Question regarding 55gr,70gr GMX/TSX and TMK SMK barrier performance.
While doing research between the 55gr 70gr BARRIER GMX TAP (not the super performance load),I noticed on Hornady’s website the 70gr is said to meet fbi requirements but the 55gr does not have any such description on the ballistics information page. It seems that the 55gr penetrates deeper, has better cavity depth and terminal performance. I wanted to know if the 55gr GMX BARRIER TAP meets FBI ballistic testing. Basically for performance from 100y out to 350y. Which of these two BARRIER TAP loads would be the better performer?
This is my first post on this site. I have been very heavily involved in researching and enjoying the information in the forums.
-Thank you everyone for building such a great community.
My other question was in regards to the mk262 TIPPED SIERRA MATCHKING (TMK Blackhills load) Will this round still be able to hit a ballistic target inside of a vehicle. To what degree will the SMK and TMK actually perform against barriers. It seems people make it seem like it’s not cable at all if there is a barrier in between you and your target. What can I expect from the SMK and TMK when engaging a vehicle with ballistic gel inside various points? (forward into front auto glass, side windows as well as through the paneling on the vehicle.
I really want details as I am going to be going out to my friends property to do some testing with all of the rounds listed in my post. I just want some help from the community here as far as what I am going to be experiencing.
-Thank you- Ryan M
My thiughts:
50 gr tsx optimized (black hills load) will be the best all around.
Don’t know about the 62 gr optimized.
77gr tsx will perform well. The petals tend to shear off through glass/steel.
Smks frag through glass resulting is very shallow penetration. If I was planning on defending myself through glass, these would rank low on the list. For most other shots, they perform very well. Hard to beat for an HD to long range outdoor use.
To know the true performance, you’ll want gel behind the glass. Water jugs will give you an idea and is better than nothing. Looking forward to it!
Great, I appreciate the informative response. I am still confused about the ballistic gel performance on Hornady’s site. It pretty much said that the 55gr GMX penetrates better compared to the 70gr. Does this mean the 55gr is better all but at long range?
I think the 70gr GMX is going to be a good deal. The GMX bullets are “more durable” than the TSX bullets, and shouldn’t shear petals/lose much mass through auto-glass or other harder barriers, while still expanding very well on soft tissue.
The 55 grain gmx looks like it didn’t expand and that’s why it penetrate more. Besed on the gel shots, I’d go with the 70, but the 55 looks good. I think the gmx loads will fall in right under the 50 gr optimized BH tsx. We’ll see though.
The price of the TSX is just isnt practical for practicing unless xm193 would have the same POI. doesnt the 55gr GMX have the same POI as xm193 or does the length of the copper weight to length ratio make it more on track with 62gr loads?
I really want to know how ineffective mk262 or TMK which is advertised as having better barrier performance then the original mk262. Could you still hit a target behind a vehicle through the front windshield with the TMK and get a hit?
This. It’s not about hitting a target, it’s about being able to stop a threat on the other side, which means it needs to still be able to penetrate enough tissue to reach and penetrate the vitals.
I don’t know how they calculate perm cavity, but the temp cavity is a wounding mechanism for rifle rounds. That said, die tends to make it look better than it is. The 70 showed significant vertical cracking along the wound channel, which I would think is a good thing, but can say for sure. I’d like to hear an experts opinion on that.
I’ve been looking for a good barrier blind round to use in my patrol rifle so I’m interested in what your testing shows. I think I’ve settled on the GMX, just not sure which one. What barrel length will you be using?
You can’t really ever go wrong with choosing the heavy-for-caliber projectiles, all other things being equal. Better Ballistic Coefficient, which translates to Improved External Ballistics and Energy down range… and they almost always penetrate deeper, while starting out with more mass, so if it happens to shed some weight, you’re still better off than starting out with a lighter weight projo.
Not saying it’s completely wrong to use a lightweight bonded/solid barrier blind load… but just my thoughts. Hits are always better than misses and all that jazz.
5.56 is still a Turd Burglar compared to basically any other Centerfire Rifle round when it comes to Intermediate Barriers.
Ok here is where it gets a bit difficult to think about…55gr GMX you get a decent increase in velocity and the 70gr has a bit more weight. so how you do calculate the difference in penetration taking into account the increase speed of the 55gr when impacting compared to the slight increase in weight at a slower velocity with the 70gr. I am speaking of a limit of 350MAX range.
I just went shooting 60miles south of Seattle yesterday with my first ar15 build. It really made me realize why the 5.56 is used over 6.8. I can keep the Iron sights on target no matter how fast I shoot. It is such a reactive and controllable caliber. The 6.8 kicks you off your irons enough to slow down your reaction and the 6.5 isn’t enough of a step up to justify the ballistic needs in urban environments, tho it would be useful as a sniper round even tho there are better options in this department. So I feel the 5.56 is the best urban center fire round available given my experience with accuracy and control while shooting my ar15 mil spec clone.
The all copper loads like the GMX 55gr among others penetrates barriers to a degree that is very effective from my personal tests. The GMXwhen hitting a hard object clips the tip together so it doesn’t expand allowing the round to break the barrier and induce yawing once flesh is impacted on the other side of the barrier. So I disagree that it is ineffective against barriers. given the control of muzzle climb it is an amazing rifle. An added plus is that the ammo would still have value if the economy were to even destabilize. all of the special ar calibers and even the 308 would be very hard to come by in such a situation. 5.56 is the way to go for my needs.
for urban use copper solid, gilded and bonded rounds make up for it’s barrier performance issues that are only present with the fragmenting rounds that were set as the staple load for the rifle. This might have just been a mistake that is being corrected now that we have seen so many developments in the ar15 systems capability.(excluding mk262 like rounds that are used for extreme range engagements) The rifle we have in this day in age is of no comparison to the older varieties.
I am crossing my fingers that no one brings up the “it was designed to wound” myth in this post. lol
and of course the 55gr GMX is actually an affordable gilded copper round and has the same poi as xm193. Cant go wrong with having practice ammo that has the same POI as the 55 GMX. I hope they don’t ban xm193 now that they have caused this 855 panic…ugh, not that its even a good load haha.
I never said the 5.56 was “Ineffective” against barriers. Please point out where I said that. However, I did say it was a Turd Burglar compared to basically any other center fire rifle cartridge, when it comes to Interdmediate Barries… that’s a True Statement with Factual Evidence.
Also, calling Mk262 “Extreme Range”… hmmm, no further comments.
