Where could one find a gem like thisverbatim,with typo's as in original): "Well...just got off the phone with Sierra ballistic lab. Told him of our little debate about bullet rpms. He got a good laugh,but bottom line is he said all of you that think that what ever the rifling twist is,is all that bullet turns in that distance....example 30-06 with 1 in 10 twist so the bullet only turns 1 time in 10 inches of whatever it's going through...ARE ALL WRONG ,that I was right.the bullet is spinning those very high rpms,in other words if you have a 30-06 shooting a 150 gr bullet at 2700 fps out of a 1 in 10 twists the bullet is spinning 2700 x 720 divided by 10 to equal 194,400 rpms as soon as it comes out of the muzzle !!!!! Well, I'm finished,you nay sayers take it up with Sierra,Hornady,Speer and any other ballistics engineer you wish to discuss with. Faster the twist,the more energy impartedin the bullet,the more destruction on the target." Joe AND IN THE POST IMMEDIATELY FOLLOWING IS THIS----"Joe is correct.Work thru the units and it will give you his answer"----------------------...............

Idabull, 194,400 rpm equals 1 rotation every 10" in theory. "In theory" meaning that the bullet would not slow down in time or distance which in practical application is not possible with natural laws of physics.

Dennis

While the velocity slows very quickly the RPM or rate of spin slows very little over the distance of a bullets flight.

Larry Gibson

quote:

Originally posted by idabull:
Where could one find a gem like thisverbatim,with typo's as in original): "Well...just got off the phone with Sierra ballistic lab. Told him of our little debate about bullet rpms. He got a good laugh,but bottom line is he said all of you that think that what ever the rifling twist is,is all that bullet turns in that distance....example 30-06 with 1 in 10 twist so the bullet only turns 1 time in 10 inches of whatever it's going through...ARE ALL WRONG ,that I was right.the bullet is spinning those very high rpms,in other words if you have a 30-06 shooting a 150 gr bullet at 2700 fps out of a 1 in 10 twists the bullet is spinning 2700 x 720 divided by 10 to equal 194,400 rpms as soon as it comes out of the muzzle !!!!! Well, I'm finished,you nay sayers take it up with Sierra,Hornady,Speer and any other ballistics engineer you wish to discuss with. Faster the twist,the more energy impartedin the bullet,the more destruction on the target." Joe AND IN THE POST IMMEDIATELY FOLLOWING IS THIS----"Joe is correct.Work thru the units and it will give you his answer"----------------------...............

Idabull; you poor, poor man, I feel sorry for you. I'll say a prayer for you and hope you are better soon, God bless. Scot

quote:

Originally posted by Larry Gibson:
Dennis

While the velocity slows very quickly the RPM or rate of spin slows very little over the distance of a bullets flight.

Larry Gibson

I agree with Larry, and therefore agree with this original(OLD) post by starmetal. At extremely long range it is sometimes referred to as "over mstabilization" causing nose up trajectory. So Idabull, yes I guess you are correct, it is a gem, but somehow I don't think you meant it as a compliment. Trolling is for fishing, not here though, you need to go to a lake and jump in.

Beer has medicinal properties! Drink one and you will feel better!

It is quite possible for a bullet to be brought to a halt in a very short distance within an animal, in which case, the energy of spin has got to go somewhere - heat maybe? Has anyone actually noticed a difference in wound effects between a fast spinning bullet and a slow spinning bullet? What is the percentage spin evergy against the forward energy of a bullet? How exactly is spin energy translated into tissue damage? What is the actual spin energy of a bullet?

