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The centre of drag, like the centre of gravity, for the pellet lies on the pellet centreline, with no particular longitudinal point of acting. The centre of pressure, which is completely different, lies behind the centre of gravity and thus produces stabilizing moments about the centre of...

Slugs do not get more stable as speed increases. In fact, like most spin stabilized projectiles, at subsonic speeds the faster they are fired the less stable they get. Depending on the stability factor of the slug, having less stability may reduce group sizes, but there are plenty of other...

A rebated boat tail is claimed to improve the intermediate ballistics, thus reducing group sizes compared to a straight non rebated boat tail. The main problem with rebates is that they increase the effective boat tail angle, which is already excessive on many slug designs, making it difficult...

Simples. Because I read it on this one first. :)

Approximately 11.7 degrees outside, about 12.1 degrees internally.

Some of the reasons lead free pellets give larger group sizes were discussed here. https://www.airgunnation.com/threads/lead-and-lead-free-pellets.1283547/

Not really semantics, differentiating between the two is very important if you want to understand what is happening. As for the 100 yard groups in any weather conditions, to try to ascribe the differences in group sizes to BC alone is pure folly and is ignoring the most important basic...

You are talking about accuracy, where BC will have an effect. I was talking about group size, or precision in US nomenclature, which is not the same thing as Bryan Litz explains in his book.

Unless you are shooting on a windy day with the wind varying a lot, BC will not help your group sizes, that is much more complex.

Both MERO and the original Chairgun will give maximum ranges.

GA is not a suitable drag function for slugs, particularly at speeds approaching 1000 ft/sec. The BC quoted by FX may well be based on the G1 drag law again not suitable for slugs giving artificially high values at higher speeds, good for sales, not good for trajectory modelling. RA4 is better...

This is why we want the matching Reynolds number where possible. Many tunnels work by using accelerating or slowing air speeds to measure over a range of Mach numbers, trouble is there is something called aerodynamic hysteresis which means you get different results depending on if you are...

If you want to learn how flares stabilize projectiles, look up flare stabilization in any reputable projectile aerodynamics text book. I was calculating and predicting the stabilization of flare stabilized projectiles for 40 years as a gun projectile aerodynamicist, and they all flew as...

You will have to watch your barrel twist rate with slugs. The twist rate will dictate a maximum length for the slugs which can be stabilized. Boat tails make slugs less stable and require a faster twist rate to be stable than the equivalent cylindrical based slug of the same length.

All types of stability, including aerodynamic and gyroscopic stability, are dependent on moments, not forces. The drag force has practically zero moment about the CG, whereas the normal forces produced by the flare when at an angle of yaw produce correcting moments about the CG. Drag has little...

I am afraid you will have to wait a very long time then. I did not suggest that the reports were wrong, just that the pellet shapes chosen led to a biased conclusion. This can be easily seen and checked in the calculated drag coefficients, which are higher than those derived from free flight...

On the first of these references, it is unfortunate that the tests were all carried out on relatively high nose drag pellet designs, all with recognized poor BC values. This led them to make the wrong conclusion on where the majority of the drag is generated. The wind tunnel tests on pellet...

I don't personally know of any 9 year old that can throw a shuttlecock at 38000 RPM. The spin rates of pellets, bullets, shells or any spin stabilized projectile make a huge difference to its behaviour in flight, with or without shape defects. You cannot use shuttlecocks as examples of how...

No, basic aerodynamic knowledge as learned in the most basic aerodynamics courses. Nothing to do with "opinions"

It is highly unlikely that pellets will tumble, as the gyroscopic stability shows large increases as the pellet slows down. There can be a large increase in peak yaw angles at longer ranges, as dynamic stability appears to be poor. This would seem to be more likely on heavy pellets where the...