Gary Wain investigates: ballistic properties of .177 pellets
PUBLISHED: 06:22 02 February 2017
Gary continues his series on pellets, with some fascinating experiments
I’ve come to the conclusion that I have something of a pellet fixation. There’s no point in denying it, so I might as well embrace it – I think I enjoy teasing out some of the detail behind the known truths of airgun shooting. The thing is, I’ve inadvertently shown that some of the ‘truths’ are, at best, not 100% accurate, and at worst, more like myths.
After the third article on the comparison between .177 and .22, I planned a series of articles to look in more detail at not only at the different calibres, but the effects that pellet weight, shape and size have on ballistic material.
In this, the first in the series, I’m looking at .177 pellets of equal, or near equal, weight, but of different head design. I’m aiming to determine not only which makes the biggest hole, but which is the better design for hunting. Thanks to Phill Price, editor of Air Gunner, for inspiration for these experiments.
Pellets on test
Having sourced a selection of over 30 pellet types in both calibres, I selected four .177 brands that weighed 10gr, or as near as. The reason for selecting 10gr was simply that there just so happened to be quite a few types in this weight band. First to be selected was the H&N Hunter Extreme. The H&N has a small X cut into the face of the pellet, causing it to expand on impact, which slows it down rapidly and dump more of its energy into the target material. At 9.26gr the H&N is also the lightest pellet in the test.
Next up, it’s the turn of the Daystate FT Heavy. At 10.25gr, it’s not particularly heavy in general terms, but is on the heavy side for a traditional domed pellet, with most weighing in at the 8gr mark.
The third pellet was the Remington Thundersport. It certainly takes the prize for the pellet with the most macho name, especially when you consider it’s simply a 10.6gr flat-headed wadcutter.
Last in the selection we have the Skenko Ultrashock - what is it with these names? The hollow-point weighs in at 10.3gr and is quite a long-bodied pellet, with a thin skirt and a hollow point so deep that you have to look at it twice to work out which end goes in the breech first.
Time to experiment
Selecting the ballistic test material was easy – the terracotta wax I’d used previously. This stuff is absolutely fantastic in how it simulates the way flesh reacts when struck by a pellet, the only proviso being that you have to heat it up to about 20 degrees in order for it to become malleable.
As it was important for the terracotta wax be exactly the same temperature for all the shots, it was necessary for me to buy in a few kilos so I had four blocks to shoot at in quick succession. I even went so far as to buy a meat thermometer to make sure all the blocks were evenly warmed. I opted to invest in some plaster of Paris in order to take casts of the holes, to better demonstrate the ‘cavitation’ effect of the pellets.
Armed with my Daystate Pulsar, and with a kitchen that looked like Mary Berry had been busy making icing-sugar-covered fudge brownies, I set about gathering data. I have to say, I was quite pleased with the results. The first fired was the H&N Hunter Extreme, which left a 24mm entry wound and an even bigger, 36mm internal cavity, travelling some 83mm into the ballistic material.
Close examination of the pellet revealed the cross head had deformed as intended, and the large internal cavity indicated the majority of the kinetic energy had been dumped in the material. Accuracy wise, the H&N was a good deal better than expected, being the second most consistent grouper in the test behind the Daystate.
Next to be fired was the Daystate FT Heavy. This dome-headed pellet left a much smaller, 18mm entry wound, and the internal cavity not extended beyond that diameter. The wound track tapered progressively, and the pellet actually exited out of the test material having travelled the full 120mm of its depth. The Daystate was devastatingly accurate.
The third pellet was the Remington Thundersport. I expected the flat-headed pellet to produce a wider wound track than the Daystate, but wasn’t sure whether it would be bigger than the H&N. As it turned out, it fell about halfway between them, with an entry hole of 21mm, expanding to 26mm, and a total penetration of 74mm. It was the least accurate by a large margin, so not on my list to test further.
The last pellet fired was the Ultrashock. The Skenko gave an 11mm entry hole, expanding to 16mm, and travelled 96mm into the test material before coming to rest. Examination of the pellet head showed that unlike the the H&N, the Skenko’s hollow point had failed to deform and so the full ballistic potential of the shape was not realised. This may be due to the lip of the hollow point being too thick to be affected by the impact. From an accuracy standpoint, the Skenko was much better than the Thundersport, and only a little off the pace of the H&N.
Best on test?
I think we can exclude the Remington Thundersport. Despite impressive ballistic effects, it wasn’t nearly accurate enough to be used in the field at anything over about 10m - great for rats, but nothing else.
Next for the chop is the Skenko Ultrashock. I really wasn’t that impressed with the ballistic impact as it was only a little larger than the Daystate, and with about average accuracy it has little else going for it.
I think the Daystate is the better pellet, it was certainly the most accurate in the test. It may well make it into my gun bag, for that factor alone. If you’re shooting at extreme range, you’re going to want its accuracy over anything else.
But what I’m going to say next might upset the apple-cart – if you’re hunting at the more recommended 35(ish) yards, then the H&N Hunter Extreme is accurate enough. It’s not quite as accurate as the Daystate, but enough to guarantee a head shot. Add the devastating wound track generated by the pellet head deformation and dumping of kinetic energy, and you have a winning combination.
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