Fascinating video on pellet speed and power loss over distance

[andrewM]

Occasionally, I watch some of the shooting videos on Youtube, a number of which are interesting and informative.

I haver just watched this one:

https://www.youtube.com/watch?v=cyTZGOMSMUk

Airgun Pellet Speed Power Test: 0 to 50m .22 +.177- FPS + FT LBS - from AirgunGearShow.

It tells us that the ft/lbs loss of a 177 pellet is greater than that for a 22 - something that many of us already knew. However, it also explains - and this I found most interesting - that a 22 with a lighter pellet v a 22 with a heavier pellet (the same applies for 177), will result in the lighter pellet losing its energy (in ft/lb) so fast that this has already made an impact within 5m of the shot leaving the barrel.

Here is an example: Using Superdomes (14.5g) the ft/lbs is 10.83 at the point of leaving the barrel and the JSB Exacts (15.9g) are 10.82 ft/lbs at the point of leaving the barrel. However, at 5m, the S.domes have fallen behind already, at 9.57ft/lbs whereas the Exacts are at 10.39ft lbs. By the time we reach 40m, the S.Domes are recording 5.54ft/lbs against 7.05 ft/lbs for the Exacts.

It is worth watching this 12 min video.

It would be interesting to know how the trajectories vary and if there is a cross-over point, at which the lighter pellet falls below the heavier pellet in its trajectory. I wonder if any reader can advise? Many people buy the lighter pellets, such a S.Domes, because they expect the trajectory to be flatter than with a heavier pellet such as Exacts or AA, for example. But this might be an error, if the lighter pellet demonstrates a more curved trajectory.

Rgds
A

[Halimede]

School was a long time ago for me but...
Drag increases at the square of airspeed. A pellet has to shove air out of its way so loses energy. For a given speed and weight a wider pellet shoves more air so loses more energy but a heavier pellet (at said speed) has more energy to lose so slows, well slower. Hang on, I might need to think about this some more.

[Shed tuner]

superdomes are not a good example of a lighter pellet, as they have particularly poor ballistics. The Falcon Accuracy Plus / JSB express / RS are much better, and weigh even less (13.43 / 14.x grain)

[zephyr]

Ah, those were the days. I subscribed and avidly watched Giles’ YouTube channel. As he says at the end “…there are variables…”, “…take this as guidance, not complete fact…” and “…overall findings would play out…”. It would be much better (although expensive) to have multiple chrono’s set up, so you are measuring the same pellet thus eliminating variability between shots.

[Shed tuner]

when I've done this before, like most others, I have two chronos, one near the muzzle, and one around 35 yards. Allows you to calculate BC pretty well, and certainly good enough for comparative purposes.

[TonyL]

Thanks for posting, Andrew, although this won't be too surprising to many who may have read various posts on here before (especially when ballisticboy jumps in) and some excellent articles by Jim Tyler. As JB says, the Superdome doesn't seem to be a very efficient pellet ballistically. The BC is key (dictated by many constituents) and this also has a huge bearing on wind drift susceptibility . All very interesting stuff. The only way to get the true BC for a pellet in your own gun is to conduct your own tests, as it varies from gun to gun, but there are some handy charts available (giving a general idea) that make interesting reading, like the ones available on the U.S Hardairmagazine site.

[rapidresponse1]

very interesting thanks for posting

[andrewM]

Some very interesting replies - thanks. Probably, we need more examples to reach a firm conclusion, therefore. I am hard-pressed, like Halimede, to recall my school physics but what surprised me was the fact that the S.Dome had lost power by as early as 5m out of the barrel compared with the heavier pellet. However, perhaps Domes are a poor example, as some have suggested. That said, they have demonstrated good accuracy in some air rifles and, not least, they seem to do very well from both an accuracy and power viewpoint in the old .22 British barrels, such as the pre-war BSAs and Webley Mk3s.

