by B.B. Pelletier
This subject came up as the result of a comment I made about choked and tapered bores. It turns out that gun makers were having this same discussion 140 years ago with pretty much the same results.
The best gun makers of the 1860-1910 timeframe (and Harry Pope for just a little longer) all either taper-bored their barrels or choke-bored them. I will describe each of these conditions in a moment. There really isn’t much difference between choke-boring and taper-boring, but the slight difference that does exist allows us to talk about each of them as a separate issue.
Most gun makers (or barrel-makers, because in many cases — like Pope, a man did not make the entire gun) did taper-bore their barrels. But that wasn’t what they called it, so the fact that they did it got lost because of the subtleties of the language.
What is a tapered bore?
A tapered bore is exactly what the title implies. The diameter of the bore gradually tapers down from breech to muzzle. The amount of the taper is slight — perhaps one-thousandth to as much as two-thousandths of an inch; but at the time this service was performed, the measuring tools needed to accurately measure it weren’t commonly available. So, most of the makers didn’t actually know how much they were tapering their bores — just the fact that they were.
What does this do?
Why taper the bore at all? Because there are advantages — the primary one being an increase in accuracy. The reasons for this increase are less obvious and not entirely understood — or perhaps I should say they’re not entirely agreed upon. We know taper-boring works, but exactly why remains something of a mystery.
One thing that we do know is that when the barrel squeezes the bullet down smaller, it prevents gas blowby, which is damaging to the bullet because it erodes the sides and unbalances it. But in guns that use black powder for the propellant, the hammer blow of the exploding powder actually squashes the base of the bullet outward to make firm contact with the sides of the bore. This is called obturation. A black powder rifle doesn’t need a choked bore to prevent gas blowby, because obturation already addresses it — as long as the bullet is fitted closely enough to the bore to begin with.
So tapering the bore must do something else, because it works for black powder arms just as it works for those guns that use smokeless powder that does not obturate the bullet. The theory that I believe is that a tapered bore grabs the projectile more firmly just before it exits the barrel. It stops any unwanted vibrations and sends the bullet on its way with no instability. It ends any side-to-side play the bullet might have inside the barrel. Just because the base of the bullet has been squashed larger by the force of the exploding gunpowder doesn’t mean that the entire length of the bullet is equally in contact with the bore; but if the bore narrows down enough, there will be no doubt about it.
How they did it
Now that you know what a tapered bore is, let’s find out how the barrel makers managed to do it. Actually, the process is simple. If you read how gun barrels were made back in 1840-1910, you’ll see that they did it as a matter of course. They called it “leading the bore” and by that they did not mean lapping the bore, which is a similar but separate step that some but not all barrel makers did.
When they “leaded the bore,” a bore-cast lead slug that was charged with emory was passed back and forth through the just-rifled bore until it had removed a tiny bit of metal from the inside. To do this, they first inserted a long bore-fitting wooden dowel down the barrel. The front section was turned down much smaller than the bore.
The rod was entered from the breech and positioned with its end flush at the muzzle. The barrel was next heated until it was hot to the touch, then molten lead was poured down the muzzle until it pooled up flush with the muzzle. The lead was stopped from going down the bore by the bore-sized wooden rod that was not turned down, and it attached itself to the smaller diameter portion of the rod near the muzzle. When the barrel cooled down, the rod was pushed out the muzzle and the lead mass that was on the end was removed. It was then trued up at both ends, and the wooden rod was pushed out, leaving about a 1/4-inch hole down the center of the plug. A small groove was cut in the lead cylinder, then the cylinder was screwed onto a tool-steel rod that was called the leading rod. The lead plug was then rolled on a steel plate that had emory powder spread upon it. The leading rod was free to turn in its handle, so the lead plug could follow the pattern of the rifling.
The leading bolt after cleanup looks like this. It’s then screwed onto a tool steel rod that works it inside the bore. Image copied from “The Muzzle-Loading Cap Lock Rifle” by Ned H. Roberts, copyright 1952.
At this point, the inside of the bore received a light coat of fine oil, such as sperm whale oil. The emory-charged rod with its lead slug was then carefully inserted at the breech, making sure to engage the rifling exactly. The rod was then moved back and forth from the breech to within about three inches of the muzzle. By concentrating on the rear of the barrel and only going forward a relatively few times, they controlled the amount of metal that was being removed from each part of the bore.
Occasionally, the rod was partially withdrawn at the breech but never again fully removed. When it was exposed in part at the breech, more emory powder could be applied along with a little more oil. By never completely removing it, the lead slug always remained in the proper engagement with the rifling. When the lead slug wore down, the tool steel rod was screwed into it more, forcing the sides back out and into the bore of the rifle.