I ask about noticing a difference because I have not. I have seen a difference due to bullet shape and/or contruction and no difference between a fast light bullet with its high spin rate and a slower, heavier and bigger bullet with slower spin rate. An even slower spin rate bullet with even lower velocity but with a slight flat pointed shape does the same damage as a much faster bullet with a higher spin rate. An anecdotal observation - a 22 Hornet firing a 55gr SP bullet compared to a 308 Win firing a 165gr? bullet at similar velocity did the same damage to a turkey at 200m. Twist of the hornet? 1-in-16. Twist of the 308? 1-in-10. (Could have been 1-in-12). Either way, the hornet bullet was much smaller and had far less energy both forward and spin but did the same damage! A 223 with the same weight bullet and 1-in-12 twist at higher velocity did a little more damage at that range. Go figure!

quote:

I ask about noticing a difference because I have not. I have seen a difference due to bullet shape and/or contruction and no difference between a fast light bullet with its high spin rate and a slower, heavier and bigger bullet with slower spin rate. An even slower spin rate bullet with even lower velocity but with a slight flat pointed shape does the same damage as a much faster bullet with a higher spin rate. An anecdotal observation - a 22 Hornet firing a 55gr SP bullet compared to a 308 Win firing a 165gr? bullet at similar velocity did the same damage to a turkey at 200m. Twist of the hornet? 1-in-16. Twist of the 308? 1-in-10. (Could have been 1-in-12). Either way, the hornet bullet was much smaller and had far less energy both forward and spin but did the same damage! A 223 with the same weight bullet and 1-in-12 twist at higher velocity did a little more damage at that range. Go figure! bewildered

Bullet construction in relation to velocity! My .220 Swift bullets would explode on a blade of grass or blow a chuck to mush. But take a solid bullet and it would poke a pencil hole. Shoot a small animal with a 110 gr 30-06 bullet and you get a red mist but a 180 gr makes a small hole.
I don't think spin has much effect at all in an animal unless it makes the bullet tumble.
Use rpm's for flight stability and bullet construction for it's effect on game. There is no way to compare only the spin rate on game because the wrong bullet will come apart if spun too fast as soon as it touches the hide when the correct bullet will work very well at the same spin rate and a tough bullet will just poke a small hole.
To make tests valid, you need one caliber, the same velocity and the same twist with different constructed bullets.
Yes, the velocity controls the spin of a bullet from a given twist.
That is why I like a little faster twist. I can reduce the load to slow the spin for the best accuracy and stability. A twist too slow is hard to work with because pressure and velocity restrictions might keep one from reaching the correct spin for a given bullet.
BR shooters like a slow twist for 100 and 200 yd's because it eliminates yaw around the flight path. An over spun bullet will shoot tighter at long range then it will at close range because it will go to sleep at distance because the spin rate DOES slow. Not as fast as velocity but it does slow to what the bullet prefers.
In a nutshell, close range shots need a slower twist and long range needs faster.
I do not believe there is any connection between spin and velocity once the bullet leaves the bore. Once velocity drops, if the spin is still good, the bullet is still stable. Or if the spin is right for the bullet, high velocity still works at close range.
Notice how revolver shooters ignore twist rates! Rifle shooters are VERY picky.

Very interesting, thank you! I have wondered whether spin could be having an influence on the rate of bullet expansion on impact due to it being radially stressed by centrifugal forces. This may have lead to the perception that spin energy adds to tissue damage. But if this were so then it would likely only apply when the bullet construction and spin rate are at some critical balance, maybe?

303guy:In the thread @ Cast Boolits that the title post here was extracted from you can find(@ post # 155) a method for determining rotational energy.in the example supplied there the calculation was done using a 150 gr 330 cal.bullet at or about 2000 fps ,giving 1350 fpe.& the calculated rotational energy was 4.33 fpe(about 0.3% of the liner energy).That thread was during the time Starmetal(aka Joe,MaxPayne,old joe, et al ,ad.naus.)was doing his"sentence at castboolits sic,sic,sic" and might still be reviewed in whole. There has been some tinkering with post count records and content done on that board,so if you look and don't find get ahold of me privately. Or wait for the book !! Idabull

swheeler: From some of th4 content I've read in your posts,I don't think it would be wise for me to put much hope on your prayers. I'd evaluate your standing with God as about the same as the Jimmys(Jones & Swaggart).. Before you carry any more water on this post,you might remember that Starmetal(aka Joe, MaxPayne,old joe, et al ,ad.naus.)recanted the stuff shown in my first post above."Well fellows...GULP!....this is a hard post to do. Read very carefully. I WAS WRONG..did you get that? I'll repeat I WAS WRONG.I should have done the math instead of running my mouth..........." that came three days,and more than 120 posts to and fro, liberally laced with invective in the expected style,after the post first quoted above..Took more than another 3 YEARS though, for any public acknowledgement of the fact that there NEVER WAS a laughing guy at Sierra ballistic lab.. Idabull

quote:

