Introduction
Last Spring, INGO member Top Hat 45 approached me to do some tuner testing and share my experiences with fellow INGO members. He wanted to expose more INGO folks to the world of tuners and he thought that having one noob experience it and tell others was a sound approach. He said he would provide the bench rest, the rifles, targets, and the ammo. What else could I say….I said YES!
[Note: As the following pictures will show, the testing was done in the summer of 2013 but I delayed the writing of this review until recently. O how I wish it was warm again like in these pictures!]
They Don’t Look Like Any Rifles I’ve Ever Seen
Top Hat 45 and IndyGunWorks dropped off the gear on a beautiful day in June. They unpacked what looked like “space guns” to me. Beautiful, long, and heavy!
INGO member MissyB shoots this eye catching yellow rifle!
Notice too, the aluminum bench rest. This was built by Top Hat 45.
Now many of these rifle parts looked familiar to me but I got a surprise when I pulled the trigger. The Suhl trigger breaks at 2 oz!
Some people shoot these bench rifles with their off hand using only their finger and thumb on the rifle. Others will lightly cradle the rifle in the conventional way with their cheek barely touching the stock. Here is a shot of MissyB shooting the Suhl using the first method.
Top Hat 45 didn't let me see the tuner settings. He intentionally spun them around so I would have to do my best to figure it out as I did the testing.
Then next day INGO member Que was at the house so I had him model the Suhl rifle for me. This rifle was the one I eventually used for most of the testing.
You Can Tune a Piano But You Can’t Tuna Fish*
*(REO Speedwagon 1978)
Barrel tuners have been used on rimfire rifles for many years. In the last few years, shooters have been experimenting with them on centerfire rifles.
As I scoured the internet to learn about tuners, I came to the conclusion that they are part science and part art form. There are many people who conjecture about what tuners do to improve rifle accuracy and there is even some impressive finite element analysis articles but the science is not settled.
That they work is clear.
It is beyond my expertise to try to explain how tuners do what they do. However, in simplistic terms, when a shot is fired, vibrations are created in the rifle. There are several types of vibrations occurring at different frequencies and in different planes within the rifle. Bench shooters are interested in finding ways to control the movement of the muzzle as the bullet exits so that they can achieve a high level of shot-to-shot repeatability.
There are nodes or ‘dead spots’ along the barrel. The tuner moves the dead spot to the end of the barrel so that it is moving the least amount possible as the bullet exits. This improves accuracy by imparting the least amount of vertical or horizontal movement to the bullet.
The added weight of the tuner also reduced the frequency of all the harmonics. This may make it easier to find and compensate for the barrel nodes.
Additionally, the current tuner design provides a short dead space after the muzzle crown that may help stabilize the bullet by providing a short distance where the bullet can pass through a zone of expanding gasses that is more stable than the open air. Devices created solely to provide this dead zone are called bloop tubes.
Different Approaches to Tuner Research
Some people approach the tuner topic from the perspective of many years of empirical experience. Their explanations may not always pass scientific muster, but they have thousands of hours experimenting with tuners and various rifles. Don’t discount their observations just because they can’t explain them.
Here’s an example of this type:
Precision Shooting Magazine - March- 2005 (Vol. 52 - No. 11)
Other writers were more scientific. They have done numerous computer and real-life analyses and still can’t determine exactly how tuners work.
One of the better scientific articles I found is here:
Rifle Barrel Tuner Vibration Analysis
Sport of Bench Shooting
I’m intentionally not going to address the sport of bench shooting in this article. It is an enormous topic. People also have many and varied thoughts on the topic. I don’t want to take away from the discussion of tuners in this thread. I also am asking any readers who want to discuss the merits of bench shooting to please start those discussions in new threads.
The Guns
You’ve seen some of the pictures already. Here are the specifications on the three .22 rifles I was working with.
SUHL 150:
Bolt action
Made in East Germany
26 IN Benchmark barrel, 6 groove, 16.5 twist
Pillar bedded
Trigger - single stage factory Suhl trigger set at 2 oz
Harrel / 4000 Tuner
Mid-Barrel tuner by Gene Davis
Weaver T-36 scope
Stock: Bruno McMillan Edge, custom paint
RUGER Tiger Wood 10/22:
MOA stainless receiver with rear mount
Threaded 1" air gauged Douglas stainless barrel, 1-16 twist
Tony Kidd bolt, modified extractor and firing pin
Tony Kidd recoil spring and guide rod
Power Custom bolt handle
Polymer recoil pin
Tony Kidd trigger - straight blade, 4 oz, polished... blade canted
Tony Kidd polished mag release
Volquartzen bedding kit
Ded Nutz 1 piece polished scope mount
Sightron II 36 power fixed scope
Ron Hoehn tuner
Stock: Richards micro fit target thumbhole in Tiger wood laminate, fitted with aluminum plate on forearm for 3" width, butt stock lead-weighted, custom butt plate
RUGER Happy Yellow 10/22
Factory Ruger polished receiver
CPC bolt, VQ extractor and firing pin
Power Custom bolt handle
Tony Kidd recoil spring and guide rod
Polymer recoil pin
Tony Kidd polished stainless barrel, 1-16 twist
VQ bedding kit
Tony Kidd trigger, dual stage, straight blade, 6 oz
Tony Kidd mag release
Ded Nutz one piece polished scope mount
Sightron II 36 power fixed scope
Ron Hoehn tuner
Stock: One-of-a-kind Dan Hawken, "Hawk Tech Arms", narrowed from 4" to 3" forearm, cheek piece modified for shooting Free Recoil, Shortened for LOP, lead-weighed butt stock, custom paint by Tim Landis (to match owner’s Jeep!), custom butt plate
“Getting to Know You”
I shot each of the rifles to get used to their scopes and shooting characteristics before starting the testing. Targets were set at 50 yards.
