Monday, August 20, 2007

Bullets and pellets: What gives?

by B.B. Pelleiter

Big post today. We had a question last week that I want to explore. Here it is:

Is it possible to damage a rifled barrel by using pellets that are too large? I'll explain.....
My Condor is a .22, and I have managed to locate some VERY heavy pellets from Daystate (40 grains). I bought and used a few, but on the tin they say .223. They are impossible to push in with your finger alone, and they dont have a skirt, so i actually used the backside of a small metal spoon. This got them in (after a few slips where i bent the pellet around!!!). When fired they leave the barrel at over 900fps, which is actually slower than I expected, and I think this is due to the super tight fit. I have only fired 10 or so this way, as I dont want to ruin the barrel.

Are these safe to fire?

And here was my answer:

Big bullet,

What you have are NOT PELLETS. They are BULLETS!

This is why I rant on about the proper terminology. I'm not chastizing you for not knowing, but whoever (at Daystate) thought that because a projectile is shot from a pellet gun and not a firearm it has to be called a pellet has done a disservice to their potential customers.

Your bullet is actually from an Eley .22 long rifle cartridge that Daystate buys from Eley for one of their rifles that has a .22 rimfire barrel. Pellets don't work in that rifle, so these bullets have to be used.

The bore on a Condor is nominally 0.2165" in diameter, so this 0.223" bullet is way too large for the bore. Only a very powerful gun like the Condor could fire it.

You are not hurting the barrel, unless you screw up the breech with whatever tool you need to push the bullet into the bore. You are sizing the bullet when you shove it into the Condor barrel, and that's why I'm guessing it's leaving a ring of lead at the breech.

You think 900 f.p.s. is SLOW??? Instead you should wonder how the Condor can shoot these bullets at all! You are pushing a .22 caliber bullet through a .21 caliber bore.

Stop using these bullets immediately. They are not accurate and to continue to use them only exposes your rifle to potential damage.

Now, here is today's post.

If you are going to experiment with airguns, you need to get really involved and read about firearms, too. Black powder firearms are especially pertainent, because they share many of the same physical attributes as our airguns. For example, longer barrels get faster velocity with both black power arms and pneumatics. And it never hurts to know something about reloading, either. Just as you should not resize a bullet more than one thousandth of an inch if you want accuracy, you also shouldn't expect accuracy when a huge bullet has to be forced into a smaller barrel like our reader was doing. Once it's in the barrel, the bullet is not too tight to shoot, because lead doesn't expand after being sized down, but when you size a lead bullet six thousandths of an inch or more, there is no hope for accuracy. The axis of the bullet has been changed by the resizing.

They are BULLETS - not PELLETS!
And this is why I get on my high-horse when manufacturers and dealers start referring to solid lead projectiles as pellets. Bullets are solid and have a high ballistic coefficient. They also have a high mass. The longer and heavier they are, in relation to their diameter, the faster the have to be spun to stabilize them. Spin rate is a function of the rifling twist rate and the velocity of the projectile. If a Condor drives a 40-grain bullet at 900 f.p.s., the rotational spin rate is 675 revolutions per second (40,500 RPM). A standard speed .22 long rifle cartridge drives the same bullet at 1,138 f.p.s., producing a spin rate of 853.5 RPS (51,210 RPM) from the same rifling twist. That higher rate is required to stabilize that bullet. The Condor might shoot it accurately enough at 10 and even 25 yards, but by 50 yards the bullet will be scattering.

On the other hand, a 28 grain Eun Jin PELLET driven from a Condor at 1,000 f.p.s. is fully stabilized by BOTH its spin of 750 RPS (45,000 RPM) and the drag created by its hollow tail and wasp waist. The 28-grain pellet is nearly as long as the 40-grain bullet because it is hollow inside, but the aerodynamic drag created by the skirt more than makes up for a slower spin rate.

Bullets are usually not accurate in pellet guns
Because the twist rate of a pellet rifle is so slow (one turn in 16 inches of travel), a solid bullet usually cannot be stabilized properly. There is a firearm equivalent to which we can compare. Aguila, the Mexican ammunition maker, makes a special SSS (Sniper Sub Sonic) bullet for their special silhouette cartridge. It weighs 60 grains and is therefore longer than a 40-grain .22 LR bullet. These cartridges will fit in a rifle chambered for regular .22 long rifle ammunition, but they won't be accurate! At 25 yards you might get them to group, but by 50 yards, they are all over the place. So, why does Aguila make this cartridge?


