Home Forums Hunting & Shooting Ask The Gunwriters Two Tipped TSX's recovered in a row

True.

OK...I haven't had my coffee yet...but why not?

Seems to me a bullet going 3000fps at a 12 twist rate on impact wouldn't matter if it was a foot or a five hundred yards from the muzzle....



I'll check back when I wake up....

Because bullet spin slows down VERY slowly, while velocity slows down pretty rapidly.

A bullet started at 2000 fps from a 1-12 twist is spinning at 120,000 rpm when it hits something near to the muzzle, say some test media meant to see how much the bullet will expand downrange.

A bullet started at 3000 fps from a 1-12 twist starts at 180,000 rpm, and is still spinning almost that fast when it hits something out where velocity has dropped to 2000 fps.

OK.

Thanks, Im glad you were the one to clarify for me, cause not everyone has your ability to uh....clarify.



So why doesn't rotational spin slow down as fast?



And how do we know this? Who measured it?

Not being contentious....just wondering what kind of degree/job you'd need to be 'that guy'....

What John said.

Tom,

I dunno who first measured it, but you can actually see the difference in spin-rate in bullet test material. In clear gel the rotations can be seen in slow-motion video.

The reason rotation slows down far more slowly than velocity is there's far less air friction around the entire bullet than there is on the front of the bullet.

I was told there'd be no math...

There's always math, especially when you least expect it....

I was looking for a new signature line. Thanks JB

Also that the bullet's forward motion displaces air, while its rotational motion does not.

It's often easier to picture projectile motion in water than air. Imagine the resistance you'd feel trying to push a cylinder through water as opposed to simply spinning it about its axis in water.

It has been a few years but Winchester pushed the "buzz saw" effect of the earlier black talon and SXT rounds as "terminal ballistic advantages". I do recall seeing the clear gel shots and it was obvious there was something going on. But as I am sure someone will point out, how much spinning is going to go on as a bullet passes through an animal?

I believe the MP went from a 1-16 to a 1-12 twist but could not confirm it anywhere. I do know the added twist kept bullets much straighter going through glass. With the slower twist there will be a distinctive square edge on the lower side of the glass indicating the bullet tipped at impact. Going to a faster twist kept a much better wound track with less deflection.

Some years ago several of us were doing a lot of bullet testing in the wax of The Test Tube, a fine product that failed on the market due to underfunding by the major backer. Bullets left a permanent "wound cavity" inside the tube, and the spin of the bullet was obvious in the cavity.

The most curious aspect was with TSX's the rate of spin in the cavity increased as the bullet penetrated deeper, but in the cavity from standard bullets the rate of spin remained the same throughout. In fact, with most bullets you could measure a complete turn in the cavity, and it would perfectly match the rifling twist of the barrel it was fired from: If the barrel's twist was 1-10, then the bullet would spin one turn in 10" inside the wax. But if the bullet was a TSX (or any other "petal" type bullet) the rate of spin increased throughout the wound channel.

One of us thought this might be due to the "propeller" effect of the petals, since in an expanded TSX they're typically slightly tilted like the blades of a propeller.

Most interesting! So theoretically, game shot at longer ranges would experience more twist per distance penetrated as the bullet sheds velocity, but maintains twist?

David

That IS interesting and may help explain a little why Im getting excellent accuracy out of the 55TTSX in a 1 in 12...which they don't recommend.....

Or it could just be magic.

I can't help but wonder if it's because the Barnes maintains its weight and velocity better as it travels through the medium,maintains a consistent expanded frontal area,while conventional bullets lose weight and momentum as they are torn apart.

Good thought Bob.....

Mike378 proposed a theory to me 25+ years ago that the speed of penetration had a bearing on the frequency of speed kills. I saw that after he proposed it in the earlier X bullets which I started using in 1990.

I also saw it in very light for caliber bullet weights such as the 100gn in .270 and also at longer ranges of say 600 yards with 53gn .224's fired from the .223 Remington.

The face of an expanded petal has a ridge line that provides an additional cutting platform as well as the propeller effect JB raised.
I have never seen or used synthetic testing medium but was fortunate to learn from flesh and bone which was a help also in the unlimited volume of culling which helped to learn this.
John

Not a lot of experience with the original X, or TSX, but enough to cause some doubts. I shoot more black bears than any other big game.

Perhaps 20 years ago, I shot a big blackie (app.400 lbs) behind the left shoulder at 95 yards (over bait in dense forest) with a 200gr X in .35-cal/Whelen. MV = 2800 fps. It was edge of dark. The bear took off and was never seen again. Next day 3 of us spent most of the day searching. I found a blood splattered area in dense underbrush about 75 yards from bait. The bear evidently spent night there. It left when we arrived at about 7am next morning. After that, only pin prick droplets for a couple of hours that led us into an endless swamp. Then nothing.

5 years ago, at the same bait location, I shot a medium bear frontally, under the chin as the bear was facing me at 93 yards. The rifle was my CZ550 in .458 Win Mag loaded with the 350 TSX (a moose load) at 2750 fps MV. The bullet impacted center front chest and made exit in flank of right side just in front of hip. That bear was found 40 yards from bait, but it had made a rather wide semi-circle on its escape route. In evaluating matters after the fact, and in the gutting process, I believe that bullet never expanded.

Why? Because I've shot too many bears with a .45-70 in the same location, and elsewhere, to know without any doubts that a flat tip, heavy cast or cup and core bullet will drop them on the spot, even without any major breakage of bones or CNS hits!

Just one "For example": Rifle: NEF Handi Rifle; bullet = 465gr hardcast with a 1/4" meplat. MV = 1900 fps. Range = 70 yards. Conditions: 3-foot tall grass and wooded area. Bait on edge of woods. I was in a treestand. Bear came to bait and I could only see head and neck in the tall undergrowth. Another frontal chest hit. The "trophy quality" bear disappears in the tall weeds and grass. He was literally flattened on the spot. The "thawak" was heard by a neighbor 350 yards away, and he said to himself:"Either he hit a large tree or the bear".

The bullet was never found, never expanded, and buried itself somewhere under the bear as it made exit at the bottom of the sternum. But -- there was massive blood loss internally. Not much show on the outside though. I've had the same and similar experiences with plain jane cup and core flat tips from a .458 Win Mag and other .45-70's.

I've never had a bear disappear after being wacked by cheap cast or cup-n-core bullets from any .45-70 or .458 WM. I've never lost an animal to anything that shoots bullets in .458".

I can't say that about the X though.

Yet, this past bear season (Sept - Oct), my Ruger No.1 .45-70 Improved was loaded with the 300 TSX in hopes of better performance. But I never got a chance to try that combo as the bears didn't cooperate.

Bob

www.bigbores.ca

Well that seems to kill the RPM theory mentioned above.

If a bullet started out at X RPM, but then lost velocity much faster than it lost RPMs, shouldn't a 1-10 twist rifle look like a faster twisted gun at impact?

What you're telling me is what Ingwe initially thought: a bullet fired out of a 1-10 twist gun makes a complete revolution once for every 10 inches it travels the entire length of its trajectory, losing RPMs at the same rate as velocity.

BTW, I'm not trying to be argumentative. Maybe I don't understand physics very well...