More On 5.56mm Ballistics
BY Herschel Smith
6 years, 10 months ago
This video is interesting given my almost obsessive interest in ballistics.
In it he analyzes the performance of the bonded soft point in ballistics gelatin, and his claim for superiority of this round is that it expands (like a soft point does) but it is more “barrier blind” than other rounds that are not bonded soft point. It stays together and intact through barriers.
But take a look at the wound track in the gelatin. It’s pretty straight and doesn’t fragment, and one of the things we know about the 5.56mm round is that it yaws upon tissue entry and fragments. This is one of the aspects that gives it its lethality in spite of the small bore.
Compare that now with what you see in this ballistics test using M193 (there are a thousand like it, and also of the M855). Compare and contrast the wound channel and fragmentation. Which ammunition would you prefer for personal defense in close quarters battle?
|
|
On February 12, 2018 at 7:36 am, Jack said:
Off Topic, but it looks like auto-correct got the better of your post… would = wound…
Or is this the result of copious amounts of cough and cold medicine?
On February 12, 2018 at 9:41 am, Herschel Smith said:
Thanks for the correction Jack. Fixed.
On February 12, 2018 at 9:53 am, Fred said:
“This video is interesting given my almost obsessive interest in ballistics.”
As long as you don’t become compulsive about it! (smile)
On February 12, 2018 at 2:39 pm, moe mensale said:
If his concern is for a load specifically for short barreled rifles then I’ll stick with Hornady’s 75 grain TAP SBR, #81295. It’s an expanding, not fragmenting, round and shoots very well out of my 10.3″ Colts.
As far as M193, that’s reserved for the 20″ Colts were velocity is king.
On February 13, 2018 at 11:10 pm, Peteypete said:
Federal 62 grain Tac Bonded from a 10.5 inch barrel @ 2576 fps results in 17.6″ of penetration & retained weight of 61gr with max/min expansion of 0.468/0.399 inch with final projectile shape being mushroom (through gel only). There was no bisection of the test media for high detailed inspection as with the XM193 comparison data, however, for this 62 gr the wound channel appears to widen/deepen dramatically beyond 1” with both max width/depth occurring in the 3-7” range of penetration then reducing in width/depth at 9” to a narrow channel for the remaining 8.6”. This bullet comes to rest at a 60-70° spire elevated angle from horizontal in the gel block. Note: at the 4:32 mark a very small fragment is visible in the test media at a depth of 3.5 inches, this is likely the 1.0 gr mass fragment.
XM193 55 gr from a 16” barrel @ 3086 fps/1163 ft lbs through two layers of drywall (simulated residential construction) into multiple layers of 1 gal plastic water jugs results in the projectile penetrating simulated drywall essentially intact as well as entry side of the initial water jug with quick and heavy fragmentation in the exit of jug #1 and continued fragmentation in jugs #2 & #3 with what appears to be no damage to additional jugs (#4-6). In the 4 layered denim covered gel this round penetrates the 4 layers of denim intact, the wound channel shows significant fragmentation starting at the 4-8” range in multiple directions, the permanent cavity has max width of 3” and max depth of 5”, however the temporary wound cavity is ~8” x 8” which appears as both larger and more uniform than the Federal Tac Bonded 62 gr. The 55 gr BT largest segment 44.7 gr penetrating to a max depth of ~12.6” and yaw is as expected with bullet coming to rest at a 45° angle with boat tail forward retaining 44.7 gr indicating fragmentation of 10.3 gr total mass in multiple segments.
If effectiveness = lethality then yaw induces more damage (trauma) via both temp/perm wound cavity, larger and concentric large diameter shock waves, and fragmentation. More trauma theoretically correlates to more lethality. Note: significant increase in performance with controlled pairs (WSTIAC). However, lethality is not always necessary to achieve the objective (WSTIAC).
It would seem CQB application effectiveness, in fact, is lethality. The 55 gr with yaw and fragmentation, combined with a larger/more concentric wound cavity provides for more effectiveness. The 12.7” penetration depth after 4 layers of denim also meets some widely accepted “standards” for other small arms of 12-18”. Additionally the drywall simulated residential construction penetration/fragmentation of water jugs #2 and #3 (estimated 10-18” after residential drywall) would also be more effective than the 61 gr mushroom with no yaw and very minimal fragmentation penetrating well over 17”. Note that data for 62 gr performance through drywall was not included in the study.
Your thoughts?