The difference between an Aguila SSS (right) and a standard 40-grain .22 Long Rifle bullet is obvious and dramatic.


There are special .22 rimfire silhouette rifles that have barrels with a 1 turn in 10-inch twist rate. The normal .22 twist rate is 1 turn in 16 inches. In these faster-twist barrels, the SSS bullet is very accurate and also delivers more of a punch to topple those heavy steel targets. It's not even launched at 1,000 f.p.s., yet it is stabilized by the faster twist. Here is a bullet made for just a single purpose, and it has to be used in a gun built just to handle it. The rifle will not be successful with any other type of .22 rimfire ammo and the bullet cannot be fired in any other gun that is chambered to accept it. Talk about one gun - one bullet!

Well, your pellet rifles are not much different. They will function best with just a few similar pellets. Specialized guns like those from AirForce, some from Air Arms and some from Shin Sung have easily adjustable velocity, so they may be able to handle more types of pellets that fixed-speed guns. But even for them there are limits.

Size matters
Now, there was a huge clue as to the nature of those heavy Daystate "pellets." They said .223" on the tin. And the reader wondered whether that made any difference. Had he known the bore size of his Condor and the fact that bullets cannot be resized that much and still be accurate, he would never have tried them. This is where knowing the technology of firearms and reloading comes into play. I have said more than once in this blog that .22-caliber pellets are not the same size as .22-caliber bullets made for firearms. A .22 pellet bore may not exceed 0.218" in diameter, while .22 firearm bullets come in sizes .223", .224" and .225". GUESS WHAT? You're not supposed to use a .223 bullet in a firearm bored .224, either. You .22 Hornet owners should know what I'm talking about.

Another clue was the fact that he needed a spoon to shove the bullet into the Condor's breech. This is a problem with all bullets in air rifles. They don't chamber easily. Even if bullets are made to the correct bore size, you still have to engrave the rifling along the entire length of the bullet. That takes a lot of force, which is why many muzzle-loading rifles use cloth patches to take the rifling instead of trying to engrave a lead bullet. In the 18th century when the military tried to shoot patchless lead bullets in rifles for the first time, they had to use iron ramrods instead of the traditional wooden ones, because the force needed to engrave the rifling broke wooden ramrods. Introducing an iron ramrod into the bore of a rifle was the kiss of death for accuracy because of the damage it would do to the rifling, but there was no choice. The undersized Minie ball bullet solved that problem in 1840, but by then the days of muzzleloading firearms were almost at an end.

You're on your own
The rate of product development today has outstripped the ability of most companies to keep pace with technical information. Six millimeter plastic balls are now called BBs because of ignorance and a language translation problem, so when potential new shooters go to Wal-Mart to buy airsoft guns for the first time, who will explain to them that Daisy sells tiny steel balls they call BBs and all the airsoft BBs are larger and made of plastic? If we confuse bullets with pellets, then what hope do we have that people will understand that 6mm round plastic balls ARE NOT THE SAME AS STEEL BBs (and will not work in BB guns)?

The world I grew up in demanded that shooters at least tried to understand the technology. But modern information technology has changed all that. People expect to be entertained by the owner's manual, which is why DVDs are packaged with pasta makers. Today's shooter has to find information sources he can trust and shut out the inane jabbering the internet encourages.

30 Comments:

At August 20, 2007 6:37 AM, Anonymous Anonymous said...

Hello BB,

why have all airgun barrels the same twist rate? The slow shooting target guns should profit by a higher twist rate. But maybe at 10 meters they don´t need any rifling at all.
Is there a formula for which velocity is needed to stabilize a certain pellet length?

Markus

 
At August 20, 2007 6:50 AM, Anonymous JP said...

As to terminology use and almost-false-advertising in velocity ratings (that I asked about in another blog), blame it on Lawyers. If we could get them out of the advertising loop, perhaps good products and good information could come to light more often. Very good post BB. JP

 
At August 20, 2007 6:57 AM, Blogger B.B. Pelletier said...

