Hornady GMX warning

[KurtR]

if im shooting mono its through both front shoulders to break them down and expansion seems more consistent

 

[SDHNTR]

I’ve shot several truckloads of game with GMX bullets. They guys that are saying to shoot into the shoulder have it figured out. That’s key.

 

[BooneAK]

Thx, all! I, too, reached out to Barnes and got the same numbers, but only for a couple bullets, so thx to sndmn11 for the detailed reply. Take away—use Barnes TTSX. No reason at all to use GMX. If you have to talk about switching out of the killzone and going to the shoulder just because your bullet won’t expand at standard velocities in soft tissue, you’re driving with the check engine light on. Not only that, but what happened to the ethos of quick kills?

 

[Mosby]

Barnes are consistently the most accurate bullets in my rifles. I prefer the TSX and the LRX.

 

[hodgeman]

Here are tested minimum FPS IMPACT velocity to achieve consistent 1.5x diameter expansion for Barnes bullets I inquired about. These are direct from Barnes.

Use those numbers with a big grain of salt. Expansion testing is done in calibrated gelatin...it's not that closely calibrated to critters.

If a guy wants to use monos...get the speed up as fast as you can and put some meat under it for resistance for best results. None of the monos really expand all the great once the impact velocity drops off at longer range, so the GMX isn't likely all that different than E-tips or TSXs or Trophy Coppers.

I did use some 125s TSX in my .308- they worked pretty well but the rifle didn't jive with them.

 

[sneaky]

I don't care about feelings when it comes to bullet performance. I care about expansion, bullet integrity, and penetration. And most of all, I care about lethality, which is what our beloved wildlife deserves. I also might have gotten sucked in by the marketing.

I shoot .308, which along with .30-06, has killed more of everything than all the other calibers put together, but I like them, too, so let's not get into it. .308 is not a rocket in terms of velocity -- we all know that -- but it works.

Last year, I killed a beautiful caribou bull with Hornady's Outfitter GMX in .308, 165 gr. Who doesn't want water-proofed primers and weather tough cartridges, right, with 95% weight retention and 1.5x expansion? But at 400 yards, those bullets went through that bull and left pencil holes. It took three shots before he fell over. That happens sometimes, and I was and am still thrilled, but I'll never use GMX again.

Look at the data I've attached from Hornady's catalog, and you'll see why. Is a .308 generally thought of as a 400-yard capable rifle? No doubt. (Do I want to shoot farther than that? No.) But look at the velocities of the Outfitter at 400 yards (1881 FPS) compared to the 2000 FPS expansion. No wonder I got pencil holes.

Call Hornady tech support and ask them what the minimum velocity is to get 50% expansion. They don't know. They'll say that the velocities for the .308 GMX bullets (150, 165, and 180) all range from 2300-3600 FPS. OK. Where did that 2300 come from, and if that's reliable, corresponding to some level of expansion on that end of the velocity spectrum, are you telling me that the .308 is only a 150 yard rifle, because that's what their own tables seem to suggest. Follow?

So, if you use GMX, make sure you're getting enough velocity to get the kind of expansion we all want, like Hornady shows us below at 2700 FPS or higher for .30 caliber, and that's going to exclude a lot of calibers at a lot of ranges with GMX bullets. For as much hype that goes into marketing 95% weight retention and 1.5x expansion, you'd think manufacturers -- for the sake of the welfare of wildlife -- would be eager to share what minimum velocities are required to actually obtain whatever percentage expansions and not make us make the inferences.







View attachment 279106View attachment 279105

I've had Berger VLD Hunters pencil through more deer than any monos I've used. It happens with everything at some point.

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[Joelweb]

Seems like you are using the wrong cartridge if you plan to shoot that far with mono-metal bullets. I use the GMX in my 280 Ackley and it kills with authority.

 

[HuntHarder]

Thanks for sharing OP. I am glad that you learned from your mistake. Shooting copper monos require either good velocity or hit something solid. If neither of those are achieved, you will almost always just pencil thru. .308 was developed long before all copper bullets were prevalent. I would say that cartridge is underpowered to achieve high expansion at that range.
Anyone else remember when 400 yards was considered a long shot? How times have changed.

 

[fwafwow]

There’s really not any homework to do. It has a recommended impact velocity on the box as well as estimated velocity’s for the cartridge the buyer is using. Seems pretty cut and dry. Box says 2050 FPS at 300 yards and shows minimal expansion at 2000 so logic says keep shots under 300 yards. Seems hornady makes it pretty easy and clear.