(about 0.3% of the liner energy)

Mmmm.... that'll really make a difference! It must the 'spin enhanced expansion' theory at play then. Or not! I don't know. I do know my hornet with it's 'heavy for hornet' bullets did almost the same damage as a 223 and indistinguishable from a 308. Until enter my 303 Brit with starting loads af around 2200-2300fps doing as much damage as a 22-250! How can such a slow bullet do so much damage on such a small target? Spin rate? Bullet shape? The same bullets did not blow up on feral goat!

quote:

Originally posted by idabull:
swheeler: From some of th4 content I've read in your posts,I don't think it would be wise for me to put much hope on your prayers. I'd evaluate your standing with God as about the same as the Jimmys(Jones & Swaggart).. Before you carry any more water on this post,you might remember that Starmetal(aka Joe, MaxPayne,old joe, et al ,ad.naus.)recanted the stuff shown in my first post above."Well fellows...GULP!....this is a hard post to do. Read very carefully. I WAS WRONG..did you get that? I'll repeat I WAS WRONG.I should have done the math instead of running my mouth..........." that came three days,and more than 120 posts to and fro, liberally laced with invective in the expected style,after the post first quoted above..Took more than another 3 YEARS though, for any public acknowledgement of the fact that there NEVER WAS a laughing guy at Sierra ballistic lab.. Idabull

My point being-LET IT GO! ancient history man- cheeeeeeeeeeeze! As far as carrying water I have no idea what you are talking about? Joe and I don't always agree, that's just part of life, but we don't hold a grudge for YEARS either. You couldn't even carry my lunch box! Move on, grow up, let it go! I will still say a pray for you, there is always hope, even for the most dispicable soul. God bless- Scot

swheeler: I must have missed the memo appointing you a decision maker on this forum!! Seems as though you get to cry"lie,lie,lie" when you see what you believe is a mistaken opinion,but the serial stone liar starmetal(aka joe,MaxPayne,old joe, et al,ad.naus.)gets a pass..No need for prayer,as from what I heard,things are not really serious with that guy unless a death threat is sent out..

Idabully; go to your anger management classes, take your meds as perscribed and you will feel better! Try to get past the eighth grade games, grow up and grow a pair. You have a nice day now, you hear. Scot

swheeler: you choose to post on a thread that has nothing to do with you..then ,when your opinion turns out to be an embarrassment.it's time to hit the trash talk button again..and I'm the one that need anger management classes !!! long tough winter there,eh ???

quote:

when your opinion turns out to be an embarrassment.

1- not opinion, but fact and a very hard one to get across to a novice
2- do you even own a gun, or have you ever actually shot one? do you or have you ever reloaded?
3- there is misinformation on this thread, but it is not from me, some of you kids need to READ and DO before you post!
4- Are you carrying water for your boyfriend? Been sick? depression? There's definately something wrong with you to keep dragging something up from years ago off another forum, what is your problem(hell I don't even remember the thread and don't think I even posted in it). You definately have some kind of mental issue! You are one of those "know it alls" that doesn't know shit, a keyboard shooter, reloader and hunter. I can actually see that even Larry has distanced himself from you, I would commend him for that intelligent move Joe is correct, you don't warrant a response, just ignore your ignorant ass.

