Biologist wrote;
Without reading the study myself, and just going with the info presented, I have many questions about was this even a valid scientific test? I stand to be corrected on what follows, as I am taking this at face value of the information presented.
The information states that the shooting was done in the prone position with a bipod and rear bag. This opens up a can of worms for a plethora of un-controlled variables that destroys the test's validity.
The only way to test for the effects of a tuner is to clamp the rifle into the rigs like Lapua and Eley use in their test tunnel labs, in order to eliminate the shooter's muscle and skeletal variability. There should be no human holding the rifle, no bipod, no rear bag.
There is still scientific debate on whether or not a solid clamped rimfire barreled action, as is done in the test labs, creates unnatural harmonics that otherwise would not happen when the rifle is allowed to free recoil, or have energy absorbed by the shooter's body. I am sure they have thought of this and have equipment that lets the test rifle recoil on a slide of some sort, in order to test if this is an issue. In centerfire of course, the rail gun guys have this recoil function well engineered to deal with this very issue of nullifying nasty feedback harmonics. The human body and friction on sandbags also helps to absorb energy and reduce the feedback harmonics when the rifle mass "wants" to move backwards. But a human body cannot possibly be consistent in this controlled free recoil.
From the reading and equipment list, they were attempting to simulate the true competition situation that rimfire PRS shooters would be doing, which is great, and useful, don't get me wrong. However that methodology introduces all kinds of user interactions for opening up groups and affecting score on bullseye targets that cannot possibly be held consistent.
My hypothesis: Simulating real rimfire PRS situations is not the way to control variables in order to test if barrel tuners make a difference.
MDT chassis: These have notoriously bad buttstock keels, or total lack thereof, for tracking in a proper bench rest rabbit ear bag. MDT's accessory bag rider is the wrong shape for tracking inside a proper eared BR rear bag. The MDT chassis itself is superb, but its buttstock is not made properly for true bench rest precision IMO. Its made for PRS where a large surface area is made to sit in a squeezed rear bag or other surface.
Benchrest buttstock keels are trapezoidal in shape with a flat bottom, designed by the user, and the width of these are matched to the sewn width of the base of the custom rear bag rabbit ear bag (see below for more on rear bags). Bench rest shooters specify the sewn width when ordering custom rear bags to fit their rifle's specific buttstock keel so that it will track backwards perfectly straight.
Bipod: No high precision/high accuracy tests can be done with a bipod to test a tuner, or other rifle and ammo components. A bipod is a handicap specified by the rules on purpose to simulate a field shooting equipment condition where shooters would not be lugging around heavy steel/iron mechanical front rests. Benchrest rifle forearms have a flat (or bi-railed) 3 inch forearm base (or wider when rules allow) to resist torque, provide free recoil on flat sandbags on mechanical BR rests. These VERY heavy front BR mechanical rests have squeezer sides for the forearm for this solid support and recoil tracking straight back. If a bipod shoots better precision and accuracy than a heavy mechanical front rest, then benchrest and F-open shooters would use it. Bipods are used in competition as an applied restriction in gear where a heavy mechanical front rest is not allowed by the rules (or its impractical such as in PRS barricade shooting), meaning that the shooter requires considerable skill using the bipod to compensate for the advantages of the heavy mechanical front BR rest.
Rear bag: The AG Schmedium plus the bipod indicates that shooters were holding the rifle with muscles and skeleton, squeezing the rear bag to adjust for elevation and windage, and this cannot possibly be as accurate or precise as a clamped in barreled action in a tunnel testing facility, and as mentioned above, it will not provide equivalent accuracy and precision of heavy BR mechanical rest support equipment where geared wheels, rods or joysticks are used for fine elevation and windage adjustments, fully supporting the rifle, and the shooter may only be touching the trigger.
12 oz trigger: Rimfire open benchrest shooters use triggers down to 1 to 2 oz for a reason: less shooter induced error. But by the rules they are single loading at the bench, NOT feeding from a magazine, and not moving. Rimfire PRS shooters use magazine fed rounds and are moving with a loaded rifle and manipulating it on barricades in a variety of shooting positions, and under stress of the clock. Therefore of course the trigger must be a heavier pull for obvious safety reasons. The 12 oz trigger, while excellent and safe for rimfire PRS purposes, will induce some inaccuracy and loss of precision from the shooter's movements, especially when under duress of difficult physical positions and time limits. The info above stated that the shooting position was prone using bipod and rear bag, which is good for simulating the most stable position a rimfire PRS shooter would be in, but it does not allow for control of all variables - very good, but not sufficient.
I don't mean for this to be a rant, and as stated above, I stand to be corrected if I am missing something from their testing methodology.
In a related topic, I am continually disappointed in seeing all the great videos on YT that purport to be testing ammo, or tuners, or other gear, and yet they are shooting outside in windy conditions, with not fully supported rifles, with rifles starting from a clean condition and being progressively fouled (which can affect POI and group size as the internal chemistry of the bore gunk changes), where their muscles are inconsistently moving to control the rifle - these tests of specific equipment are all mostly bogus. Great intent, great entertainment, but these are not scientific tests.
Videos of testing rimfire gear in laboratory shooting tunnels is incredibly boring to watch. I get it. But it has to be done in a lab if you want to test specific devices like tuners.
And....the ammo was SK LR Match, which is going to have some crazy random fliers, guaranteed. And how many lots of this ammo did they test, to reduce or eliminate lot to lot inconsistencies?
BTW, I am a big fan of Brian Litz. I have not read his books, but I catch as many YT videos as I can of him taking about stuff. I have learned a huge amount from him from his online presentations.
