Posts Tagged ‘oiling pellets’
by Tom Gaylord, a.k.a. B.B. Pelletier
Let’s begin testing the effects of oiling pellets. There are numerous ways to approach this issue, and I have to pick one at a time and limit the test to just that. But I think as long as I’m testing one aspect, I ought to test it thoroughly so someone can’t come back and second-guess me later in the report.
So, today I’ll test with one rifle, and the next time I’ll test with another. What I won’t do is test with each different brand of airgun, just to see what will happen. If a powerful gas spring rifle performs in a certain way, I’ll assume that all powerful gas spring rifles are going to do the same. If the difference between dry pellets and oiled pellets is close, I may do additional testing; but if there’s clear separation, I’ll accept that as the way it works.
What am I testing?
The question that started this experiment was, “How much faster will oiled pellets shoot than those that are not oiled?” One reader has asked me to also test this downrange because he wonders if a thin coat of oil changes the laminar flow of air around a pellet. I may get to that at some point, but for the present I’m just concerned with muzzle velocity because all pellets slow down after they exit the muzzle — oiled or not.
I suppose this needs to be tested in all three powerplant types, but today I’m testing it in a spring-piston powerplant. Today’s gun is a weak powerplant, so next time I’ll test it in a more powerful gun.
I’m using an HW55 SF target rifle to test three pellets. This rifle is a variation of the old HW50 rifle, so it shoots in the 600-650 f.p.s. region with lead pellets.
Since oiled pellets will leave a film in the bore, I tested all pellets dry first, and then tested the oiled pellets afterwards. Before the first test shot with oiled pellets, I fired two pellets to condition the bore. That turned out not to be enough, but I’ll come to that later.
I’ll test the three major pellet shapes in this test. They’re the wadcutter, dome and pointed head. There are other shapes, like hollowpoints, but they’re based on one of these three main shapes, so this is all I’m testing.
How I oil pellets
I oil pellets in the following manner. A foam liner is placed in the bottom of a pellet tin, and 20 drops of Whiscombe Honey are dropped onto the foam. Then, a single layer of pellets is spread on the foam, and the tin is rolled around. I shake the tin lightly to move the pellets around…but not enough to damage them. Whatever oil transfers to the pellet is all the oil it gets. I’ve been doing this for many years and it works well.
The pellets end up with a very light and uniform coat of oil. When I handle them the tips of my fingers become oily, but I can’t see any oil on the pellets. Other people use more oil than I do, but this is what I am testing.
Whiscombe Honey is a mixture of two-thirds Hoppes Gun Oil (not Number 9 bore cleaner!) and one-third STP Engine Treatment, by volume. Shake the mixture until is takes on a light yellow color. It will look like thin honey, hence the name. This mixture should not detonate easily in a spring gun.
Test one — dry pellets
Crosman Premier 7.9-grain pellets were the domes I tested. The average velocity for dry Premiers was 606 f.p.s., with a low of 577 and a high of 616. So, the spread was 39 f.p.s. The average muzzle energy was 6.44 foot-pounds.
For wadcutters, I tested Gamo Match pellets. The average for dry pellets was 652 f.p.s., with a low of 640 and a high of 663 f.p.s. The spread was 17 f.p.s. The average energy was 7.14 foot-pounds.
H&N Neue Spitzkugel
The pointed pellet I selected was the H&N Neue Spitzgugel. When shot dry, they averaged 601 f.p.s., with a low of 585 and a high of 620 f.p.s. The spread was 34 f.p.s. The average muzzle energy was 6.81 foot-pounds at the muzzle.
Now, I shot two oiled pellets through the bore to condition it and began the test.
Oiled Crosman Premiers
Oiled 7.9-grain Premiers averaged 591 f.p.s., but the spread went from a low of 545 to a high of 612 f.p.s. That’s a spread of 67 .p.s. The average energy for oiled pellets was 6.13 foot-pounds. I did notice the pellets were going faster at the end of the shot string, so I thought I might come back to them after testing the other pellets.
Oiled Gamo Match pellets
The oiled wadcutters averaged 658 f.p.s. — a slight gain over the dry pellets. But the real news was the spread, which went from a low of 651 to a high of 663 f.p.s. Instead of a 17 f.p.s. for the dry pellets, the oiled pellets gave a spread of just 12 f.p.s. That’s too close to draw any conclusions, but it’s interesting. The average energy with the oiled pellets was 7.27 foot-pounds. So, with the oiled pellets, the velocity went up — along with the energy — and the shot-to-shot variance went down.
Oiled H&N Neue Spitzkugel
Oiled Spitzkugels averaged 609 f.p.s. — which was a small increase over the same pellet when dry. The average energy was 6.99 foot-pounds. The spread went from 585 to 620 f.p.s, which was identical for the same pellet dry. Velocity and energy were both up slightly from dry pellets, and the shot-to-shot variance remained the same.
By now, it’s obvious that the bore needed more than two shots to condition it, so I retested the oiled Crosman Premiers. The second time the oiled pellets averaged 604 f.p.s., which is just 2 f.p.s. slower than the same pellets dry. But the spread that was 67 f.p.s. on the first test of oiled pellets and 39 f.p.s. with dry Premiers now went from a low of 594 to a high of 613 f.p.s. — a much tighter 19 f.p.s. total. The average energy was 6.40 foot-pounds.
