I have a question about bullet expansion that I'm scratching my head on. The bullet is a .308" 125 grain SST. I personally shoot this bullet out of my Rem 700 bolt gun in 300 blk out. I'm pushing it right at 2350 fps in a 16" barrel. ALL the animals I have shot have had perfect bullet expansion with 1 of 2 results. 1- the bullet exits and leaves a nickel to quarter size exit showing nice expansion. 2- the animal catches the bullet on the off side under the skin. The bullet is recovered and shows a perfect text book mushroom shaped expansion. Most bullets exit, but I'm happy with either outcome.

Now, we load this same bullet in a 308 Win with same 125 grain SST (3102 fps and 3080 fps range in several 308's), and we are getting complete pass through's showing zero expansion on multiple critters. The 308's are our night hunting rigs with thermal scopes, and we have taken numerous coyotes and several pigs. All the coyotes showed zero expansion with .308" size exit holes. Several pigs had complete pass through's right behind the shoulder showing no expansion either. All critters died and most went straight down like Thor's hammer. I love this little bullet, but I can't explain why zero expansion.

So how am I getting perfect expansion at a slow speed in the blk out, but zero expansion at the faster speed of the 308 Win? It goes against my logic, which is why I'm scratching my head. We are planning on loading up some 125 grain Ballistic Tips next to try.

That exactly the opposite of my expectations. I know that’s no help to the subject but I’m hoping you or someone else will come in with an explanation shortly.

I have seen similar results with early ballistic tips in my 270. The exits were small. After field dressing several and finding a lot of fragments and intense internal damage I came to the conclusion they were a typical approximately caliber sized entrance rapid expansion and a small remaining part of the bullet or the lead core, or possibly base of the bullet would exit leaving a small exit wound. In all my shots with them no spine or shoulders were hit, straight through the ribs lung shots and none of the deer ran a step, which tells me there was a lot of shock or internal damage done.

Also saw something similar on a buck my wife shot a few years ago with a 150 grain nosler partition. She hit a cattle panel square on before the deer I found the jacket with rear core intact just under the off side skin and a small approximately caliber sized exit that left very little blood. I believe the front core exited.

Right there with you...


I have a few thoughts
1) time in animal. The bullet moves through the animal before it can expand

2) not enough counter force- there is so much momentum on the bullet that there is not sufficient force to create expansion

3) black magic. The hunting gods are unhappy with your choices

4) bullets construction. Something about the bullet is not right. Bad batch or couple of bullets

Redchevy has my guess-front of the bullet is exploding, leaving the base to pass thru?

Shoot some phone books or gel packs and see what happens, Chad?

Chad,
I’m sure both calibers are fully expanding. Your slower bullets are tumbling after they expand, hence creating larger wound channel than the diameter of the mushroom. I would guess that if you measured the diameter of a recovered, fully mushroomed bullet, it would be far smaller than the diameter of a quarter. The “Thor’s Hammer” effect is hydrostatic shock from a faster bullet...(I almost always get that effect from my Barnes triple shocks, which is why I shoot it in all my rifles).

If the bullet is not expanding when shot in the 308, which seems almost impossible to me, then an autopsy is needed. If the bullet really didn’t expand, internal damage won’t be extreme. If the insides are destroyed, as you’d expect, then it must be the remains of the bullet exiting.

I bet your contacts at Hornady know and can tell you....but I'm with Cleric...I think it's #3.

Either the bullet fragments badly and the exit is made by the bullet base, or something about the impact is preventing the bullet from deforming as designed, possibly preventing the expansion cavity from contacting fluid matter.; thus no hydraulic expansion.

This goes right in line with what I've said about Berger VLD-Hunting bullets. Those that don't like them, ran fairly light for cartridge and they were moving very fast. Explode, no exit, animal ran off. My 7 Rem Mag is running 180's at 2950 fps MV. A friend of mine is running 210's out of a 22" .300 Win Mag at 2780 fps MV. Each of us love those VLD's, no complaints.

It seems ultra fast does not work as well as when you slow them down a bit. I am suspicious of the reaction time of tissue, and time in the animal as mentioned. Why can we punch a hole in 1/2" AR 500 with a .223, .22-250, 22 Creedmoor, ect, but not punch a hole in the same steel, at the same distance with a .300 Win Mag, and a 210 gr coming out around 2850 fps, having significantly more energy? Speed tears up steel, we know. There is something to that with tissue. Super fast needles through.

Everyone pretty much knows I run about every rifle with a heavy for cartridge bullet, and what animals I hit go to the ground. But, I can't put my finger on the exact physics as to why.

You don't say



Next thing you're gonna tell us is you're left handed

I have shot enough stuff with a 90 grain .277 hollow point or a 100 grain .277 soft point at 3300-3500 fps to know they don't pencil though, I think it has to be a function of something different than speed or time if they are truly not expanding. Someone smarter than me explained it once on here before, but in general more speed should equate to more expansion given same medium of impact and same construction of bullet.

After my wife shot a small doe with a 7 mm (7x57) 150 gr Partition at approx. 2800 and we saw blood, hair and guts exit , the doe ran off never to be found. I called Nosler and was told it was completely possible that the partition did not expand with the small body doe and the speed of the bullet at 100 yds. Take it for what it's worth.

Punk

Partitions are the best hunting bullet ever made, with over 6 decades of proven performance. This isn't bullet failure, it's poor shot placement most likely. I've put 7mm partitions in way over 150 big game animals, and when put in the proper place, the animals died rather quickly whether here, Africa, Mexico, or wherever.

I don't like to talk about it.... but we lost our first critter with a partition this season, one loaded by me . Brother shot a does behind the shoulder, heart lung. Text book shot reaction. My dad had a good buck on the ground already so he didn't wait at all got straight down and walked to it. At the edge of the grass line he walked up on the doe down it jumped up and ran left good blood for a bit then ran out and no more. He could see the shot on the deers side when he jumped it. Our place is covered in brown grass 3-5 foot tall, so there is a very real possibility they just didn't find it, but searched long and hard and the next day and never found it. Now im going to burry that deep inside and not talk about it again.

I have seen this ... my guess is two different twist rates. I would hazard that the 300 BO has fast twist rate and 308 has slower causing different expansion rates.

There is no magic bullet.

But there ARE silver bullets!

And those make everything better.

I bet you're getting core jacket separation. Lite bullet pushed fast. Small piece exiting.

Jgraider, You need to learn how to read! Read my post again, nothing was said about big game from Africa or other parts of the world. Just a small doe from east texas. Who is a person to believe you or a Nosler bullet technician?

I guess you missed the point. At least you took it like a grown up.

Funny you ask this. I saw a man who had never saw a bullet tell the man who made it and owns the company that he questioned his information. After all this is the internet.

Punctuation is friendly.