Tiger Striped rifle
I was pleasantly surprised to see this rifle shoot a 0.757 MOA at 50 yards.
(MOA stands for minute of angle for the grouping measured center-to-center. It’s a great measurement to express firearm precision. )
Yellow rifle with a good view of the bench rest.
Not to be outdone, MissyB’s rifle had a group at 0.754 MOA on my first outing.
Suhl Rifle
I initially had difficulty with the scope on the Suhl. The eye relief “sweet spot” is extraordinarily small and was very difficult to see. (To be expected as the magnification goes up.) I wondered if my wearing glasses was the cause of this. Additionally, the reticle is very thin and hard to make out. I was shooting near dusk.
I soon learned that in regular daylight, it’s much easier to see the reticle.
Designing the Tests
I chose to use the Suhl rifle for my tuner testing since it is a bolt action and I was hoping it was slightly more accurate than the semi-auto guns.
When Top Hat 45 dropped off the Suhl .22 rifle, he cranked on the tuner without letting me see the original setting he had selected for himself.
He told me to do my own testing to find the “sweet spot” or best setting(s) for this rifle and tuner combination.
The tuner on the Suhl has 25 graduations per revolution and will turn 20 full revolutions yielding a total of 500 units for full range. Higher numbers move the tuner weight forward (away from the receiver). Turning the tuner is reminiscent of working with the turrets on a scope. Here is a close up of the tuner on the laminated stock rifle.
There are internet articles describing various methods for adjusting tuners.
After reading several articles on tuning, I decided to do this:
1. Select the ammo to shoot based on temperature. Decided to initially use 1053. It was 82 degrees out with 74% humidity. (I’ll talk more about ammo later.)
2. Set up the rifle and benchrest on my bench. The target is sitting at 50 yards with a small drop in elevation. Shoot 15 rounds to warm the rifle. Confirm zero. Make adjustments to zero if needed.
3. Set the tuner at 0, 100, 200, 300, 400, and 500. Shoot three shot groups. This is Round 1 testing.
4. Find the groups that are the smallest.
5. Shoot from just below to just above this new range in increments of 25 units. This is Round 2.
6. Look for the better groups.
7. Shoot in increments of 10 to find the best groups. This is Round 3.
8. Shoot the best groups in increments of 5. This is Round 4.
9. Shoot more groups in increments of 1 around the current ‘best’ setting to confirm results.
The Suhl has a mid-barrel tuner. However, it will not be moved during this testing. `
For determining the best groups, I took pictures of the targets and then used OnTarget software (On Target Precision Calculator). Results were put into Excel spreadsheets for analysis. [Nerd alert: You don’t have to use the software and spreadsheets to tune your rifle. I chose to go a bit overboard to make sure I wasn’t adding personal bias and because I’m a geek.]
Let the Testing Begin!
Round I
As planned, I shot 3 shot groups at USBR targets having 2” circle targets.
Even before I used the OnTarget software, it was obvious that the 200 setting was the best with the 300 setting still interesting. Here are the actual numbers expressed in MOA.
One improvement that could be made is to shoot more groups at each setting to confirm the results by reducing the affect of shooter variation. However, I chose not to do that because of the ammo expense involved.
Round 2
Based on Round 1 results, I chose to shoot between settings of 150 and 325 with 25 unit increments.
I shot two groups at 150 because I forgot to move the tuner. I hadn’t gotten into the rhythm of adjusting the tuner.
Here are the OnTarget results.
It appeared that the 200 -225 range looked good. I also noticed some interesting groups in the 275 – 300 range.
Round 3
For this round, I chose to shoot at 180 – 220 and 280 – 300 in increments of 10 units on the tuner. I threw in another target at 210 and 290 to get more data points at these interesting settings.
The shooting in the 200 range was disappointing for this round. The 290 range however looked good yielding a 0.412 MOA.
When combining the Round 3 data with previous data, the range around 190-200 continued to look most promising (even with the lackluster shooting in Round 3) and will be the focus of Round 4 shooting.
Ammo
Let’s take a short time out here and talk about ammo.
Top Hat 45 provided the ammo for this testing. He is very careful about what ammunition is fired in his rifles. He uses Eley brand ammo exclusively.
