Category: All About Guns
Categories
Sunday Shoot-a-Round # 348
A pinweel (a perfectly centered shot) is the standard for an airgun target rifle’s accuracy.
This report covers:
- Personal experience
- Why clean?
- Leading
- Burned firearm powder
- Target airguns
- Pope’s barrels
- Time to test
- What about “seasoning” the bore?
- Are four groups enough to know for certain?
This report series addresses a question I have written about many times and wondered about for years but never got off my tush and did anything about. Well now I’m going to!
After the Part 4 test of the AirForce Edge I got this comment from reader billj, “BB,I may be asking about something obvious, but when was the last time that the barrel was cleaned? I only ask because tests in the past have improved greatly with just a barrel clean.Thanks. Bill”
And after the Part 3 test of the new Crosman Challenger reader Tomek wrote,“I’m never quite sure after how many pellets I should clean the barrel of my match rifle. There are slight differences in the shot grouping when testing after a few heavy shooting sessions compared to a clean barrel. Yet, I’ve never been able to determine exactly how significant that difference actually is – grouping vs. amount of shots.”
But then reader edlee said this,“While I am not one to dismiss the experience of others, and I certainly agree with the idea of a thorough initial cleaning of any air gun, It has been my own experience that cleaning (after the initial one) doesn’t affect accuracy for the better.
It may seem counterintuitive to some, but I have spoken to a number of competitive shooters when I was active in the sport. They, and I, found that cleaning often had a detrimental affect that required a great many shots before accuracy was recovered. In fact, most of us never cleaned our rifles more than annually and only if no competitions were in the near future.
In fact, I shot mine for five years without cleaning. I haven’t shot it for seven or eight years but would be willing to bet that it is as accurate today as the day I put it in the back of my safe were I to fire my normal half dozen “warm up” shots (and if I still had the skills needed to do so).”
Personal experience
When I competed in 10-meter air pistol with the National Rifle Association I never cleaned the barrel of my air pistol. I had talked to several competitors of both the rifle and pistol disciplines and none of them ever cleaned their barrels. I believe it was Scott Pilkington who used to support the airguns of our USA Olympic team who told me none of those competitors ever cleaned their barrels. They sent their rifles back to the manufacturer for servicing from time to time and a barrel cleaning was performed as part of the service. I believe I was told it often took as many as 50 shots to settle the airgun back down to be accurate again.
Why clean?
We clean the barrels of guns for many reasons. With black powder firearms, for example, the residue left when the black powder burns is both acidic and hygroscopic and absorbs water from the air. That acidic water then rusts a steel barrel in almost no time. So cleaning those barrels is a big deal and cannot be postponed.
Then there are corrosive primers. They will rust a steel barrel in days, and they have a problem that even black powder does not have. The corrosive primer material can get into microscopic fissures in the barrel steel and even after a cleaning that material can exude out and corrode the barrel. So a second cleaning one or at the most two days after firing is necessary.
Military ammunition often has corrosive primers that the military doesn’t worry about because their people are supposed to keep their weapons spotless. That works in theory but not as well in practice. I have seen several M1911A1 .45 ACP barrels that were totally rusted and shot sparks when they were fired.
Leading
Now let’s talk about leading, which is another way bores get fouled or dirty. The faster bullets/pellets are driven the more they tend to scrape off their material that then bonds to the steel in a barrel. Think of it as soldering to the steel. And bullets/pellets with lead hardened with antimony do this much more than softer lead bullets. Propell them very fast and soon there will be leaded rifling. When that happens accuracy drops off.
Soft lead also scrapes off but not as much as hardened lead. But the faster it’s driven the more it scrapes off.
Burned firearm powder
Then there is the residue left by non-corrosive smokeless firearm powder. This stuff is dirty-LOOKING, but it usually doesn’t have a deleterious effect on barrel steel. So we clean it out and it looks dirty, but not much harm is done if we don’t clean it. Eventually it can cake up and cause slowdowns in semiautomatic and tightly-fitted action parts or tight-fitting revolver parts, so cleaning is necessary—just not as necessary as it is for the former items we discussed.
Target airguns
Target airguns shoot their pellets very slowly. Target air pistols shoot as slowly as 300 f.p.s. and seldom exceed 500 f.p.s. Target air rifles shoot between 400 and 650 f.p.s. At these speeds the soft lead target pellets they shoot shed little lead, if any at all. And target airgun barrels tend to be smooth which also helps them not scrape off lead. So the barrels on target airguns tend to stay clean. For this reason, cleaning them is seldom necessary—if ever. Or so goes the belief.
Pope’s barrels
Harry Pope made some of the most accurate rifle barrels of all time. Nearly all of his guns fired black powder so they had to be cleaned for the reasons already mentioned, but if that was done faithfully there is no reason a Pope barrel shouldn’t be as accurate today as when it was made more than a century ago.
Time to test
I want to test the theory of what cleaning a pellet rifle barrel possibly does to accuracy. I suppose there are many ways to do that and here is what I plan to do. I will take a target air rifle that has demonstrated mediocre accuracy with a certain pellet. When I am fresh in the morning I will shoot four five-shot groups with that pellet at 10 meters.
The AirForce Edge rifle recently put five RWS R10 Match pistol pellets into 0.412-inches / 10.46mm at 10 meters. This is a HUGE group for this rifle! This WAS NOT shot in today’s test.
I will then aggressively clean the barrel with JB Non-Embedding Bore Cleaning Compound and a wire brush. After that I will then wipe out the bore with cleaning patches until they come out clean.
Following the cleaning I will shoot another four five-shot groups with the same pellet and we can compare them to the first four groups.
What about “seasoning” the bore?
In this test I will not season the bore with any shots. I thought about that and decided that “seasoning” by itself becomes a second test that can interfere with the first one. For example—how many shots are enough to season a bore? One person says five and someone else says ten or some other number.
Are four groups enough to know for certain?
I took two semesters of statistics in college, one of them was titled advanced statistics. Of all my subjects these two were the only ones in which I got straight As. I see people all the time who don’t understand the basics of statistics. For example, I see a lot of folks saying that 20 shots is more telling than ten shots. Yes, it is but the AMOUNT of the difference between the two sample sizes is too small to consider.
So—are four 5-shot groups enough to tell us anything? For some they are and for others probably not. In my opinion four 5-shot groups are not conclusive, but they could be indicative.
I expect you readers will have a lot to say about this test, but by the time you say it the test will have been run. Because that will be the next thing I report to you.