The rod was worked back and forth, with more time given to the portion closer to the breech and less as the lead slug approached the final three inches of the barrel. How long this procedure took varied with each maker, and probably with the type of material they were working with — i.e., soft iron, cast steel, compressed steel, etc. Undoubtedly, the exact process was a closely-guarded secret for each maker. But it did work, and what they got was a bore with a gradual taper from breech to a point about three inches from the muzzle. Since they never went past that point, that section of the bore remained a true cylinder and was the tightest point in the barrel. It was the choke point.
Since these are muzzle-loading arms and the muzzle is also the tightest point of the barrel, some of you may be wondering if the bullet wouldn’t squeeze down when it was initially loaded and then lose contact with the bore after passing the choke point. That’s exactly what happened, and it made the rifle much easier to load!
Remember obturation? When the black powder exploded, the bullet was upset by the force and enlarged to grab the bore tightly. TWhen it encountered the choke point, everything happened just as I’ve described above. This gave the bullet remarkable stability that had not been seen previously.
Many riflemen were no longer using patched round balls when this style of rifling came into vogue. They were starting to experiment with conical bullets, first with the sugar-loaf or picket-style, then later with the longer, heavier cylindro-conical shape.
The picket bullet or sugar loaf bullet (left) was an early first replacement for the round ball in rifled guns. It has a very short bearing surface that makes it easier to load, but also makes it susceptible to tipping inside the bore. It more than doubled the accurate range of the rifle but required extreme care when loading. The cylindro-conical bullet on the right has more bearing surface but also needs to be driven much faster to stabilize when fired from a barrel of a given twist.
There’s much more, but not now
Bullet shapes of the late 1800s are a fascinating study. For instance, were you aware that some expert riflemen favored a hollow-based cylindro-conical bullet as the most accurate type? For now, let’s leave the world of firearms and return to airguns because choking has a definite place there, as well.
The choked bore
I haven’t described the difference between a tapered bore and a choked bore, so here we go. A choked bore is really just a tapered bore with a short taper. In other words, the bore is parallel from the breech to the choke, and then in a short distance of less than a half-inch the bore tapers down to a smaller diameter that stays parallel until the muzzle. In firearms, this distance for the choked part of the barrel was about three inches, but in airguns it’s more like two.
Intentional versus random and accidental chokes
The only intentionally choked airgun barrels I know of are made for pneumatic guns. Let’s examine why. The pneumatic is much like the firearm that uses modern gunpowder. Instead of a sudden, violent explosion, smokeless gunpowder burns at a reserved rate of speed. When confined, this rate is extremely fast, but it still cannot be called an explosion. So, modern smokeless gunpowder does not deliver the same hammer blow that obturates bullets. Nor do pneumatic guns blast out pellet skirts into the walls of the bore, which is very similar to obturation in the airgun world.
Pneumatic guns release their air at a restrained rate that, while it sounds sudden to us, is really measured in milliseconds. A lot of air is released when a pneumatic gun fires; and though the pressure in the barrel continues to decline as the pellet moves down the bore, this pressure is still enough to provide continued acceleration all the way to the muzzle.
Because the air pressure is restrained in a pneumatic, the pellet skirt is not enlarged and pushed into the wall of the bore. But in a spring gun, it is. A springer releases just a tiny bit of highly compressed air in an instant. This rapid burst of pressure is enough to swell the skirts of some pellets, making them have better contact with the bore.
So, to better stabilize pellets in pneumatics and remove any variations they might have, a choked bore is ideal. Therefore, all of the finer precharged, single-stroke and multi-pump airguns have choked bores. You can feel this if you push a pellet from the breech to the muzzle with a cleaning rod. The pellet will encounter resistance about two inches from the muzzle.
But spring guns don’t need a choke, since the act of firing swells the pellet skirts. However, some spring guns do have the same resistance near the muzzle that is felt in better pneumatics. This is an accident of swaging-in the dovetails for the front sight attachment. Weihrauch guns that have front dovetails all have this and we have called it a choked bore. It’s really just an accident of the manufacturing process and is as random as can be. But it’s there and some shooters feel it helps accuracy. Even though the choke doesn’t wrap all the way around the bore, they feel that it still provides the same stability that an intentionally-choked bore does.
Here is the lesson
The point is, if a barrel is choked, is it more accurate? The evidence suggests that it is. If that is true, can a choke be added after barrel manufacture? The answer is yes! In fact this may prove to be the most cost-effective aftermarket adjustment that can be made to an airgun.
A choke can be added by rolling the barrel between three precision hardened-steel rollers, one of which is adjustable. By gradually increasing the pressure on the adjustable roller as the barrel is rotated between the three rollers, some compression of the steel is possible. This will affect the inside of the bore, reducing it in size. The worker would have to proceed slowly and watch the progress of the choke, because we are faced with the same problem that the 19th century barrel makers had — namely barrels made from different materials.