I was curious and did a bit of looking on Midway USA and found that for the type I was using, Eley brand ammo ranges from $14.50 per box of 50 rounds to $23 for a 50 round box of Eley Tenex ammo.
Consistency from shot to shot is critical for bench shooters. To that end bench shooters will buy case amounts of ammo they like so they aren’t switching often.
Eley produces there ammo in a range of velocity ratings (in feet per second) so the shooter can match their ammo to the current weather conditions.
- Air at lower temps is denser: use a faster bullet.
- Air at higher temps is thinner: use a slower bullet.
- High humidity causes the air to be thinner: use a slower bullet*
- Low humidity causes the air to be thicker: use a faster bullet.*
*This seemed counterintuitive to me so I checked. I found that air density decreases as relative humidity increases. This is due to water vapor having a lower molecular weight than oxygen or nitrogen, the key components of air.
Density of air - Wikipedia, the free encyclopedia
The goal of ammo selection is to have the bullets moving at nearly the same speed regardless of differences in temperature or humidity.
I also learned that benchshooters are careful how and when to clean their barrels. After a barrel is cleaned, it takes some shooting it to “season” the barrel properly before attaining the best groups.
Round 4
As before, 3 shot groups were fired and the targets analyzed.
Tuner setting 203 is looking very interesting. I’ve shot it twice with good results both times. There is a decent “valley” from about 200 to 210. The best sweet spots are those that have some width so that they are easier to stay in when there are variations in temperatures and ammunition.
Round 5
I shot from tuner setting of 195 to 209 moving the tuner just one click between groups. I also shot some additional groups around 190 and 290 to provide more data since I was interested in those settings.
I shot my best group of all the testing at setting 280 with a 0.249 MOA.
Results
All the Data
My first reaction when I looked at the summary data was surprise. This rifle was shooting mostly between 0.8 and 0.4 MOA. This is a .22 rifle at 50 yards off a bench. I’ve shot many centerfire rifles that can’t consistently shoot below 1 MOA. The difference between the tuner being in a sweet spot or not appears to be about 0.4 MOA.
To say it another way, if you’re shooting competitively or just want to squeeze the best accuracy out of a .22 rifle, then a tuner may be in your future. In this testing, the tuner seemed to give a 0.4 MOA improvement.
One admonition, don’t slap a tuner on a rifle that hasn’t been optimized with high quality components (barrel, trigger, optics, etc.). They were never intended to fix an average rifle.
In retrospect, I see that I stopped testing a bit too soon. I have some good settings identified, but they need to be shot more to confirm that those settings will consistently deliver 0.4 MOA groups. At the hands of an experienced bench shooter, I imagine the group sizes would shrink.
Multiple Groups
The more times you shoot a group the more likely it is for the average MOA to increase. We add in more and more shooter variation with each additional group at any one setting. However, shooting more groups increases the confidence we have in the average data.
I wondered how many tuner settings were shot multiple times. In the data below, divide the round count by three to get the number of groups shot. I shot a total of 177 rounds, not counting warm-up shots, familiarization shots, and a few shots at steel.
I was surprised. In retrospect, I think I was being a bit too stingy and should have shot more groups. I was concerned with shooting too much of Top Hat 45’s ammo.
Variation
As an aside, I wondered whether there was much variation between each round of testing. A quick pivot chart showed that the average MOA was fairly steady. I expected the last round to do better since I was honing in on the best performing settings. The data shows that the variation added by the shooter was at least consistent.
Tuners on Centerfire Rifles (Shooting a Tuned AR)
Discussing centerfire rifles sporting tuners is beyond the scope of this report, but I’ll give you a quick taste on one that Top Hat 45 let me shoot. He predicts that we will be seeing more tuners on centerfire rifles in the next few years.
At 132 yards off a bench, I was able to place rounds through a 2” hole in a 12” Bobcat Steel target pretty much at will. Very fun to shoot!
Final Thoughts
-- Shooting these fine rifles was eye opening and fun.
-- Tuners make a well-built rifle better by shaving off just a bit more variation. They won’t make an average shooting rifle a tack-driver.
-- You don’t have to understand how tuners work to have them work for you.
-- Tuners have revolutionized .22 bench shooting.
-- It's fun to try out new types of firearms!
-- Shooting someone else’s ammo is REALLY fun!
Acknowledgements
Top Hat 45
For the initial idea for this report and for the generous use of his firearms and ammunition. Additionally for his review of the report draft and unbridled enthusiasm for all things dealing with firearms.
IndyGunWorks
For reviewing and improving the draft of this report and his willingness to help shooters of any level.
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Just for Fun
When Top Hat 45 and MissyB came by to pick up their rifles; we of course had to shoot them some and set off some H2 Products.
H2Targets has some material that can be detonated with a .22LR round. So we did!
2013 07 29 MissyB shooting H2 22 product - YouTube
Here is some standard H2 Product being set off with a .223 round.
2013 07 29 Shooting reg H2 product gallon jug on top - YouTube
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