Tuning Harmonic tune those big bore's like we do with our pellet shooters...

[Airgun-hobbyist]

Who tunes for power, small extreme spread and slug diameter based on group size? (Which is what we tend to customary do with big bore's.) Now, who also does harmonic tuning to shrink group size even more after all that previous work?

A member brought to my attention this YouTube video on group-tuning the Western Rattler 357 with slugs recently. Something I found interesting with the video by youTube'r Air Sniper-Song V (who may also be a member here) is that he describes tuning the Rattler's accuracy and tightens the group size with single click adjustments on the power dial (after having found a good slug diameter based on the bore diameter and group size). This is harmonic tuning, and is just like we do with the FX Impact, Huben K1, and other similar small caliber airgun's with power adjustment dials/wheels.

That got me to thinking, I do not read about or see guy's harmonically tuning their big bore, but we would likely benefit a lot more from it. Typically, we set the thing up with a desired power level with the tightest extreme spread and find the ideal slug and/or diameter, all for the tightest group size. But any big bore airgun with a power adjuster wheel like the Western Rattler and Sidewinder and any other big bore with similar power adjusters would benefit from this next step of enhanced tuning.

To what extent do you set your big bore's up?

 

[jasperjet]

well very few big bore air guns have regulators so we have to tune on the bell curve. the new AGT NETVOR LOOKS PROMISING BUT BIG BORES USE SO MUCH AIR THAT THE POWER OR SHOULD i SAY MAXIMUM POWER is hard to achieve with a regulator unless you have a huge air supply. I hate tuning cause every little thing matters but it feels so good when they all go together on a target that I cant quit.

 

[Ezana4CE]

Who tunes for power, small extreme spread and slug diameter based on group size? (Which is what we tend to customary do with big bore's.) Now, who also does harmonic tuning to shrink group size even more after all that previous work?

A member brought to my attention this YouTube video on group-tuning the Western Rattler 357 with slugs recently. Something I found interesting with the video by youTube'r Air Sniper-Song V (who may also be a member here) is that he describes tuning the Rattler's accuracy and tightens the group size with single click adjustments on the power dial (after having found a good slug diameter based on the bore diameter and group size). This is harmonic tuning, and is just like we do with the FX Impact, Huben K1, and other similar small caliber airgun's with power adjustment dials/wheels.

That got me to thinking, I do not read about or see guy's harmonically tuning their big bore, but we would likely benefit a lot more from it. Typically, we set the thing up with a desired power level with the tightest extreme spread and find the ideal slug and/or diameter, all for the tightest group size. But any big bore airgun with a power adjuster wheel like the Western Rattler and Sidewinder and any other big bore with similar power adjusters would benefit from this next step of enhanced tuning.

To what extent do you set your big bore's up?

@Airgun-hobbyist
He’s @AirSniper (SongV) on AGN

 

[357cal]

I tune my big bores. have two: AEA Challenger and the 308 Texan and A few things that help me include a barre band, limb saver, and an external regulator to determine the best PSI for the given slug. In my case, 150gr 940-950 fps at 3100 PSI. For the 308 I have a Mad stock, limb saver, and Yokozuna. I achieved the same numbers with 150gr before the Mad Dog stock, so I might be able to increase the speed.

1. Determine the Twist Rate​

First, confirm the twist rate of your barrel. This is usually marked on the barrel itself or mentioned in the manual. It’s often expressed as a ratio like 1:12, which means the bullet makes one full turn every 12 inches.

2. Select the Pellets​

Choose pellets or slugs that suit your shooting needs. Different weights and shapes can impact accuracy and velocity, so experiment with a few options to see which works best for your specific setup.

3. Adjust the Power Settings​

For optimal performance:

• Start Low: Begin with lower power settings. Your PCP should have an adjustable power knob or screw.
• Gradually Increase: Incrementally increase the power and measure the velocity using a chronograph.
• Record Data: Keep track of the velocities and accuracy as you increase power settings.

4. Test and Observe​

• Accuracy Testing: Set up a target at a consistent distance (e.g., 50 yards). Shoot a series of groups, making sure to note any changes in accuracy.
• Consistency: Look for consistent group sizes and points of impact. High velocities might lead to more deviation, while too low velocities might reduce penetration and power.

Finding the Optimal Velocity​

• Calculate Bullet Stability: A bullet's stability is influenced by its velocity and twist rate. You can use the Miller Stability Formula (MSF) or online calculators to determine the optimal velocity for stability.
• Chronograph Testing: Use the chronograph to measure the speed of your shots and adjust your settings accordingly.
• Balance Speed and Accuracy: The goal is to find a balance where the bullets are stable in flight and maintain consistent, tight groupings.

 

[Arkansas_Airgunner]

I bought a Limb-Saver Harmonic Dampener for my .457 Texan. Fiddled with it for quite a few rounds until I was able to shrink my group size down to 1.5"‐2" at 75 yrds. Pretty pleased with the results as I rarely hunt/shoot any further than 100 yards with it.