Gary Wain investigates: benefits of pellet preparation
PUBLISHED: 16:50 13 December 2016 | UPDATED: 16:50 13 December 2016
Gary makes amends for his previous pellet-pulverising antics with a little TLC
Recently, I’ve been meticulously massacring my air rifle pellets in the name of research. Maybe I’m mellowing as I get older, or perhaps I’m just feeling a little guilty, but by way of reparation, I’ve decided to treat my pellets to the munitions equivalent of a spa day.
Those faithful little chaps are going to be weighed, washed, cleaned, rinsed and treated to a nice relaxing massage with essential oils.
If you think I’m madder than a box of frogs, I should explain I’ll be looking at whether or not there are any benefits from pellet preparation. We are going a little further than just washing them, though.
Point of prep
What do we mean by pellet preparation? Well, in simple terms it starts with selecting decent pellets and, more importantly, ones you know work well with your rifle. Having found a brand, the next step is to prepare the pellets to increase accuracy.
The first step for many is to wash them, done by tipping them gently into a plastic basin containing a mixture of a detergent and warm water. The pellets are then agitated gently by hand in the water for several minutes. Depending on the quality of the pellets, you might see a darkish discolouration of the water with many tiny swarf fragments at the bottom.
After draining the water, the process can then be repeated as many times as required so no discolouration or residue is found. The pellets can now be rinsed and eased out of the basin onto a tray, with a lint-free cloth or kitchen towel over it, and spread out by hand.
Drying and lubing
When it comes to drying the pellets, you’ve got a few options. You can leave them to dry naturally, use a hair dryer, and I’ve even heard of people who put them in a warm oven for a few minutes. Personally, the best thing to do is just leave.
Once dry, the pellets can then be oiled, or ‘lubed’. Back in the day there were many weird, wonderful, and for most part secret recipes used on the FT scene. I’m going to use Napier power pellet lube because it appears to be the most commonly used, and at about £4 a bottle it’s not going to break the bank.
To start testing, we need to establish a benchmark control against which all other results will be measured. For once, this is a no brainer, and is simply the pellets drawn straight from the tin with nothing done to them.
Having selected 50 pellets at random from the tin I then segregate the rest by weight. If you’ve ever spent time weighing pellets, you’ll know what an exciting roller coaster of a ride it is.
Some hours, and sore tweezer fingers later, I had five discrete piles of pellets and was shocked by the variance in their weight. The weight on the tin stated the pellets weighed 8.64gr, but out of 200, only 65 were within the 8.60-8.69 (8.6x) range; 62 were within the 8.7x range; 57 within the 8.8x range, and the remaining 16 fell either below or above these ranges. The lightest pellet weighed 8.45gr and the heaviest 8.93gr. The results from the 15.9gr .22 pellets pretty much mirrored the .177 results.
At the end of the day, we’re talking about a difference of about half a grain across the range, the bulk of the pellets falling within one third of a grain of each other. Should I be worried about that variance? Well, that’s where the testing will come in.
Before measuring accuracy, I thought I’d see what could be gleamed from the chronograph. After all, the pellet lube manufacturers claim their product will make the pellets go faster and be more accurate.
Before each batch of ten shots, I refilled the rifle and shot 15 shots to allow things to settle down a bit. Having stuck 10 of each of the three batches of pellets for both calibres through, I came to the following conclusion. Brace yourselves, there’s a bit of statistics coming up. Ready? Okay… deep breath…
Looking at .177 first, the average speed for pellets straight out of the tin was 757fps, with a standard deviation of 7.95. The selected weight, but untreated pellets came in at 760fps, with a standard deviation of 4.18.
The selected, weighed, washed and lubed pellets came in at 762fps with a standard deviation of just 3.20. In simple terms, both weighing on its own, as well as washing and lubing, will give a slight increase in speed, but more importantly a reduction in deviation between shots, which means greater consistency.
The results for .22 were slightly different. Pellets straight out of the tin gave me an average speed of 500.8fps with a standard deviation of just 2.07, much lower than their .177 counterparts. Selected weighed, but untreated pellets saw a slight reduction in their speed with a result of 499.3fps, but a further decrease in standard deviation at just 1.66.
The real surprise came when I shot the .22 weighed, washed and lubed pellets. I was expecting a slight increase in speed and improvement in consistency. Well, with an average speed of 531.8fps I sure as hell got the increase. The problem was this seemed to come at a cost as the standard deviation rose to 2.69, pretty much what we saw with the pellets straight out of the tin.
Once the chronograph testing had been completed, it was time to head down to the range to see what impact the preparations would have on the accuracy of the pellets.
First up was .177, and the untreated pellets straight out of the tin gave me a group of some 18mm. Shooting the weighed pellets brought the group size down by only a small margin to 15mm, but with the weighed, washed and lubed pellets I saw the group size drop dramatically to just 8mm.
The .22 pellets showed a similar, although less pronounced improvement across the process. The ‘out of tin’ pellets evidenced a 27mm group, the weighed pellets a smaller 21mm group and the weighed washed and lubed pellets coming in at 14mm.
It appears that for both .22 and .177, using selected and weighed pellets does have a beneficial effect on overall accuracy and consistency. The results I gathered suggest weighing, washing and lubing pellets has an even greater effect than simply weighing them.
It looks to me as if the accuracy results correlate reasonably well with the chronograph data, in that a reduction in the standard deviation of velocity would connect well with the observed increase in consistency of POI.
Simply put, if the pellets are clean, lubed and weigh the same, they come out of the gun at a very similar speed and so are more likely to land in the same place, than those drawn straight from the tin.
To be honest, I wasn’t expecting these results. I had in my mind that I would end talking about how the benefits are largely psychological. While those effects are certainly a factor, it can’t be denied I pretty much saw a 50% increase in accuracy and a slight increase in velocity. As witty Mr. Wilde once said, ‘Expect the unexpected’.
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