This device allows the controlled swaging of a round barrel. The adjustable roller located at 4 o’clock is gradually adjusted inward as the rifled barrel turns.
What we have learned today is that airguns and firearms are very much alike in how their barrels can be made to increase accuracy. I haven’t addressed modern firearms shooting jacketed bullets because they do not respond the same as lead bullets. So in this respect, airguns and black powder arms are the most similar.
Excellent. This is why I keep coming back here.
I remember the Daisy 717, 747, 777 series of pistols. One of them, probably the rather expensive 777, was advertised as having a choked bore.
Also, in my pellet experiments, I noticed that in putting a pellet into a .22 chamber followed by primed .22 brass, since the pellet is kind of loose in the chamber/barrel, it doesn’t develop much velocity. When I patched the pellet, there would be enough drag for the gases to get a chance to force the skirt of the pellet against the sides of the chamber/barrel and the velocity was markedly higher. Plus accuracy is much better.
I always thought Weihrauch guns were intentionally choked. What a nice article. Makes me wonder if I would be able to choke my diana 38 and if it would really make a big difference.
I wonder how many very nice air rifles are about the get messed up?
Well it is good to keep this in perspective . A HW or Lothar Walther barrel is not the same as a $12 barrel for a Quest. I think that if a person wanted to experiment it wouldn’t be a bad thing. You could waste a couple dollars on other shooting stuff and not learn as much.
Robert,
I have plans to do just that.
B.B.
I should stay out of this one for now. Too early. Maybe later after I get woke up better and have a few beers. I think better that way.
twotalon
TT
My thoughts exactly. After a hard nights work my first reaction for any problem is “off with their heads!” With a few malted beverages and some time to cool down (after work), I can begin to ponder the situation from a more objective perspective. This has kept me from blowing my top, and perhaps my career. It pays to step away for a moment and see the forest, instead of the Charlie Brown Christmas trees.
As the best American who has ever lived, Benjamin Franklin once said, “Beer is proof that God loves us, and wants us to be happy.”
My basis for my analysis for Benjamin Franklin as the best American who has ever lived, is that among his many inventions, he never patented any of them. He wanted mankind to benefit from his labors, without regard for further financial benefit.
His face adorns the $100 dollar bill, yet he was never President. (Nor was Hamilton on the $10 bill)
twotalon sez: “Maybe later after I get woke up better and have a few beers. I think better that way.”
A shot of Cognac or Bourbon in my coffee works wonders for me. ;o)
An interesting co-incidence.
Just the other night I was reading about a light German anti tank gun from around 1938.
It used what was called a ‘squeeze bore’. 28mm at the breech down to 20mm at the muzzle…a pretty substantial ‘squeeze’.
What it meant was that a tungsten round that normally would have exited the muzzle at around 2000 fps instead sizzled at nearly 5000 fps.
The Germans however started to run short of tungsten around 1941 and couldn’t develop larger sizes.
By 1941 allied armor was thick enough to stop the smaller round.
CSD,
That is a heck of a squeeze! I bet the pressures inside that barrel were phenomenal.
B.B.
Yup…the article stated that barrel life was at the very best, 500 rounds and that they often replaced barrels at around 250.
CSD,
That is about in the ballpark. The estimated barrel life of an M106 cannon on an M60A3 tank is 400 EFC rounds. EFC stands for equivalent full charge, and the hyper-velocity sabot round we shoot that goes faster than a mile a second (at the muzzle) has an EFC rating of one. All other ammunition has a fractional EFC rating, so the barrel lasts longer when slower rounds are used. But we had to borescope and also measure the inside diameter of those guns frequently, to make sure they had not reached the condemnation stage. We shot them a LOT in Germany.
B.B.
Cowboystar dad,
They called it Puppchen – Puppy. It used conical barrel and special “pagoda” rounds with cup-like leading belts. A very interesting gun, but not very effective for German economy – on average anti-tank gun makes less than 50 aimed shots. Typical overcomplicated but beautifully executed German stuff.
I would have invested more in shaped-charge spin-stabilized projectiles – a cross between their R4M and Panzerfaust or just copy more conventional Soviet 57-mm high-speed ZiS-2 antitank gun with its УБР-271П heavy ceramic core subcaliber round. Light, quite mobile, very low profile, more than enough even for Tiger-I @ 1000 m side and straight through glacis plate @500 or 82mm of armor sloped @ 60 deg angle.
duskwight
What an amazing blog…starts of with choked airgun barrels and ends up at German anti-tank guns.
