5.56 Water Expansion Testing; 55/70gr GMX, 62gr TBBC, 55/64/75gr GDSP
Did some water jug testing today. Please do your own research about this as it is NOT a tissue simulant. However, it is good for comparative purposes. All shots delivered from my 16" BRT Optimum 1:8 5R duty rig except for the last shot, 6) Speer 55gr GDSP, which was from my buddy's 16" middy 1:7 BCM CL'd upper. All shots were fired from approximately 15 yards, without a chrono, at 80 degree F ambient temperature. Rounds were tested today in this order:
1) Hornady 55gr Superformance GMX 5.56 NATO pressure
2) Hornady 70gr GMX TAP (only made in 5.56 NATO pressure)
3) Federal XM556FBIT3 62gr TBBC (5.56 pressure FBI Load)
4) Speer 64gr GDSP (.223 pressure)
5) Speer 75gr GDSP (.223 pressure)
6) Speer 55gr GDSP (.223 pressure)
A half pallet was used. 5 1-gallon water jugs were used for each shot. Penetration and effects description:
1) 55gr GMX NATO Superformance. fully split the first two jugs; just literally ripped them completely in half. Heavily damaged the 3rd jug. Punctured and was captured in the 4th jug.
2) 70gr GMX TAP. fully split the first two jugs. Same as 1). Partially split the third jug (heavily damaged; more so than 1 or 3). Bulged and partially seam-split the 4th jug. Penetrated 4th AND 5th jugs and was captured in the 5th. 5th jug was flipped over onto its back.
3) 62gr XM556FBIT3. fully split the first two jugs; just literally ripped them completely in half. Heavily damaged the 3rd jug. Punctured and was captured in the 4th jug.
4) 64gr GDSP. fully split the first jug with a connecting piece of plastic on the bottom. Partially split the second jug. Captured in the third with little to no damage.
5) 75gr GDSP. fully split the first jug with a connecting piece of plastic on the bottom. Marginally more damage to the second jug than the 64gr above. Captured in the third jug with same amount of damage as above.
6) 55gr GDSP. Fully split the first jug with a connecting piece of plastic at the bottom. Bulged the second jug and dented the back wall, but was captured in the second jug.
General observations:
The effects from the 70gr TAP GMX were notably better than either the 55gr GMX or the vaunted 62gr TBBC. Another shot was taken with a 165gr Remington Hog Hammer TSX from a 16" Faxon barrel in an AR10 I built for my buddy. Not super dissimilar performance from the 70gr TSX for the first 3 jugs. However, no slug was recovered.
Both the 62gr XM556FBIT3 TBBC and the 55gr GMX NATO Superformance performed identically. Which is to say that they were both very impressive. They were head and shoulders above the GDSP rounds in terms of their effects on the first three jugs; both penetrated into the 4th jug (both of them knocked the fourth jug over onto its back side). It was even clear to my terminal ballistics neophyte buddies that the first three rounds were clearly in another league compared to the Gold Dots... and that their increased price did indeed net observably superior performance in both penetration depth and terminal effects on the first three jugs.
The over-expansion of the lighter 64 & 55gr GDSP bullets was easy to see, with this acutely affecting the 55gr. Though, this may make them particularly well suited to SBR use.
The 75gr GDSP had solid performance and was clearly the strongest recoiling .223 pressure round tested. Again, without a chrono reading I cannot comment intelligently on the actual velocity. But it felt strong.
Pictures of expanded rounds in next post....
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5.56 Water Expansion Testing; 55/70gr GMX, 62gr TBBC, 55/64/75gr GDSP
Quote:
Originally Posted by
ALCOAR
I guess we'll have to agree to disagree. Documented means just that, tests or occurrences showing where it's failed fwiw.
Nonetheless, I wanted to present a counter argument to your assertation that Hornady GMX loads were head and shoulders above the GDSP loads in the context of actual self defense for those that might read this thread in the future. It's up to them to then research expert opinions on this matter like Dr. Gary Roberts to make up their own mind on this subject.
Still no.
I've been carefully studying Doc Roberts' body of work since before his first NDIA presentation. I don't get lectured on his work.
Further, you seem blissfully unaware that there are occurrences of literally every single modern projectile design failing to perform as intended. However, in careful consideration of our delicate casual or neophyte readers, the impression created by your statement that these occurrences are statistically relevant to the discussion are dangerously incorrect.
In clear terms of the overall percentage mass lost through auto glass, there is very little mathematical difference between homogeneous solids and bonded lead core projectiles; they both lose mass when traversing barriers such as laminate auto glass. Further, the occasional shedding of petals has not shown to have a meaningful difference in terminal effectiveness after the barrier aside from increasing penetration by an inch or two. With notable exceptions like the USMC SOST non Bonded round by federal/atk.
Lastly, you have not accurately stated my assertions. And they don't need restating; see my original posts.
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5.56 Water Expansion Testing; 55/70gr GMX, 62gr TBBC, 55/64/75gr GDSP
Quote:
Originally Posted by
WS6
Velocity IS a wounding mechanism at 1800+. It contributes greatly to secondary projectiles as well. As a matter of fact, this doe (shot with 70gr gmx by me at 78m) had secondary projectiles all through the top 3" of her lungs from her spinal column. Further, expanded bullet shape, etc. Does matter. A large flat meplat will destroy tissue more than a rounded one. Especially at the latter portion of the wound tract. My ra556b at 27m (pix on harddrive, not phone) produced significantly less damage than my 70gr gmx at 23m, from a shorter (14.5 vs 16.1) barrel on the exit side. Very interesting about bullet shape, weight, etc.. the wounds look like they cam from different caliber weapons, and you can see the value of retaining velocity through the target. Lots of blood trail on the 70gmx, none really on ra556b.
Attachment 54678
Attachment 54679
Vicious, I'm tracking.
WS6, THAT is what I experienced with the 70gr GMX even from my SBR. Granted, I bought almost all my 70gr GMX at one time, early in their initial release. But, I see explosive wound tracks with the occasional punctuate entrance, always a silver dollar or bigger exit, and always guts and blood and organs blown out of the backside of the animal. Blood trail is always strong, even when I tagged a 285lb boar through both cartilage plates and both scapulas at about 40m. Frankly, that didn't look much different from my Tikka T3 shot at 70m on a 240lb sow with 308 Winny 165gr Federal Trophy Bonded Tip (a TBBC with a boat tail and ballistic tip). Effects on the animal were the same; a quick dirt nap and some squiggling in place.... which quickly ended.
Granted I'm not equating the two calibers. Not hardly (I just spent serious coin building my own AR10). But the effects I'm seeing from the 70gr GMX are slightly better than with the 55gr Superformance GMX and the 62gr TBBC (neither of which would I hesitate to use for hunting or SD/HD). The farm I used to hunt at mistook my hogs for hogs my buddy shot with his Romanian AKM clone using 7.62x39 Wolf soft point and Hornady soft point on more than one occasion while they got started dressing the carcasses from the truck beds.
The guides who occasionally came out to hunt/spot with me commented that, when fired from my 11.5" suppressed SBR, the 70gr GMX created an audible "thump"/thwack that made them think it was a 7.62 AK round or a 6.8. Purely anecdotal. But they are all seasoned guides and not prone to praise. More like merciless mockery on a constant basis.
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