From this test, I observed that these three pellets either remained at the same velocity or increased very slightly from the light oiling I gave them. In two of the three cases, the velocity spread got tighter when the pellets were oiled.
I further observed that it’s necessary to condition a bore with oiled pellets before doing any testing. As a minimum, I would say that 20 oiled pellets should be fired before testing.
These are very small differences from oiling; and although I can’t draw any conclusions yet, I would think that such a small change is not enough to matter. It hardly seems worth doing at this point. However, there’s still a test to be done in a powerful airgun. Until we see those results, I think it’s too soon to say anything for sure.
Although the question that drove this test was how much faster oiling pellets makes them shoot, I think we still have to take accuracy into account before forming any opinions.
And now for something completely different
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by Tom Gaylord, a.k.a. B.B. Pelletier
This report will be lengthy because I want to test several aspects of oiling pellets. For starters, I want to test it with spring guns, PCPs and CO2 guns just to get a complete picture of what, if anything, oiling pellets is doing in each of those powerplants. I’m interested in velocity because of the question that spawned this blog, but accuracy might also be interesting to test.
We received this question in the following form. I will paraphrase, but this is the gist of it, “How much faster do pellets go when they are oiled?” That question came in on one of our social networks and was referred to me for an answer. Well, you know me! Give me a topic and I turn it into a week’s worth of blogs. But this question really begged for the full treatment because there’s so much to cover.
When I got interested in shooting airguns as an adult in the middle 1970s, the question of oiling pellets wasn’t around (as far as I know). In talking with the late Rodney Boyce, I learned that the oiling question really came to a head when PCPs first started being used in the early 1980s. A PCP shoots very dry air, and their barrels are made from steel; so, at the higher velocities, they tend to get leaded bores. Some shooters were also oiling pellets for their spring guns; but a lot of the time they did it because they washed the pellets, thinking the black compound on them was dirt. In fact, it was anti-oxidant to keep the pellets from turning to white dust. Had they just left the pellets alone, they wouldn’t have oxidized.
In defense of the spring-gun guys who washed their pellets, though, some brands did have a lot of lead swarf (flakes of lead from the manufacturing process) inside some of the pellets, and vigorous washing did remove it. But then the pellets needed to be oiled again, or they would quickly oxidize.
Why we oil pellets
We oil pellets for two reasons. The first is to prevent the oxidation of the lead after washing. The second is to reduce the leading of the bore, though this is principally a PCP problem. Other pneumatics either shoot too slowly or they have brass or bronze barrels that do not allow the lead to attach itself, so they do not lead up.
Do oiled pellets shoot faster?
That was the question that started this report. I’ve tested this in the past and found that with a PCP shooting .177 pellets at 850-900 f.p.s., oiled pellets went slower, not faster. But that was just one test, and I don’t want to say what oiling will do for other guns until I do some more testing.
I’ll tell you this — oiling pellets became such a hot topic in the late ’90s that people were swapping their favorite secret formulas on the internet. And I know one UK company that sells an oil for pellets that they still claim gives increased velocity. Well, that’s too good to pass up, so I’ll test some of their oil in this test.
Not just oil
Don’t think that oil is the only thing people put on pellets. I remember lengthy discussions of how to apply a thin even coat of wax on pellets. Then, the topic shifted to what kind of wax to use! One guy went so far as to specify a high-tech boat hull compound called Bo-Shield for his pellets. When he talked about it his eyes got that faraway stare, as though he was transcending the real world and entering the spirit world.
What I will test
The first thing I want to do — have to do, in my mind — is test what the application of oil does to the velocity of pellets. Okay, that opens about 10 worm cans, right there:
What constitutes “an application of oil”? (I have seen paragraphs of instructions telling you how to know if the application of oil has been enough or if you need more.)
Am I testing this on lightweight pellets? Heavy pellets?
Do I test a powerful springer as well as a lower-powered springer?
Do I also test this on a precharged pneumatic?
A powerful PCP and a lower-powered PCP?
What about testing on a CO2 gun?
And on and on….
I think the best approach is to ask the question: Why do we oil pellets and who does it? We know that people who wash pellets also oil them, and we know that PCP users oil them; so that includes all the categories above. I don’t see a need to go to the extremes with this test. I’m not HP White Labs, and this isn’t a burning consumer question. If the findings suggest further testing, I could decide at that point?
What about the possible side effects?
Will oiling a pellet cause extra dieseling? Maybe. Is that what’s behind those flimflam salesmen who claim that oiled pellets go faster than dry pellets? I don’t know for certain; but as long as I’m going down the path, this is something I want to look at. Obviously, we’re talking only about powerful spring guns.
Does oiling affect accuracy?
I don’t know, but it seems we ought to find out. This gives me another excuse to unlimber my R8…so, hurrah!
Have I forgotten anything?
You tell me if I’ve overlooked any test that ought to be conducted. This isn’t a guessing game or a creativity contest, so please tell me only things that really matter to you.