# I think I discovered why supersonic pellets are not accurate



## rogervan

And it's not just the ammo design, even though the ammo can't fly at over soundspeed. In hypersonic rifles the pellet tumbles as long as it's above soundspeed. I don't know how they fly once they are traveling at reasonable ft/sec (probably ten feet from the barrel.), but I doubt it's a good start for an accurate shot.

The second nail is this: With break-barrels, the barrel does not return to the same position every time. A factory rep told me that, and he was talking in general and not putting down some other maker. And it's short. Even fractions of a thousanth inch difference magnify at 100 feet. I'm sure the best manufacturers put a lot of work and skill into limiting that variable.

Add these two sources of error and you have a rifle that just can't shoot well at above 200 feet, or even less. For accuracy, go to PCP.

OMG I saw an advertisement for a break rifle that shoots at 1500 ft/sec. I'm impressed, but what's the use?

Roger


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## rogervan

I don't know the difference, and I didn't look it up to find out which term to use in my post. When I use either term, I mean faster than the speed of sound in air at STP.

BTW, I hope you guys prove me wrong in some part of this idea. I want the variables in my expensive rifle to be not there, or at least, controllable.

Roger


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## Ambush Hunter

Pellets do become unstable at supersonic speeds and more than often way before that. Lots of folks bring their centerfire mentality into airgunning thinking more is better when in fact, Less is More.

Break barrels are accurate. A great example are German Weihrauch rifles. Some of them are used in spring-class airgun competitions.

Not sure what do you mean 200 feet or less...as far as effective range for hunting, well, I've killed LOTS and LOTS of squirrels, pigeons, crows, rabbits, and p-dogs over the years with spring-piston airguns including break barrels out to 75 yards. Yes, PCP will get you farther but you need to make sure you have enough air for your hunt. PCPs have their advantages but so do springers...


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## rogervan

The German Weihrauch rifles are not break-barrel, they cock from the side, making it possible to have a solid barrel from breech to tip. But yes, I've never seen these before, and they do seem to be an ideal design for a spring-action rifle.

My statement about break-barrels is still valid, IMO

Roger


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## Ambush Hunter

Sir, the only person you are getting confused is yourself. Obviously you have no idea what Weihrauch is. I own FIVE of them and FOUR are break-barrels.

http://www.weihrauch-sport.de/englisch/ ... _index.htm


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## rogervan

Well, to get the original information I Googled the company and got Cobra (I thought I had gotten Weihrauch), who I see now is just a retail seller. They displayed two Weihrauch rifles, the HW100S, and the HW100T. I thought those were the rifles Weihrauch sells. So I guess I am missing some information, but I'm not missing all information. My statements are true about these two rifles.

All I'm doing here is trying to find out why some rifles shoot out to long distances, and other (not cheap) rifles shoot out to thirty yards. There is no need to get bummed. Why not just tell me I'm missing information, without putting all that tone in your reply. I enjoy civil discussions.

Roger


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## spentwings

rogervan said:


> The second nail is this: With break-barrels, the barrel does not return to the same position every time. A factory rep told me that, and he was talking in general and not putting down some other maker. And it's short. Even fractions of a thousanth inch difference magnify at 100 feet. I'm sure the best manufacturers put a lot of work and skill into limiting that variable.
> 
> Roger


Yes, but it's probably an insignificant variable in a good quality break barrel for the average/above average shooter.


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## farmerj

since it will change the line of sight with your eye and the cheek weld...

In a 20" long sight radius, a change of 0.008" will change your point of impact 1" at 100 yds.


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## Ambush Hunter

rogervan said:


> Well, to get the original information I Googled the company and got Cobra (I thought I had gotten Weihrauch), who I see now is just a retail seller. They displayed two Weihrauch rifles, the HW100S, and the HW100T. I thought those were the rifles Weihrauch sells. So I guess I am missing some information, but I'm not missing all information. My statements are true about these two rifles.


First of all, 100S and 100T is the same gun. It's a PCP. Only stock is different. Secondly, you say "your statements are true about these two rifles" but I don't see any statements being made about these two rifles other than Cobra having them for sale. What are your statements? You said your statement about break-barrels are still valid...you was so positive that Weihrauch don't make any break-barrels, only side-levers...well, it turned out that was not true at all. First, you positively state incorrect information but then getting upset when someone corrects you. Remember that humans have a hyper-ability to misinterpret PRINTED words since there is no way to express any emotions, body language, and demeanor...well, unless you are a professional writer...I am not.
I was short, respectful, and straight to the point. I even used the "sir" word... I too enjoy respectful discussions. :beer:

Now, as far as side-lever rifles, RWS makes them, not Weihrauch.


