The importance of bullet-to-barrel alignment and fit: Part 1
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Why go to the effort?
- Ten shots in 0.2-inches at 200 yards
- So what?
- Other airgun breeches
- Always liked single shots
I am writing this report for a number of reasons. The main one is because all you readers are interested in accuracy, and today’s topic is an important component of that. Yesterday reader Vana2, who goes by the name Hank, asked me if the Daisy 499 could be converted to a magazine. Here are both his comment and my answer.
Question about feed mechanisms and accuracy on the BB guns…
The 499 billed as the most accurate BB gun and it is a single shot muzzle loader.
Considering that steel BBs are not likely to be deformed in the magazine and they are held in position with a magnet, would there be any technical reason that the 499 could [not] be magazine fed?
Just seems that muzzle loading is a little inconvenient.
Welcome to July… Happy Monday!! 🙂 Hank
That tight barrel is the reason for muzzle loading. Did you know that Harry Pope built his breechloaders to have their bullets muzzle loaded? It was for a different reason, but they were called muzzle loading breechloaders.
That said, I suppose a magazine would be possible. But target arms are typically single shot so I guess Daisy never saw the need.
If I hadn’t argued with them in the 1990s, they wouldn’t have ever sold the 499 to the public. They didn’t think people would pay the price, and were shocked by the response.
When I told him that, I figured it would raise some questions, so today I want to discuss bullet-to-barrel alignment and fit, which in our world is pellet-to-barrel, most of the time.
First — what I said about Harry Pope (considered the world’s most accurate barrel maker for more than a century) is true. He made breechloading rifles whose bullets were loaded from the muzzle and rammed down the barrel to the front of the loaded cartridge that was already in the chamber. This process took longer than simply loading a cartridge, but Pope demonstrated that 100 rounds could be loaded and fired for record in 130 minutes. That seems slow today, but bear in mind that the pace of these contests was not rushed.
If you ordered a Pope muzzle-loading breech loader you got this bullet starter with it — along with a false muzzle, a bullet mold, a bullet lubrication pump and a powder flask. From the book, The Story of Pope’s Barrels, by Ray M. Smith copyright Stackpole, 1960.
Why go to the effort?
Why go to all the effort of doing this when breech loaded cartridges were available? The answer? Accuracy. We still do things like this today. When a field target competitor loads a pellet and then discovers some damage to the skirt, he doesn’t shoot it for record; he blows it off by firing it into the ground, after announcing his intentions. That is the same level of fanaticism that’s found in any target shooting competition.
Ten shots in 0.2-inches at 200 yards
Sometime around the turn of the 20th century Harry Pope shot ten shots with his personal muzzle-loading breech loading .33 caliber rifle at 200 yards that measures 0.20-inches between centers. It stands as the best group ever shot at that distance, but the actual target was blown into a river and never recovered, so it never made it into the record books. Harry Pope measured it when he retrieved the target, before it blew away. He was so respected for his honesty that the group was accepted by shooters, nevertheless.
Yes, that is the trime next to what I believe is the smallest 200-yard 10-shot group ever shot from a conventional rifle. From, The Story of Pope’s Barrels.
There has been no record 10-shot group shot at 200 yards since that time that exceeds this one. The current record was set on July 26, 1999 by Ed Watson, with 10 shots going into 0.245-inches. That was with a heavy barrel rifle. I don’t know if there is an unlimited benchrest group that is smaller, but Pope’s rifle weighed less than 14 pounds, so this record is from a rifle of equivalent construction.
The title of this report is The importance of bullet-to-barrel alignment and fit, so what does muzzle loading the bullet have to do with that? A lot, as it turns out. Pope knew that the base of the bullet was the most critical area because of the gunpowder’s acting on it as the bullet left the muzzle. A breech-loaded bullet has small lead “fins” put there by the rifling as the bullet passes down the bore. Muzzle-loaded bullets have the same fins at the front of the bullet, where they don’t cause inaccuracy problems.
When the bullet starts at the breech, it develops fins of lead at its base from the rifling.
How does this relate to airguns?
It relates in several important ways. First, we know that a pellet that is deliberately (and correctly) loaded into the breech before the shot will almost always be more accurate than one that is blown into the breech from a magazine at firing.
Take 10-meter target pistols for instance. I competed in 10-meter air pistol at the national level a long time with a Chameleon from Aeron. It has two strikes against it. It was CO2 and it blew the pellet into the breech upon firing. It was a single shot, but it was loaded via a swing-out chamber that aligned with the breech like a magazine. I believe my choice of pistol probably cost me 5 points per 600-point match.
My FWB P44, in sharp contrast, is a PCP and has a hollow bolt probe that seats the pellet directly in the breech when the bolt is closed. It may not look like such a big deal, but for ultimate accuracy (and confidence) it makes a big difference.
The FWB P44 bolt probe is positioned to perfectly insert the pellet straight into the breech.
Other airgun breeches
The FWB target pistol breech is not the only airgun breech and bolt probe that’s special. The RAW rifle action has a special bolt that aligns the pellet with the barrel as it inserts it into the rifling. It does a couple other major things, as well, and it’s my personal belief that this bolt one reason why RAW air rifles are at the top of the PCP heap. I will give more detail when I review the RAW rifle.
Always liked single shots
I think most readers know that I prefer single shots over repeaters, and today’s subject explains a big reason why. Is a rifle accurate just because it’s a single shot? Not at all! If you only shoot commercial ammo, a single shot doesn’t give you any advantage over a repeater. But if you reload, a single shot allows you to tailor your ammo so that — wait for it — your bullets are precisely aligned with the barrel! I am one of the few people on earth who shoots an AR-15 single shot, and my AR is quite accurate. Today we have explored half of the reason why.
There is more to this discussion. We have yet to discuss the fit of the bullet to the bore. That comes next.