7mm-08 120gr Nosler BT - massive difference in performance?

hartster

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Feb 21, 2019
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G'Day

I have joined this forum specifically to ask this question, so please go easy on me!

I have experienced very mixed results from two shots for two deer, with the 7mm 120gr Ballistic Tip shot with a 7mm08 at 2990fps. This bullet was loaded by a relative who ordinarily I trust implicitly but I suspect there is a mistake... so does he.

On a ~2 year old red deer (equivalent to a reasonable sized young mule deer buck), shot into the top of the heart from 175m, the bullet has over-penetrated and under-expanded, producing a very narrow wound channel, a slow bleed, and a long runner, with a calibre sized entry wound and an exit wound of less than 1/2". The animal was recovered after a fast run of over 200m, requiring a 2nd shot after he finally lay down. In the over 35 years of hunting I have never seen a deer run that far and take so long to go down, when shot through the top of the heart, where the main aorta and pulmonary arteries join the organ, plus such limited peripheral wounding of the lungs.

On a second deer of the same size, shot in the identical body position a few seconds after the first deer, the bullet has over-expanded, totally fragmented and not exited. It obliterated the top of the heart and pulped the lungs. Several mug fulls of thick red goop in the ribcage. We found lots of very small fragments of jacket and lead, but did not find the bullet base. The deer expired after taking 2-3 steps, 5 seconds tops.

No major bone was involved in either impact, both bullets took out a rib on the way in. When we inspected the chest cavity both points of impact were as close to the exact same position as it is possible to be, same rib, same height above the brisket.

When I questioned this performance with my relative he confessed that he may have mixed up "new" design 120gr BTs with "old" design 120gr BTs. Now obviously that is a bit of a disaster when it comes to reloading practice, so let's move on from that, and concentrate on what changes there were to the bullet design that could possibly create such a massive difference in performance. They are all in a box labelled Ballistic Tip Hunting, #28120. However some of the bullets are plainly a lot older (tarnished copper).

I have spent a couple of hours googling this and have some information that suggests the more modern ballistic tip design is a much tougher bullet then the old design. I have read on another forum, that somewhere on this forum, there have been cutaway photos posted to show the exact differences in the two designs, but I can't find them.

For my own interest and as a way to explain what I have experienced with these bullets, can anyone point me towards a resource that can show me precisely what the differences are? I am expecting differences in jacket thickness and base design, but nothing beats a direct photographic comparison. Not looking for a debate on which design is better, I have a very clear preferred bullet construction for shooting deer in our kind of environment, and that's never going to change.

Here's hoping one of you wise fellas has got something that can point us in the right direction.

Thanks in advance.

PS if I don't reply soon its because I am about to go off on a two week hunt in an area with no signal, I will be following up on this for sure.
 
Welcome aboard, Hartster. Good to see your post. I shouldn't imagine that anyone will give you grief. It sounds as if your relative has likely diagnosed the cause of the results you observed. The 120 grain BT as manufactured now is a stout bullet, to be certain. However, I would expect it to expand very nicely. It is not a particularly frangible bullet. The first shot sounds more like what might be expected if no bone was encountered during terminal performance. There are several threads that pictured the newer bullet, though I don't particularly recall the older bullet being sectioned.

I envy your hunt for red deer. Though I haven't hunted them, I do hunt mule deer (and whitetail), elk and moose. I've used a .280 for each of these critters. My first .280 used 139/140 grain bullets (Hornady SP, Nosler BT and PT). All provided me with quick, clean kills at the velocities I used (~2850 fps).

Someone may be alone shortly to point you to the appropriate thread to display what you are asking. Again, wishing you every success in your hunt.
 
Thanks Dr Mike. Yes bone was definitely encountered on the first strike, a small hole through the middle of an incoming side rib. In contrast, the second strike shattered not just the rib it hit but did minor peripheral damage to the adjacent ribs and created an entry hole considerably larger than the first strike.

I'm sorry I haven't got the photos at hand, I really wanted to post with photos as it tells a very clear story, the contrast between the two deer. I doubt I'll be able to get my hands on them before I go away in the morning. But at some point I'll get hold of them hopefully.
 
Giday to you too! Can we assume you are shooting these deer in Aotearoa? Having shot lots of them over the years with both the .270/130gr BT and 6.5x55/139gr Normas I did not find them particularly
hard to kill with either caliber. However your findings
really do surprise me, as the 7/08 should be about a "perfect caliber" for the Red deer??? I am going to guess it must have been a "bad bullet" but who knows.......... I would have thought something around
140gr a more likely candidate for a big stag? Much better BC on a long shot, stabilize better in your barrels twist? Deeper penetration on a angled shot?
Anyway great to have you onboard! And do share any hunts from the land of the "Long White Cloud"
Ps. I lived in Wanaka for years. Wonderful spot.
 
I’ll agree with what’s already been posted as far as old and new bullets. As far as why your animal ran so far, I’ve seen absolutely weird stuff. A deer hit right on the shoulder with a .348 running through snow with absolutely zero blood anywhere except for a tiny trickle about an inch long out of its nose. Other deer hit in the same area had blood sprayed like it came from a garden hose. Sometimes it’s just weird.
 
The 7mm 120 gr BT is the only bullet that shares a jacket with another bullet, the 140 gr BT. It is cut down to the 120 gr profile which makes the jacket thicker at the tip. This is the reason why the 120 gr BT is such a robust bullet.

JD338
 
JD,
Thats great info on the jacket thickness, I didnt realize that! Thanks for sharing.....
 
Nosler120NBT.jpg

Found these sectioned 7mm bullets!! They say the 140 gr and 120 gr share the same jacket!! Looks different! With these jackets being extruded I don't believe the 120 is a 140 jacket that is trimmed down. Maybe the same blank just doesn't get extruded to the same length. That would answer why the jacket is thicker!!
 
At what date did the 7mm 120gr BT change design? I have a box that is probably 6 years old, and was about to load up some 7mm08 for my kid's use. After reading the above, it seems the newer 120gr BT are stouter, less frangible? I'm shooting 150-200lb when dressed whitetail in MI... not sure whether I'd be wanting the older bullets or the newer ones, after reading this thread.
 
PipesMac":2u09jubs said:
At what date did the 7mm 120gr BT change design? I have a box that is probably 6 years old, and was about to load up some 7mm08 for my kid's use. After reading the above, it seems the newer 120gr BT are stouter, less frangible? I'm shooting 150-200lb when dressed whitetail in MI... not sure whether I'd be wanting the older bullets or the newer ones, after reading this thread.

Over 20 years ago. If they’re 6 years old they’re good to go.

The ones you have are newer. Not a deer walking that’s safe.
 
I can attest to what SJB just typed. I saw what the 120 gr Btip out of a 7-08 did to a whitetail doe this past Sunday. I would trust it against any whitetail and muley for that matter.
 
Sweet, found 3 boxes of Nosler 7mm 120gr Ballistic Tip at Cabelas, hard to believe in the middle of this shortage. Also a box of 140gr BT. Grabbed them all, ready to start my load ladders and maybe a nice reduced load too. ;)
 
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