Markus,

The twist rate started with the first modern air rifles in 1906. BSA made them and adopted the twist of the .22 Long Rifle. There are some airguns with slightly slower and slightly faster twists, but most have the standard rate.

Little experimentation has been done, and accuracy is now so good that I doubt anyone feels pushed to do more.

B.B.

 
At August 20, 2007 7:25 AM, Anonymous Anonymous said...

BB

as the original poster of the oversized pellet question, i must thank you for an excellent answer. I am also very annoyed at Daystate for allowing themselves to market the bullets as .22 Pellets. They dont show the packet on the web, so you only get to see the box (where it says .223) once you have bought them mail order, and i bought 6 boxes, each box costing $28 :(

 
At August 20, 2007 7:39 AM, Anonymous Anonymous said...

If you bought them from AoA, which is Daystate's Outlet here in the US, assuming that that is where you are, it is clearly shown that they are .223 under the description. It also clearly says "Bullet" on the Tin.

 
At August 20, 2007 8:06 AM, Blogger B.B. Pelletier said...

Dear bullet owner,

Somebody owns the Daystate Ranger that HAS to use these biullets. Maybe they would buy them from you?

advertise for free here:

http://www.airguns.net/classifieds/classifieds.html

Regarding the lesson - it was cheap. I have paid a lot more to learn less.

B.B.

 
At August 20, 2007 8:38 AM, Anonymous Anonymous said...

BB

maybe at some point ill buy a rifle barrel to put on the condor, as they are easily interchangeable. I am in the UK and i bought the bullets from Daystate directly. Like you say BB, its a lesson learned :)

 
At August 20, 2007 9:09 AM, Anonymous Anonymous said...

BB: just a thought for you. Pulled .22 Bullets can indeed be used successfully in a .22 Air rifle with a standard barrel. A good friend of mine has been using 40 Grain Bullets in his modified, but regular barrel, Career for years and they are as accurate as anything else out there. He fires them at close to the speed of sound, so that may have something to do with it.

 
At August 20, 2007 9:10 AM, Anonymous Anonymous said...

hi bb
i have a storie about the confusion about pelltes and bbs. i was buying my 392 at a sporting goods store and the salesman came over. he informed me i could use any ammo on the shelf just not the plastic (airsoft) bbs. he then picked up some .177 pellets and steel bbs and said "these should work" i was shocked . its oone thing when you dont know what your talking about but to have the store employee know nothing is just wrong.
Nate in Mass

 
At August 20, 2007 9:12 AM, Anonymous fflincher said...

I've noticed there is one brand of pellet that is difficult to load into my airguns in both .177 and .22. It's made by Benjamin and marketed as "H C" for "high compression".

These give only marginal accuracy in some of my guns.

Can you please tell me more about this situation?

fflincher

 
At August 20, 2007 11:50 AM, Anonymous MajorKonig said...

BB ,

If your subject used a barrel with a higher twist rate in his Condor, that would stabilise the 40 gr bullets, what kind of behaviour would you expect 28 gr Eun Jins to display with the new barrel ? Do you think being spun that fast would make them scatter (over stabilization) or would they be ok with a twist faster than required ?

 
At August 20, 2007 1:38 PM, Anonymous Anonymous said...

BB - couple of updates:

The leapers (accushot) 1-piece scope mount fits and works well on my diana 48 springer (with shimming, of course!). The stop pin is adjustable and I have over 1,000 shots without the pin jumping the small stop hole. Take care when tightening the stop pin down. First I put the clamps on the rail and then tightened down the stop pin... but the first time was too much and I ended up effectively shimming the front of the scope! The next time, I felt the mount while tightening the pin and stopped at the point where you can feel the pin start to shift the mount position - then finished tightening the rail bolts.

Next - I tried the Weihrauch Magnum .22 pellets in my gun and they group well. I find they fit nicley in my barrel and not as tight as the beeman pellets. Actually, I find most of the beeman pellets fit quite tight in my barrel.

Ozark

 
At August 20, 2007 1:57 PM, Blogger B.B. Pelletier said...

MajorKonig,

To answer your question someone would have to actually test your theory or question. Do you remember those spiraling pellets? That's what MIGHT ha[ppen. Perhaps not to the Eun Jins, but to Kodiaks.

B.B.

