haven't tested it myself, but the current data to support this is very weak from what I've seen.
- Tuner results can be very difficult to interpret. Not only are people generally using too little sample sizes in which its nearly impossible to extract a meaningful conclusion from, but interpreting exactly what the tuner is doing, while trying to determine if any seemingly "errant" shots are from the tuner or from the shooter, can be very difficult. Top BR gunsmiths like Alex Wheeler typically recommend to their clients to shoot out a barrel or two just in competition, prior to adding a tuner. It's another variable to the equation, one that can add a lot of confusion. I personally believe that people should have a very strong grasp of the fundamentals, as well as internal and external ballistics, before adding another variable/input that manipulates ballistic results.
- Adding a tuner to a "practical" rifle is adding another potential failure point, and another variable to control. By their very design, tuners (through use of a collared weight), are designed to shift POI. If this tuner comes loose, it will create problems downrange.
Personally, I'm not sold on tuners. Perhaps for BR and F-class disciplines they have their purpose (both styles of competitions I have no personal experience in and can't speak to). But for practical style disciplines, I think their practicality and benefits are oversold and their downsides ignored.