Rgds
A

[TonyL]

The good ole Superdome is a trusted favourite in a fair few of my rifles too, Andrew. Just not as efficient as some. For many, many years they were my go-to pellet for all my guns as they were always reliable and accurate in .177 and .22. I don't think I have a rifle that doesn't like them. It's just that, in more recent times, I've tested with others and found some to perform better in some of my rifles, most notably the H&N FTT in Weihrauch barrels. And when I say "better" I'm referring to pure accuracy / tightest group sizes, not downrange velocity retention. Accuracy is always King. When setting power, the 'Dome often gives lower muzzle energy in many springers, too, so another thing to be mindful of.

[andrewM]

The good ole Superdome is a trusted favourite in a fair few of my rifles too, Andrew. Just not as efficient as some. For many, many years they were my go-to pellet for all my guns as they were always reliable and accurate in .177 and .22. I don't think I have a rifle that doesn't like them. It's just that, in more recent times, I've tested with others and found some to perform better in some of my rifles, most notably the H&N FTT in Weihrauch barrels. And when I say "better" I'm referring to pure accuracy / tightest group sizes, not downrange velocity retention. Accuracy is always King. When setting power, the 'Dome often gives lower muzzle energy in many springers, too, so another thing to be mindful of.

Thanks Tony! Yes, S.Domes are an excellent all rounder but there are some pellets that are particularly accurate in certain barrels. Thus, Accupels are hopeless in some, like scatter guns, but pinpoint in others. I have found, interestingly, Excite, H&N Pointed and H&N Sniper superb in my Longbow and one or two other rifles - but would have to check which ones. I keep a folder, after extensive testing, to show what goes best with each. This is a lengthy process and cannot be done in one session because one gets tired and therefore less accurate. It would be good to have a dedicated section here for all rifles and the pellets best suited to them.

I have found the Dome to give good velocity too in my Mk3s and BSA Standards, as well as accuracy.

I bought some Hades to try out, which I will do when I find time. I have heard good things about these and, equally, also want to try H&N Terminator to see how these go.

Rgds
A

[zephyr]

I read many years ago, and at regular intervals since, that it is not just which pellet make/type/weight that is important, but also which batch number. I have found this to be true.

But what is it about a particular batch that makes them better than other batches? The ductility or the mix of metals in the ‘lead’? The weight? The slight differences in pellet shape between dies? The head size? The reduced variation between pellets? Could it be mental?

Based on blind testing (not scientific understanding or hypothesise) there does seem to be a connection with head size and size of groups. In my rifles, 4.52 and 4.53 give the smallest group sizes. It is important to know that I refer to the actual head sizes, not what is said to be in the tins.

[angrybear]

An extremely interesting video, I wish he'd had a .20 to compare .
However
Speed/velocity is not the be all & end all, what matters is the kinetic energy in the projectile, which is the speed X the weight

If a kid on a scooter hits you at 20 mph, it might knock you back a few steps,
If a car hits you at 20mph, it's knocking you over & you're probably off to hospital,
If a 40 ton truck hits you at 20mph, likely as not the impact kills you.

The OP mentions trajectory, but we use sights & scopes where the zero range (or trajectory path ) is changed to suit our requirement, which makes life difficult as the zero range alters the horizontal angle of the barrel.
but a program like chairgun can show you the actual trajectory worked out for the exact details you enter, so you can select a different pellet & note the difference.

[gsxrman]

This is sounding like a "power " induced thread.
like someone has already said, the Make, Calibre, Shape or weight are all irrelevant really.
Accuracy is what counts, in the real world and not in the theory or physics dept.
There are just too many variables in weight, size and probably shape to actually calculate accurately. One pellet fine but not 500 varying pellets out of a tin.
real world tests need to be carried out, old school style to find the most accurate pellet for your individual rifle.
I use 7.9 Premiers still, as I haven't found a pellet that matches its accuracy and consistency in the wind at range.
JSBs foe example, are as accurate in doors but not in the wind where it counts.
At 55 yards there is more than enough energy left to flatten a target or kill a rabbit. That's all that matters to me.
.22 Bisley mags retain tons of energy but if you cant hit the mark, that energy retention is a waste.