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## rogervan

farmerj said:


> since it will change the line of sight with your eye and the cheek weld...
> 
> In a 20" long sight radius, a change of 0.008" will change your point of impact 1" at 100 yds.


Way cool. I'll do the math too. I should have thought of that as I was initiating this discussion.

I'm just a complete beginner trying to zero in on the truth. What got me started was someone wrote that break-barrels are accurate out to thirty feet. That got me going. I enjoy chasing down the facts, and many of you are being very helpful. My mistake about the nature of the Weihrauch rifles was unfortunate, but what the hell, the road to the final answer is seldom straight, and I make mistakes. I wish I had five of hose rifles. Over fifteen years, I've worked my way up to expert in one narrow herpetology forum, but I started there as a rank beginner. I can do the same here.

What I'm going to do now is build an ultra-stable rifle clamp, and see what happens when I make several shots from the exact same position, with different weights of ammo. I'll be shooting about 100 feet, and seeing all the responses here leaves me hopeful that I can leave this topic behind.

Roger


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## rogervan

farmerj said:


> since it will change the line of sight with your eye and the cheek weld...
> 
> In a 20" long sight radius, a change of 0.008" will change your point of impact 1" at 100 yds.


I measured the length of the barrel on my rifle, and it's 13 inches. The sighting is on the body of the rifle, and deflections of the barrel won't affect the way the scope sees the target. Check me on this: I'm thinking we have to find the deflection radius along a thirteen inch line, because the barrel is the only thing that can "bend", or change it's angle. Now I have to figure out what the radius of a cone is at 100 yards, from a line propagated on it's side that starts out as 13" long with a 0.008" flop. Right now, I don't know if that will even make a difference.

Whatever happens in this conversation, I'm going to test some of the heavy pellets that someone mentioned. I did not know anyone actually made them. They might reduce the muzzle velocity. Can extra-heavy pellets damage my break-barrel rifle?

I'm starting a savings account for an extra-good PCP.

Roger


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## spentwings

:homer: And here I thought the beauty of a springer was it's simplicity.
_Vc = sqrt(M * G / r) 
Vesc = sqrt(2 * M * G / r) = sqrt(2) * Vc 
V^2 = u/a 
P = 2 pi/(Sqrt(u/a^3)) 
K = 1/2 V**2 - G * M / r (conservation of energy) [= hold, follow through, and practice]_


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## farmerj

I shoot high power rifles out to 1000 yards. Yes, three zeros there.

It's the same principle regardless of what you shoot.


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## spentwings

farmerj said:


> I shoot high power rifles out to 1000 yards. Yes, three zeros there.
> 
> It's the same principle regardless of what you shoot.


That may be true but comparing high power rifles to springer airguns is like asking "compared to an apple... how far can I throw apple sauce?".


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## farmerj

Sight radius and sighting in your device is the same regardless.

movement of your head, eye or the barrel WILL change your POI. regardless of WHAT you shoot.


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## spentwings

farmerj said:


> Sight radius and sighting in your device is the same regardless.
> 
> movement of your head, eye _*or the barrel *_WILL change your POI. regardless of WHAT you shoot.


Like I said...that may be true but considering what a springer is usually used for and the ranges involved...it's relevancy is :-? ????
Practice, hold, and follow through will make you a good springer shot...not worries about the break barrel.


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## farmerj

and bad form is bad form. regardless of what you shoot.


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## spentwings

No disagreement there...only the impact/relevancy of a break barrel on accuracy.


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## farmerj

my point is...

Your cheek goes against the stock.

The sights are attached to the barrel.

If the barrel breaks and does not return to the exact same point, your line of sight WILL change.

Due to it being a mechanical device, it will NOT return to the same point. How far it is off, that's a crap shoot.

Even at 50 yrds, it's 1/2".

May not be a big consideration in air or spring rifles like you think, but it is more than you think.