Really…it just don’t get any better!!
cowboystar dad
Well, I scratched my head a bit more and I remembered that late-production sPzB-41 got chromed barrels, so their service life was extended up to 1000 shots, but then again – it was nice, but almost useless against new Soviet tanks. However being forced to choose between this one and nothing – I would choose this one. Or just surrender to Soviets to get a meal and a free trip to Russia. In 1944-45 that was definitely a better option for survival.
duskwight
duskwight,
Ahhh, I’m going to have to disagree with that translation.
“Puppa” is the German word for “doll.” “Püppchen” would be the diminutive form of that word. My parents were German (and lived most of their lives outside Berlin), and my nickname most of my youth and even into my early 20s was “Püppchen.” Since I was born in China, my mother often told people I was her little China doll. Well, it was cute 60+ years ago 🙂
Edith
Edith,
I’m sorry, you’re right – it’s “Doll”. German is not my forte at 1 A.M. Moscow 🙂
What IS worse – I’ve mistaken “Puppchen” rocket grenade launcher with “2,8 cm schwere Panzerbüchse 41” – now THAT is the correct name for that 28/20 antitank rifle and pup is “Welpe”, that’s the correct informal name for it. Dang, I seem to need some Ballistol for my memory.
duskwight
duskwight,
Hey — don’t beat yourself up! According to Edith, I can’t even speak one language right, and she is a German who was born in Shanghai!
I think you’re doing pretty good. 🙂
B.B.
Aha, another cross over between firearms/blackpowder and airguns. Great read.
kevin
Kevin , I was thinking the same thing but after some of yesterday’s comments on the off topic firearms talk, I wasn’t sure I should say anything. I know a little about firearms, but lately I’ve been thinking that I shouldn’t say so much about them here anymore.
Robert from Arcade,
I know that we’ve lost some people because of the off-topic talk, but we’ve gained a whole bunch of new ones. While I wish the ones who’ve left hadn’t done so, everyone is free to come & go as they see fit.
While some people want only airgun talk, we have found that we can’t avoid talking about other things because we do not live on an airgun island 🙂 We live in a world with overlapping areas of information.
There’s much to learn from those who laid the groundwork, and we’d be foolish to ignore it, leave it alone or limit our interest in something that can teach us so much.
We’re seeking enlightenment about airguns…and firearms heighten our understanding of the subject.
Edith
Yes, here you go, case in point relevant to yesterdays OT firearms discussion. How could this blog article be explained as well without reference to firearms?! Good example BB, and an excellent, well presented to be easily understood one as well.
Chuck,
I think when I say I’d like to write more about firearms, some readers are concerned that the blog will wander off into an unrelated realm and I’ll start testing ARs and Glocks, or something. All I really want to do is talk about ACCURACY, but why stick my head in the sand when I know the firearms world has addressed the same things we are pondering and found out decades ago what does and doesn’t work?
B.B.
Please, let’s stay away from AR’s and Glocks!
Robert from Arcade,
Please read very carefully what I’m about to write.
I believe that the parallels of firearms and airguns are numerous. Intertwined. I’m constantly amazed at the “new” technology that is passed off to airgunners in marketing. All we have do to is look at our firearm roots to discover if this “new” technology has a chance to revolutionize airgunning.
Your sharing of information is obviously from first hand experience, my favorite, and of utmost importance to those of us that shoot. I’m one of the most vocal here but have to believe that your words of wisdom are also benefiting many that lurk. Please don’t stop and please don’t feel that you have to limit your comments because they’re very informative for those of us that are passionate about this vocation.
kevin
Robert from Arcade,
Suspect my lengthy post to you got caught by the spam filter.
Short version.
Please keep posting your expanded version of comments. Whether they’re firearm or airgun rooted I’m here because of posters like you that speak from firsthand experience vs. hypothetical. Hope you stick around a long time an keep sharing the gems of information that you have on pesting, hunting, trapping, shooting, reloading, books in your library etc.
kevin
I wasn’t going to go away, but felt that maybe I have been too off-topic with my posts, and perhaps overstepping some boundaries. I like this blog because it has an easy flow to it, with no body getting too wound up. Ideas get kicked around and stuff gets reviewed. Also, you are right about marketing re-inventing the wheel, but everyone has to (should) bump their heads a little along the way.
Robert,
You are not too off topic.
We’ll just keep on doing what we’ve been doing all along.
I think it’s a great blend! Pyramyd AIR is happy with the blog and has no complaints.
Edith
BB,
Thanks for the differentiation on tapered vs. choked.