swheeler: Ok, lets say I have one firearm less than you,& I load for 14 centerfires and 4 shotgun gauges,all with the Lee kits I got last Christmas. As to casting I'm using a single cav.Lyman wadcutter mould I got at a y'dsale last fall.and hope to move to a 2c with all the help I've found on forums like this.!! Now then what had changed.?? Starmetal(aka joe,MaxPayne,old joe, et al ad naus.)still knows what he is, as do I, and,expect you do ,too.I am reminded of the time when Starmetal and his buddies of the time were trashing on "Aladin"including accusing Jay D. of skipping out with some group buy $ ..If Jay had any commercial interests to show damage to, Starmetal would still be on a street corner,with a tin cup & signboard " need help,---broke--and in pain" (or the internet equivalent thereof) Think about it, if I'm on your "ignore" this post will work its way off the front page. Than I might be need to post another Joe and the laughing guy at/from xxxx.. story.. You could catch up when the book comes out....

Just to muddy the waters at VERY long ranges there is significant reduction in rpm. Understand that at long ranges the bore axis is superelevated THEORETICALLY (ignoring aerodynamic effects) the bullet would remain in that orientation
(parallel to the bore axis) until impact

where things get messed up is in the interaction between
Aerodynamic forces and gyrscopic forces as the bullet reaches apogee on it's trajectory to the target

the gyroscopic forces cause precession (varying from wobble to a perfect broadside keyhole) when ANY force disturbs the bullet from it's "launch axis"

An "understabilized" bullet with a flat base will actually "weathercock" to some degree
(artillery shells do!) but it will "wobble" for some period of time before and after it goes "over the top"

that wobble not only presents a less efficient aerodynamic
shape in the direction of flight, but due to the conservation of energy it "slows" the rotation rate.

this "understabilization" Overstabilization can cause some counter-intuitive effects... because the faster spinning bullet will often actually wobble more and continue to wobble for a greater period of time before it "settles down" again.

the fact that in some flight regiems the aerodynamic forces will actually cause the bullet to "Weathercock" and return to stable nose on flight AFTER it has shed rotational energy.

This phenomena is used in antiaircraft projectiles in a device known as a "spin decay fuze" that prevents those high explosive shells from returning to earth, by detonating the shell in flight (at altitude) where it is more or less harmless
Rather than letting it come back down and hit... a Hospital, a School, Church.... a Marine Barracks?

AD

Here are a couple paragraphs taken from Principles and Practice of Loading Ammunition, by Earl Naramore.........

PAGE 432

"If the same bullet were fired at very high velocity from a barrel with a rapid twist of rifling, an overspin would be imparted to it that would prevent it's point from following the trajectory. The center of gravity would follow the trajectory but the bullet would tend to maintain it's long axis parallel to the angle of departure. This would cause the bullet to be slowed down rapidly by presenting more and more of it's side to the resistance of the air and this, in turn would tend to make the bullet unstable in flight."



Page 433

"It is clear that if the forward velocity falls off more rapidly than the rotational velocity, that the bullet that started out turning once in ten inches will soon be traveling less than ten inches while making one revolution and that this difference will increase with the range so it amounts to an overspin at the longer ranges."



So I guess from what I read Joe was correct in his original statement made 3 or 4 years ago. As usual my .02 Scot

swheeler: If you truly believe Starmetal(aka Joe,MaxPayne, old joe,et al, ad naus.) would come to groveling on a public board if he was right,it's probably hopeless to try..BUT, consider this: Chuck a bullet of your choice in a lathe,power up to the max..RPM is whatever the lathe will deliver, twist rate of the bullet is 0 in 0..Or consider the bullet that leaves the muzzle of a 1 in 10 twist barrel and flies for 100 inches downrange,it turns over 10 times whether the muzzle velocity was 1,2,or 3 thousand fps.RPM is increased with increasing velocity but the number of turns the bullet makes at equal distances is the same...The quoted material from pg.433 of Cap't.Naramore's book shows us a least 2 things. First,all the published BS out there didn't originate on the internet, Second,some insight as to why he didn't make it off the Captains list..

quote:

Ignored post by idabull posted 14 March 2009 02:29

Life is good!!!!!! I now have three on my ignore list-BBBruce-DaMan-Idabull. I think the names on my list speak for themselves

swheeler: one more cheapshot attempt at the last word,eh. not going to happen..