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## blowgunner62

rogervan said:


> I'm just a complete beginner trying to zero in on the truth. What got me started was someone wrote that break-barrels are accurate out to thirty feet.


Break barrel air rifles can be accurate WAY past thirty feet. Thirty feet is only ten yards. My break barrel will shoot accurately past 20 yards. Some will shoot accurately at 100 (the Feinwerkbaus and some others.)


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## rogervan

rogervan said:


> farmerj said:
> 
> 
> 
> since it will change the line of sight with your eye and the cheek weld...
> 
> In a 20" long sight radius, a change of 0.008" will change your point of impact 1" at 100 yds.
> 
> 
> 
> I measured the length of the barrel on my rifle, and it's 13 inches. The sighting is on the body of the rifle, and deflections of the barrel won't affect the way the scope sees the target. Check me on this: I'm thinking we have to find the deflection radius along a thirteen inch line, because the barrel is the only thing that can "bend", or change it's angle. Now I have to figure out what the radius of a cone is at 100 yards, from a line propagated on it's side that starts out as 13" long with a 0.008" flop. Right now, I don't know if that will even make a difference.
> 
> Whatever happens in this conversation, I'm going to test some of the heavy pellets that someone mentioned. I did not know anyone actually made them. They might reduce the muzzle velocity. Can extra-heavy pellets damage my break-barrel rifle?
> 
> I'm starting a savings account for an extra-good PCP.
> 
> Roger
Click to expand...

My geometry reasoning is not valid. 100 yards, and the presumed amount of deflection of 0.008, is not changed by the length of the barrel. Instead, the presumption is a 0.008 deflection, period. Easy math. I'm dropping this subject before you guys H-Bomb my house.

Roger


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## blowgunner62

Don't use extra heavy pellets in your springer. It will damage it.


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## rogervan

farmerj said:


> I shoot high power rifles out to 1000 yards. Yes, three zeros there.
> 
> It's the same principle regardless of what you shoot.


If you can perform out at 1,000 feet, you are both trained and talented. I'd like to be that good, but not everybody can do it. My hat is doffed to you.

Roger


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## farmerj

rogervan said:


> farmerj said:
> 
> 
> 
> I shoot high power rifles out to 1000 yards. Yes, three zeros there.
> 
> It's the same principle regardless of what you shoot.
> 
> 
> 
> If you can perform out at 1,000 feet, you are both trained and talented. I'd like to be that good, but not everybody can do it. My hat is doffed to you.
> 
> Roger
Click to expand...

Actually, you can. If you can shoot consistent groups out to 100 yards, 1000 yards is only intimidating until you do it. Then it becomes addicting.

The principals to shoot small groups at 100 yards is no different than if you shoot 1000 yards.

The same mathematical principals apply as well. It's just magnified depending on the distance. 1" at 100 yards is 10" at 1000 yards.

So it's just a matter of changing a persons fear of "damn, that's a long ways"....


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## rogervan

farmerj said:


> rogervan said:
> 
> 
> 
> 
> 
> farmerj said:
> 
> 
> 
> I shoot high power rifles out to 1000 yards. Yes, three zeros there.
> 
> It's the same principle regardless of what you shoot.
> 
> 
> 
> If you can perform out at 1,000 feet, you are both trained and talented. I'd like to be that good, but not everybody can do it. My hat is doffed to you.
> 
> Roger
> 
> Click to expand...
> 
> Actually, you can. If you can shoot consistent groups out to 100 yards, 1000 yards is only intimidating until you do it. Then it becomes addicting.
> 
> The principals to shoot small groups at 100 yards is no different than if you shoot 1000 yards.
> 
> The same mathematical principals apply as well. It's just magnified depending on the distance. 1" at 100 yards is 10" at 1000 yards.
> 
> So it's just a matter of changing a persons fear of "damn, that's a long ways"....
Click to expand...

At 1,00 yards, you have to hold up quite a bit (maybe 3" in certain cases, ten inches in others.). And downfield wind will deflect your shot.

Nevertheless, talking about purely me, I would gladly purchase the rifle and ammo to do 1/2 mile target shooting. I'd put clangers way out there. It would be a blast.

Roger


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## Ambush Hunter

Farmerj, I understand where you are coming from...but may I just say that third of all Marine sniper school students fail long range tests completely.
It's a huge number if you think about it. 1000 yard shot is a long shot even for a well-experienced shooter. There is a reason that sniper teams consist of TWO persons - shooter/spotter.