Edith,
Thanks for that reminder on why spouses may not like airguns. I’m happy to report some progress on that front. I thought the noise was the biggest issue, confirmed when I started shooting my new Discovery in the basement. I needed to find a way to tone it down a lot, so I rolled up an old, wall hanger rug and hung it from the ceiling so that I can put the muzzle in and still sight my target when I shoot. I came upstairs and asked how the noise was and she said, “What noise?” !!! 🙂 It takes care of the sound of the report and I can shoot any of my guns through it!! In the house!! 😀
Thanks!
/Dave
/Dave,
Great news! I love it when things work out well.
Edith
I don’t know why I didn’t think of that sooner. I guess I just needed a gentle nudge back on track! I’ve read enough about sniping techniques and this trick never occurred to me (maybe because I was thinking shrouds and not enough on fixtures…).
/Dave,
You know there are gun ranges where shooters shoot through long rows of tires that are arranged so all the muzzle blast is contained inside. A large-caliber centerfire is quieted very much by such an extreme fixture. If I had land upon which I could shoot safely I would have such an arrangement.
B.B.
hehe I live on land on which this was done for years.
One of the various berms around here is the backstop or what was behind the backstop, so there’s theoretically a lot of lead and copper in there. Prolly ought to dig it out sometime.
flobert,
That is a veritable goldmine! You don’t know how jealous I am. I hope you cast bullets.
B.B.
This place is a junkyard! The family who owned it for 100 or so years, ended up with 3 sons who were junkmeisters, there were many Dumpsters of stuff taken out. It was even *more* of a junkyard then. When I moved here I added 100lbs or so of lead, wheel weights etc to add to the pile lol. The Mysterious Berm Full O’Lead(tm) hasn’t even been delved into yet. I’m gradually growing into this place, getting comfortable with the idea of choppin’ down trees, doing stuff that would get me jailed if I lived in the apartment complexes and rented houses of the past. Wait’ll I learn to repair/maintain and drive the tractor! And the backhoe, the WWII tank mover, the …. we have big machines here for big fun, but also ….. problems it takes an army of Egyptians or big machines to solve lol.
In a way, I live like many did 100 years ago. Farm kids used to do all kinds of stuff (and read up on it; farmers have their 11 and 12 year old daughters driving $100,000 combines even today) for Christ’s sake they used to build AIRPLANES from kits and fly ’em to school! It’s pretty amazing after living in apartments and being in fear of breaking one twig on their pathetic little decorative trees.
Looks like I’ve got a nice little 10m shooting area, well, I could have any number of ’em here but it’s right by my living trailer, and the backstop is the hunks ‘o’ elm I have my officer trailer supported by, if I step back a bit, I can shoot rested against a set of steps going up to the back of a semi-trailer we have here, for testing at the 14meter/yard distance someone here does. That can be useful for resting shooting for finding the most accurate pellet in my Daisy 880, the 10m distance for my pellet experiments with the Single-Six.
We’ve got dove, quail, turkey, pheasant, I saw a coyote once 🙁 and a flock of sheep that are our neighbor’s and graze here when the grass is up. Plus we’re gonna get a few sheep of our own, they’re funny; scared of you one time, the other time jostling you because they think the box you’re carrying is food. I have to learn all about ’em, and one thing I know: If the ram rams me, I’m gonna flip the bugger and then I’m gonna RIDE ‘im! Actually the ram the neighbor has is mellow, lol. We had geese, but they were a big noisy PITA. Their eggs are big enough that you really have to like eggs to eat a one-egg omelet, and they’re natural bullies and that means they’re bit fat wusses with a creamy wuss center. One of ’em was being so mean to one of the others one day, I chased him around and waled on him with a board LOL. Damn bullies!
The rural life: I highly recommend it!
/Dave,
Now, that is what we like to hear!
Congratulations!
B.B.
BB,
I love this kind of article! It not only covers a highly esoteric subject, but illustrates another overlap of PB and air guns.
This type of article may not help our shooting skills, but it really adds to the enjoyment of the hobby by enhancing our understanding of the mechanics involved.
I wouldn’t mind at all seeing an article a week of this nature. Keep up the good work!
Les
Les,
This article is what I was talking about when I made references the other day to articles with firearms in them. You see, there is so much that does cross over from firearms that I’m afraid we are constantly reinventing the wheel as we experiment.
I had this one bubbling up inside me for weeks and today it just had to come out.
B.B.
The drawings are awesome!
flobert,
When we upgraded my operating system last month I lost some very important software. Among what is gone was my draw program. It was only Corel Draw, which is a hinky program, but it worked for what I needed. Now I have nothing, so those were freehand with a pencil. I thought they looked very crude, but I had to convey what I was saying some way.
We are going to get another program that will work with my new operating system.
B.B.
I actually mean it non-snarkily, the drawings kick ass. They do so because they’re genuine. They are drawn from the heart. I love drawings like that.
