The Accurate Reloading Forums
twist AFTER total expansion
16 December 2006, 19:00
jeffeossotwist AFTER total expansion
yes, these are .308s, and barnes...
http://www.barnesbullets.com/x-citingfacts.php
clearly shows twist after max temporary channel
apparently it doesn't take "much" to open up a .308 TSX... this is a FACTORY load 308 win
2 INCHES
lastly,
hmmm, this one will cause a stir... as the bullet slows, the rotation doesn't slow proportionally...
that is, the bullet keeps twisting as the velocity slows... as evidenced by, initially, the waves (frequency) being farther apart, but as the bullet slows, they grow closer together... clearly showing the velocity slowed MORE than the rotation.
16 December 2006, 19:33
Idaho SharpshooterIs that sweet, or what?
Rich
NRA Life Member
DRSS
16 December 2006, 19:45
GabrielGuitarsActually, that doesn't surprise me. One has to remember that it technically is not the bullet itself that does the damage in that wound channel, but the shockwave that is pushed ahead of the bullet. This should make sense once you look again at the max diameter of that mushroomed bullet, and then look again at the diameter of the wound channel. In essense, the bullet is close to spinning in the air still, as the shockwave ahead of it is clearing the path for the bullet. As the shockwave is asked to do work (damage tissue, gelatin, etc.), the energy is reduced dramatically, hence the large initial wound, and the shockwave quickly dissipates, leaving the bullet to fend for itself.
16 December 2006, 21:44
ALF/
17 December 2006, 00:34
RIPAlf,
You confused the messenger. Address your comments to Jeffeosso, please, whom I thank for bringing the message.
This seems to show that maybe twist is important within the temporary cavity. Hell that may be a near vacuum.
Yes old tests found bullets shot into the air straight up on calm days would sometimes return to earth base first and spinning nearly as fast as when they left the barrel.
17 December 2006, 00:43
RIPquote:
Originally posted by jeffeosso:
From Barnes:
"The more rotations the bullet makes, the greater the odds of lacerating one or more vital organs."
Sounds like an endorsement for fast twist.
17 December 2006, 02:38
ireload2The photos need to be shot with the bullet still in the gelatin. I think you would see the waves spread laterally from the bullet and are not pushed ahead significantly.
17 December 2006, 03:08
jeffeossoireload..
shot barnes an email and ask if they have those pics
jeffe
17 December 2006, 04:45
boom stickthose bernes will come iN handy in the thick stuff when its easy to get chargerd
by a dangerous cube of gelatin
id hate to be trampled and clawed by one of those...
but seriously el jeffe that is some interesting stuff and damn good photography.
17 December 2006, 04:55
fla3006quote:
boom stick: those barnes will come in handy in the thick stuff when it's easy to get charged by a dangerous cube of gelatin
they're good on charging water jugs and steel plates too!
NRA Life Member, Band of Bubbas Charter Member, PGCA, DRSS.
Shoot & hunt with vintage classics.
17 December 2006, 05:06
POPSo based on this the TSX's should never have any "expansion" issues.
17 December 2006, 05:12
boom stickfrom what i gather they can be deformed by recoil in the mag and some dont open up but i think the big bores have stronger tips. so check to see if the tips are getting deformed in your rifle.
17 December 2006, 05:37
470 MbogoGood find on the pictures Jeff. Cool to see the actual rotations per inch of travel in a test medium.
Best of the season to you,
Dave
17 December 2006, 07:44
tiggertatequote:
Originally posted by ALF:
Again the Shock waves propagated in front of the projectile does no damage. It has been proven simply on grounds of the fact that the wave does not move tissue. It is propageted through the dense medium without moving the medium. ( we have to be careful about what we call shock waves and what are waves of pressure change that cause movement indense media. The temorary cavity gives a pressure wave but the fundamental quality of this is that it physically causes deformation, the acoustic wave in front of the bullet does not do this. What it does do is to effect change in cell membrane permeability in nerve cells and thus potentially effect changes in conduction.
Not to pick nits but shockwaves are capable of producing enormous damage in lung tissue. The passage through air pockets in the lungs causes ruptures of the soft tissues that don't occur in solid tissue. Just like the shockwave from a detonation in water shreds a diver's lungs and sinus cavities, so does a hyper-velocity bullet strike to a proportional degree.
"Experience" is the only class you take where the exam comes before the lesson.
17 December 2006, 11:09
GrandpasezShot a gelatin block with 350 gr
soft jacketed bullet at 3400 plus,
and the block disintegrated.It was
with my 458HE, few years ago.
1 to 22 twist.Ed
MZEE WA SIKU
17 December 2006, 11:29
shootawaygood for barnes,they have a good bullet
17 December 2006, 18:30
308SakoFirst of all appologies for mentioning a dinky caliber, and twist...
Great pictures, thanks Jeffe
A while back I was contemplating a fast for caliber re-barrel and the vast mind of the forum concluded that using a 1 in 8 say for a .30 cal was a waste of time. I did specifically mention that the idea was for shooting living tissue (game animals) not paper targets. My assumption was that using quality bullets I would not likely be giving up practical field accuracy, and just maybe be gaining a smigeon of killing power. After all a achange from 1 in 12 to 1 in 8 is a 50% increase in rotational velocity if muzzle velocity is the same.
Member NRA, SCI- Life #358 28+ years now!
DRSS, double owner-shooter since 1983, O/U .30-06 Browning Continental set.
17 December 2006, 18:42
ALF/
17 December 2006, 19:41
tiggertateI bow to your knowledge about rifle projectiles but I have had more than one tragic instance of having divers die from shock waves from explosive detonations (hydrogen generated from underwater oxy/arc cutting that detonates if allowed to pocket behind the structure being cut). I suppose I was wrong to assume that a rifle projectile can generate enough shock to do the same.
"Experience" is the only class you take where the exam comes before the lesson.
17 December 2006, 19:54
ALF/
18 December 2006, 13:19
Gerardquote:
hmmm, this one will cause a stir... as the bullet slows, the rotation doesn't slow proportionally...
quote:
Posted 18 November 2006 22:51
With expanding mono bullets:
As the bullet penetrates and mushrooms, the forward velocity decays at a far greater rate than the spin rate. Evidence of this is in the fact that the petals of expanding monos are folded back at an angle greater than that of the engraving of the bullet.