 
At August 20, 2007 2:03 PM, Blogger B.B. Pelletier said...

fflincher,

What color tins are your Benjamin pellets in?

B.B.

 
At August 20, 2007 6:41 PM, Anonymous Scott said...

BB,

Just a quick question.
How exactly would one best lubricate a fixed barrel air rifle, a Gamo CFX to be exact?
Also, what type/brand of oil would be best, and how often should this be done, i.e. number of shots between lubing?
I am guessing that a few drops of Crosman RMOil down the muzzle allowed to run down into the piston for at least two hours, but I am unsure.
I don't see it as necessary yet, but it would be nice to know to ensure top performance and the longevity of my air rifle.

-Scott

 
At August 20, 2007 7:24 PM, Anonymous Anonymous said...

I'm looking to buy a middle priced springer ($200-$325) for hunting and the occasional field target event. Scope mounting is important and so is shootability. I'm stepping up from a gamo 220. A R7 or R9 would be ideal, but too pricey. What would a used r9 sell for?

thanks,hb

I'd sell my 220 and maybe a recon. I like my bengi, and walther cp, and izh 46m pistol to much to sell.

 
At August 20, 2007 7:34 PM, Anonymous Anonymous said...

i was thinking BAM 40 or maybe the rws 34 panther or wood stock. I prefer wood but i can settle. A hamerelli could work. As we know their pistols are top notch (but not the best!). Of these rifles, which is best for my needs?
thanks,
hb

 
At August 20, 2007 8:19 PM, Anonymous Anonymous said...

CFX or b26 included

 
At August 20, 2007 9:25 PM, Anonymous Anonymous said...

What about the beeman cheap guns (like copies of the Rx's)

 
At August 21, 2007 12:40 AM, Anonymous Anonymous said...

hi bb,

i was wondering if you could tell me where i could find spare screws for a gamo rifle. i have a shadow 1000. im looking for the screws that would hold the stock to the receiver. thanks in advance

 
At August 21, 2007 7:01 AM, Blogger B.B. Pelletier said...

Scott,

The method you describe for lubing a fixed-barrel rifle is correct.

This chamber oil is what you want:

http://www.pyramydair.com/s/a/accessory/1015

Crosman RM oil sounds like the right stuff, as well.

B.B.

 
At August 21, 2007 7:06 AM, Blogger B.B. Pelletier said...

hb,

It sounds like you still need to give this some thought. What I think shouldn't influence you. All the rifles you mention are worthy guns. A used R9, if you can find one by itself, should sell for around $250.

B.B.

 
At August 21, 2007 7:15 AM, Blogger B.B. Pelletier said...

Gamo,

Contact gamousa.com for Gamo parts.

B.B.

 
At August 21, 2007 7:25 PM, Anonymous Anonymous said...

So then shooting eun jin .22's out my hunter1250 in .22cal will be alright?

 
At August 22, 2007 7:50 AM, Blogger B.B. Pelletier said...

hunter 1250,

It won't hurt the rifle, but they may not be very accurate, either. I have shot them in a Beeman R1 and they were terrible.

B.B.

 
At August 22, 2007 10:23 PM, Anonymous fflincher said...

BB, the Benjamin High Compression pellets I have been using are in a green tin with black lettering.

fflincher

 
At August 23, 2007 5:50 AM, Blogger B.B. Pelletier said...

fflincher,

I Thought so! Your pellets are 30-50 years old at the least. They have swollen due to led oxydation and they were made fatter to begin with.

Stop shooting them (they are collectible - save what remains) and use modern pellets.

B.B.

 
At February 03, 2009 7:32 PM, Blogger Andrew M. B. Boktor said...

This post has been removed by the author.

 
At February 03, 2009 7:33 PM, Blogger Andrew M. B. Boktor said...

Does a smoothbore rifle has no spin rate?
I read that air rifles made to shoot BBs and pellets have smooth bores, does this mean that they won't provide any spin for the pellets which of course will decrease accuracy?

 
At February 03, 2009 8:22 PM, Anonymous .22 multi-shot said...

Andrew,

It depends. Some barrels that shoot either pellets or BBs use polygonal rifling. BB wrote an article about types of rifling. See the following

http://www.pyramydair.com/blog/2006/08/different-types-of-rifling.html

.22 multi-shot

 

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