Now this is very interesting. As for why a tapered barrel should affect the accuracy of even blackpowder, I think this pulls together some different threads. If it’s true that accuracy is greatly determined by the fit of the round in the chamber (headspacing), then everything else in the shooting cycle (like the barrel) acts to minimize the losses to this perfect fit. Jeff Cooper uses the term “range-probable error” for all the little effects which make a projectile inaccurate over larger distances. But perhaps this effect also applies even within a barrel. So the tapered barrel serves to compensate for “range-probable” error even on the scale of inches….
HankMcCrae, I don’t have exact records, but I must be close to 70,000 rounds for my IZH 61. Actually Mike Melick wondered if the barrel might be shot out. But I was going with B.B.’s opinion that spring guns can last for centuries. And sure enough, once Mike lubed and tuned the gun it was just as good as ever.
B.B. good to know about the recoil springs. I was thinking myself of a lighter weight spring for the lower weight bullets in my 1911 since I’m told the spring is unusually stiff.
Mike, I’m sure you’re right about not needing to weigh the powder so precisely. But my firearms shooting is very limited anyway, so I thought I would take the extra precision on as a challenge. It’s actually almost as much fun as hitting a bullseye.
Victor, interesting about how one becomes a shooting master. Clint Fowler told me that becoming a master was not something that necessarily happened because it was in your game plan. And there may be truth to that, but one doesn’t want to discount sheer willpower. As Henry David Thoreau said, “You never hit something unless you aim at it, so you may as well aim high.” And said in a shooting metaphor no less….
/Dave, outstanding video of the motorcyclist and worthy of dissemination. Thanks. That guy is a true Jedi. As with watching boxing matches and mixed martial arts competitions, I don’t approve but if someone is willing to be that stupid I may as well learning something from it.
Matt61
Matt61,
Thanks for your reply. All I can say is wow… Ok, I’ve gathered myself. I think it was Famed tuner Tim McMurray that once said springers are either braking or they’re broke. Maybe he never met the pesky little IZH. Please write a guest blog on that rifle, that would be a great read.
-HM
Matt,
One of Harry Popes guns — one he personally used — had over 120,000 shots on it and showed less than one-thousandth inch wear in the bore. And this was a rifle that was muzzle-loaded, so there was a wooden rod down the barrel on every shot.
An airgun barrel simply never wears out. I suppose in something approaching 100,000 000 shots it might be possible, but there are club target rifles with several million shots on them and they are still shooting well. Though they are not rifles, the U.S. Arms got 10 million to 20 million shots from many of their Quick Kill BB guns. The mainsprings and seals had to be changed, but never the shot tubes.
As for the spring in your 1911, a 16-18 lb. spring is normally recommended for hardball ammo. That’s 230-grain FMJ stuff. The target semi-wadcutters use a 12-lb spring. And for +P loads a 21-lb. spring is available.
B.B.
BB,
It’d sure be silly to ignore hundreds of years of firearms reach into barrels.
Was there a firearm barrel like the “new” smooth-twist airgun barrel?
Regards,
Herb
Ugh…
“research” into barrels…. not “reach”
Herb,
As far as I know, the smooth twist is a new concept. It follows the hammer-forging process that has only become popular since the end of WW II. So that one is really new, unless there is something I don’t know.
B.B.
I like to justify firearm reference like this:Try to imagine where airguns would ACTUALLY be developement-wise WITHOUT the tremendous benefit of firearm developement knowledge to draw on as a resource! So very little of the total technology (and manufacturing practices)utilized today is exclusive to airguns.
On an unrelated note,my JW80 really likes to be shot with the .20 barrel I just recieved! I just chronied it with 1993 vintage Crosman Premiers (boxed) lightly lubed with Whiscombe honey:first shot 900.2fps,ten shots yeilded a spread of 11fps and the SD was under 4 fps.The seller of the barrel actually included this full box of 14.3gr 1993 CPs as a nice Christmas present.The first casual 5 shot group was @21yds and .21 ” ctc.Considering that was standing,braced by the door frame……no way will I change the HOTS setting(at least till I scribe a mark on the weight) because it is clearly right where John Whiscombe set it!
Frank,
Isn’t it wonderful when something works even better than advertised? What a nice gift those pellet were!
B.B.
A truly wonderful gift indeed! I am quite hesitant to run the new CPs through it,for fear of what I’ll find regarding groups……but I’m doing the prerequisite documenting anyway.Even with a Whizzer that takes 3 strokes to cock,600 pellets goes by quick when they go right where the crosshair says they will.I’m a very happy camper (again) today! 900fps is such a nice,promising number too.
B.B.