I purchased a handful of boxes of 90gr GMX Superperformance rounds for my 25-06 and admit to having done so not following research, but because they were available. I have not shot any yet, and this thread got my attention. So I looked at my boxes and may have missed the recommended impact velocity - I just saw some "CA compliant" label and a muzzle velocity, but no other speeds. The Hornady website didn't make it obvious (at least to me), but with a Google search and digging out the ballistics PDF, I've figured out I'm probably good with my rifle and these rounds out to ~400 yards to still be at ~2000 fps.

 

[lifeisgoodsteve]

Interesting. Honestly, as a newer hunter I have done so much research on so many things, but I do admit that when I bought my first non-lead bullets, the Superformance gmx, I was ignorant of velocity for expansion. So many layers to the hunting onion for sure, but all good and fun evolution.

For reference from actual experience with the GMX, here's a pic of the Superformance 6.5cm GMX bullet I recovered from a 400 yd shot on cow elk. Per Hornady site, looks like it should have been traveling 2249fps on impact.

Quartered away, shot through lungs and stuck under skin on opposite side. It probably ran about 50 yards before toppling.

 

[KurtR]

Thx, all! I, too, reached out to Barnes and got the same numbers, but only for a couple bullets, so thx to sndmn11 for the detailed reply. Take away—use Barnes TTSX. No reason at all to use GMX. If you have to talk about switching out of the killzone and going to the shoulder just because your bullet won’t expand at standard velocities in soft tissue, you’re driving with the check engine light on. Not only that, but what happened to the ethos of quick kills?

Shooting the front shoulder is the kill zone. And don’t get to excited about the tsx if you don’t hit bone you will have the same thing happen. If your wanting to shoot behind the shoulder cup and core bullets are a much better choice.

 

[willfrye027]

Here’s a federal blue box copper bullet, 30-06 impact velocity around 2000 fps. Shot through the brisket recovered in the offside ham. Shot him again through the high shoulder as he ran 75 yards down the hill and stopped after the first shot.

learned my lesson about monos and impact velocity.

 

[Formidilosus]

Here are tested minimum FPS IMPACT velocity to achieve consistent 1.5x diameter expansion for Barnes bullets I inquired about. These are direct from Barnes.

.264”/6.5mm 127 gr LRX- 1600 fps

.284”/7mm 139 gr LRX- 1400 fps

.284”/7mm 145 gr LRX- 1600 fps

.308” 175 gr LRX- 1600 fps

.308” 190 gr LRX- 1500 fps

.308” 168 gr TTSX- 1500 fps

.308” 180 gr TTSX- 1500 fps

.308 165 gr TTSX- 1800 fps

You’re not getting anywhere close to 1.5x expansion at those velocities from those bullets.

 

[Formidilosus]

Use those numbers with a big grain of salt. Expansion testing is done in calibrated gelatin...it's not that closely calibrated to critters.

That’s not true at all. Properly calibrated ballistics gel has the highest correlation to performance in tissue of any media. If you know what to look at, it’s near one for one.

 

[sndmn11]

You’re not getting anywhere close to 1.5x expansion at those velocities from those bullets.

I thought it was realistic for the diameter to go from .308 to .462, that's only .08 on each radius.

What do you think is a realistic expectation?

 

[Glendon Mullins]

So a shoulder shot isn't a kill zone shot? damn i been doing this all wrong for 30 years!!

 

[Formidilosus]

I thought it was realistic for the diameter to go from .308 to .462, that's only .08 on each radius.

What do you think is a realistic expectation?

With most of the TTSX’s you listed, you’ll be fortunate to get anything more than caliber sized expansion below 2,100- 2,000fps unless major bones are hit. LRX about the same down to 1,800’ish.
You can not judge how well a bullet performed its job by what it looks like when you pull it from an animal for multiple reasons. Mainly, that if you recover a mono from an animal it generally means that either the projectile impacted significant resistance (bone) or traveled through tissue a long ways (angled shots). In both cases, the expanded diameter is the Maximum size at the end of its travel in low velocity impacts. Most people would be very unpleased if they saw what a mono looks like while it penetrated a chest cavity.

 

[mauserfan]

I believe that bullet shape is a large factor into how these bullets work at the target. For many years we have shot the Barnes 150gr FP in a .30-30 and the performance is more than impressive on large Whitetails. WE are also shoulder shooters.

 

[PathFinder]

I'm not sure why the OP is upset; you got exactly what you bargained for. Slow caliber, and a poor expanding bullet. Results were exactly what physics dictates they should be.
But weight retention was so high, isn't that what matters?

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[brushape]

I live in California and get into this argument with every fanboy creedmoor shooter almost daily it seems.


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