Meteorological, environmental, and physical conditions are rarely stay the same. At 100 yards you don't really have to worry too much about ballistic coefficient, wind speed, angle, tempreture, humidity, elevation, and so forth. But at 1000, boy, now we are talking! Just squizzing that trigger at the point of a second stage break AT the "wrong" phase of your heart's rhythm can throw you off your target completely at 1000 yards. Something to think about...


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## fprefect

rogervan said:


> And it's not just the ammo design, even though the ammo can't fly at over soundspeed. In hypersonic rifles the pellet tumbles as long as it's above soundspeed. I don't know how they fly once they are traveling at reasonable ft/sec (probably ten feet from the barrel.), but I doubt it's a good start for an accurate shot.
> 
> The second nail is this: With break-barrels, the barrel does not return to the same position every time. A factory rep told me that, and he was talking in general and not putting down some other maker. And it's short. Even fractions of a thousanth inch difference magnify at 100 feet. I'm sure the best manufacturers put a lot of work and skill into limiting that variable.
> 
> Add these two sources of error and you have a rifle that just can't shoot well at above 200 feet, or even less. For accuracy, go to PCP.
> 
> OMG I saw an advertisement for a break rifle that shoots at 1500 ft/sec. I'm impressed, but what's the use?
> 
> Roger


Nonsense. What keeps any projectile from tumbling is rotation imparted by the barrel's rifling. The speed of sound is completely has no bearing on this issue whatsoever. The manner of propulsion, be it compressed air or compressed gases from a centerfire bench rest rifle that I have shot thousands of rounds through makes no difference whatsoever.

I've shot air rifles since I was a kid, but don't consider myself an expert on their method of sending a projectile to a target, but the principles are exactly the same. The "tighter" (the more turns over a given distance of barrel length) the rifling the more RPMs the projectile will be turning as it leaves a barrel if both projectiles are shot at the same velocity. The heavier the bullet the more "twist rate" will be necessary in order to keep the bullet from tumbling as is loses velocity and also spin rate.

I have no idea what the typical rate is for an air rifle, but to give you an example of the what happens when the the spin rate is insufficient is the early reports of the M-16 rifle producing "devastating" wounds due to the bullet tumbling after striking the target. In fact, the bullet had already begun to tumble BEFORE reaching the target and by sheer luck the target was hit before the projectile rapidly lost it's velocity and fell harmlessly to the ground.

The culprit. A 1 in 14" rifling twist and a 55 grain bullet which was too heavy to be stabilized in many cases for more than 2 or 3 hundred yards before beginning to tumble. The velocity of the bullet in question? Well in excess of 3000fps when leaving the muzzle which the last time I checked was well in excess of the speed of sound and were perfectly stable for the first 300 yards or so. The fix. A 1 in 10" or 1 in 12" twist when using a 20 inch or shorter barrel.

It's no different with a pellet, although the shape of the pellet will cause a flat nose type to lose velocity and the spin rate more quickly than one with a pointed tip.

Granted, the slower flat nose "match" pellet tends to be more accurate but not because of anything to do with velocity or spin. At the ranges velocities they are fired plenty of spin remains to keep the pellet stable at ranges of 10 to 15 yards which is all that is required. But the real reason these slower traveling flat nose pellets take home all the hardware has more to do with the mechanism of "firing" the pellet. The RIFLE or I should say the method the rifle uses to produce the necessary compressed air to shoot the pellet down range.

As you correctly point out, the spring/piston barrel break rifle can never be returned to it's original position after each shot, where as the pump up rifle can be, making it inherently more accurate, at ANY velocity including above the speed of sound if the shooter needed that much velocity. But with most matches being held indoors where wind is not a factor, a lower pressure rifle creates less vibrations when fired than one that could be charged to propel a pellet faster than the speed of sound so most of the megabucks competition rifles stay in the 600 to 800fps range which is sufficient velocity to impart enough spin to keep the pellet stable over the needed distance.

As I stated above I am no expert when it comes to pellet rifle accuracy other than to know, like any rifle, including the 15+ pound centerfire bench rifles that I shot in competition for years, the key to accuracy is consistency from one shot to the next, and not Whether or not the projectile is traveling above or below the so called sound "barrier".

F. Prefect


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