That’s a wonderful article. I remember to spend a week to find all the info you have summarized in this 15-minute reading. And this 3-roller device – I remember it 😉
For “unintentional” choke I must tell that sometimes on cheap Izh airguns treads on the muzzle end are cut so violently, that barrel becomes somewhat “choked”. As this choke is uneven, best cure looks like a fine saw and a set of tools for recrown job.
I myself prefer cylinders, they seem to be of no difference to choked ones on springers. I am too much “springer man” to speak for the other types. In my experience choked barrels seem to be more demanding on the crown job – don’t know if it is true, but it feels that way.
I wonder if a PCP perfect barrel would be tapered with progressive rifling – well, I don’t know who makes them to test one 🙂
duskwight
duskwight,
I picture myself trying to lead a .177 bore with a rod as I described it in the report. Must be a better way of getting into the nut house!
B.B.
Does anyone have the link to that simulator that illustrates the effects of canting?
Thanks,
Victor
This what you’re looking for:
http://www.eatel.net/~stentorian/targetplottrajectory3.swf
Cowboystar Dad,
That’s a good one too! I was referring to
http://www.arld1.com/images/swfs/impactpointvscantangle.swf
Thanks,
Victor
No worries. I found it.
Re: Cant
Here is one…
http://www.arld1.com/impactpointvscantangle.html
But remember that this demo would be mostly true for PCP at one distance. For a springer cant could change the harmonics too and the pellet could go anywhere.
Also there is a distance factor here. So if you zero at one distance with no cant, then shoot at a different distance with cant the pellet can move in ways not show on the above demo.
Hope this helps,
Herb
RE: HOTS on a Whiscombe
Curious… How much could you move the pellet around by changing the HOTS setting?
I played around with a heavy doughnut weight hung on the end of a cheap Crosman G1 break-barrel and it moved the POI down 3-4 inches over 10 yards. I assume that was because of the slop in locking the barrel in position rather than harmonics. I was trying to see if the extra weight make the rifle group better and it didn’t.
Regards,
Herb
I have a pair of HW50’s – the older ones that had machined front site grooves and therefore no choke – that would be ideal for a choke – no choke shoot off.
Why? When Mr. Watts tuned one of the rifles, he actually made a point to give me a call and ask if I wanted him to choke the barrel. His explanation was that it would be accurate with a wider range of pellets. The other rifle had the barrel chopped by Rich in Mich, so if by any small chance a choke did exist – it got whacked off.
Both guns shoot with-in about 10 fps of each other.
The bad news is with the crappy weather here, it will be a good bit of time before I can compare them out doors at 30 yards plus to see if their is an appreciable difference.
Slinging Lead,
I had a request that you finish the Disco post….you have a fan!
Kevin,
I saw you scored an HW50M – did you get it yet?
Volvo,
Yes, received it about a week ago. It was mostly as described. Great metal. The minor scratches on the stock won’t be a problem if I can find time to work on the stock. Funny how a gun can lose 150fps while being shipped about 800 miles LOL.
My primary interest in the gun was its transition stock. This was the “M” stock that Beeman marketed after the weihrauch finger groove but prior to the full fledged goudy. Interesting. The other attraction for me was that this gun was manufactured in 1976. Important year for me. Not sure anyone else gives a hoot.
I’m going to send this one off to paul for some work. Not sure why I’m accumulating so many of the weihrauch 50/55 series guns but I really enjoy these.
kevin
Kevin,
Rumor has it, their were only 40 of those Italian made stocks left that Beeman bought up for their M model.
The “M” designation is confusing however, since HW used that to designate the models with perfekt triggers and Beeman decided it would mean “Monte Carlo.”
How do like the stock compared to the R8?
If you would have waited a bit, I might of had one for you. : )
Matt61,
M1 carbine better than a Mini14?
You made me spit my beer out.
Did you ever shoot a newer Mini 14?
Great bang for the buck, like most Rugers.
I’m a confirmed Ruger loyalist and the Mini-14 has come a ways, apparently the earlier ones were very inaccurate. I have one of the earlier ones. Strictly “Charlie’s on the wire” duty.
Just shows how hard it is to change an image, the new ones are just fine accuracy wise. They will also handle 5.56 surplus along with .223 ( other than the target version – .223 only ) another common misconception.
Plus you can get 20 or 30 round factory magazines…some people still hold it against Bill for say 10 rounds was enough….
duskwight,
In that motorcycle video, I thought parts of Varshavskoye Shosse looked familiar. I just looked it up on the map and found out why. About 11 years ago, I used to teach at the English Language Center when it was just across and down the street from Stansiya Nagatinskaya. Down Nagatinskaya Ulitsa about a half a kilometer at a high school. I crossed that street many times coming from the Metro and actually almost got run over there. How far out of town on M2 is that range, or is it an indoor range in town?
/Dave
Dave,
In town, a little bit closer to Tulskaya, behind the “Trud” stadium.
duskwight
I have never heard of “taper choking” in a rifle but I have in a shotgun. As a way of qualifying what I say, I am 74 years old. My father used to tell me about taper choked barrels on shotguns. He said that all good shotguns were taper choked. He preferred Hopkins & Allen single barreled shotguns because of this feature in them. Surprisingly, taper choked shotguns shoot smoother than muzzle choking (a few inches choked from the muzzle).
Now, I have owned many shotguns in my lifetime, mostly Remington. All of the guns that I owned had the choke stamped on the barrel. I despise the “screw in” chokes.
Jerry,
Welcome to the blog!
I hope you will become a regular reader.
B.B.
BB mentioned the only choked airgun barrels he was aware of are pneumatics, but I’ve had Feinwerkbau, Weihrauch and Diana springers that were choked. The oldest of those was circa ’82 or earlier. Imo choked is the only way to fly with an airgun. It not only makes it more accurate, assuming the choke and bore is quality, but it makes the gun shoot a much wider variety of pellets accurately. I seems obvious to me this is because it swages all the pellets down making them a perfect fit. I’d imagine it makes their BC better too, both smaller dia and less of an edge at the head. A typical bore to pellet fit is often questionable so you have to try many pellets to find one that works best, sometimes even buying oversize pellets to make that happen.
Aside from the quality, Lothar-Walther airgun barrels are also choked, so if you buy a blank be sure to cut it to fit from the breech end!
A friend also has a 22LR with a choke, which is drool worthy accurate.
Thank heaven I found this info,,,the digging was worth it. I would like to try a “choked” barrel on my Daisy 25. Seems this tooling maybe available?
Can a relevant “magnetic” choke be placed on a BB barrel? Or maybe better said, will a magnet placed anyplace on a barrel create a good or bad effect?
Plinkerton Det.,
Never heard of one. Why don’t you try it and see?
B.B.
Living up to my name, and I haven’t found any effect from up to 10 small but very strong magnets being place at various places(other than feed problems). I wonder if a stainless steel barrel would be any different. I suppose they have to have some change,,,,on the way to manufacturing a rail gun.
Plinkerton Det.,
I have done magnets (very strong ones) on a Avanti 499. Easy to do with the way the barrel comes out. I can not really say it helped anything as I recall. The idea for me was to get a “hop-up effect” = airsoft and paintball lingo. The idea is to impart a back spin.
The 499 is very accurate, so is it is tuff to see improvement. I even put them in a spiral pattern. Plus, feed issues like you said since it is a muzzle loader.
Check this out since you like playing with the small lever actions. These guys do anything and everything to them including custom made parts.
https://www.thehighroad.org/index.php?threads/putting-a-little-more-power-in-a-15-00-daisy.807316/page-9
I keep trying those magnets thinking they will have some effect, good or bad. I’m not much of a fan of the lever actions, just the slide model 25, which I am trying to tighten up the pattern. Given a good barrel from what ever source fits in a model 25, the goal is to make it shoot tight. So I would try Lothar Walther for a replacement or maybe fit the barrel from a 499. Anything longer would be ok, with a barrel bushing to lengthen the barrel.
Sight changes I would like to try is a 2+ dioplar lense to replace the front sight, a vented rib, a rail for a red dot, or a neon insert in the front sight. Most all my shooting is at speed.
Thanks for the link to the highroad.
P.D.,
I am sorry. I am not up on my bb guns. I thought the 25 was a lever. I like the way you think. Please (trust me),… when you get the time to look over The High Road link you will be blown away. They do (all) types, including the pumps. If there is something to know or what can be done,… those guys (know) it. It seems like a perfect fit for you with your ideas.
Hope to hear more from you in the future. Keep us posted. Comment on the (current) blog if you want more people to see it and reply. Off current topic is no issue,… it is done ALL the time. 😉
Chris
P.D.,
By the way,… my 499 is set up with a Red Ryder spring and it added 150 fps! It shoots better than,… well let’s just say that it shoots better than the original. I got the tips and idea from a guy that did it that goes by the name of Cobalt. Look him up and tell him I said HI!
That sounds like a great mod! Do you offer a service for this conversion?
A fast shooting 499 with better accuracy and more shots available. What’s not to like, except it isn’t a slide action….:)
P.D.,
It is not hard. There is a few tips though. Like I said,… check out The High Road and ask a few questions and they will keep you busy forever. When it come to bb guns, these guys know them inside and out and even the old ones. With some of your ideas, I think that you would be a perfect fit within the group. At the very least, you can bounce some ideas off of them.
Lense sight from archery bow for front sight
or ATPS if I can find the paint to do it
Such a small post