Doc or anyone who might know more about the subject at hand,
Any idea what the terminal ballistics of the 165gr and 175gr loads mentioned would be like when fired from a 12.5" barrel? Do you have an estimated effective range on such a rifle/ammunition combo? I know it’s a pretty broad question, just trying to get an idea here.
With this, the 12.5" HK417 and SCAR H CQC come to mind. The advertisd muzzle velocity for the 12.5" HK417 with 175gr M118LR is 709 m/s (2,326 fps). Would one be able to load such rounds to achieve higher velocity without overpressure issues or is that typically a no no?
I have an HK51 with an 8.3" barrel. I did some un-scientific testing. I shot large 40 gallon water jugs with various rounds to see what would happen. XM193 55gr. 5.56mm rounds would penetrate, on average, 22" and reliably split into two fragments along the canneleure(sp?). 110gr. Hornady TAP .308 would penetrate 20" and completely fragment. I know that its not supposed to matter, but the 5.56mm rounds would cause just a tiny ripple on the water surface while the .308 rounds would actually explode the containers.
Recoil was light from the HK51. Muzzle flash at night with the TAP ammo wasn’t bad at all with an HK flash hider. No more than an M14 shooting ball. Surplus ball ammo was a fireball.
“Any idea what the terminal ballistics of the 165gr and 175gr loads mentioned would be like when fired from a 12.5” barrel?"
Yes, some idea.
“Do you have an estimated effective range on such a rifle/ammunition combo? I know it’s a pretty broad question, just trying to get an idea here.”
It will likely have no fragmentation potential by 200 yards and just yaw over. In general, the 175 gr SMK has better terminal effects when impacting above 2500 fps. Below is a 175 gr SMK hitting at 400m when fired from a 24" M40A1:
The whole reason why loads such as the 155 gr TSWG OTM and 130 gr Mk319 Mod0 were developed is for use in shorter 12-16" barrel 7.62x51mm weapon systems–why would someone choose to use a 175 gr SMK in a .308 SBR when better options are available?
“With this, the 12.5” HK417 and SCAR H CQC come to mind. The advertised muzzle velocity for the 12.5" HK417 with 175gr M118LR is 709 m/s (2,326 fps). Would one be able to load such rounds to achieve higher velocity without overpressure issues or is that typically a no no?"
You would NOT likely be able to load to higher pressures and still have a durable weapon system, not to mention keeping propellant pressures within reasonable levels and stable at environmental extremes.
Doc, do you have by any chance any data on the German 7.62x51 ammo?
This is all I could find:
Bullet design is AB22 whose terminal ballistic performance in tissue is unique from most other 7.62 NATO FMJBT Ball bullet designs. Rather than pitching up 90 degrees, then pitching backwards another 90 degrees and exiting backwards, AB22 pitches up 90 degrees then breaks into two parts at the cannelure, similar in performance to M193 5.56 NATO Ball.
Source: http://www.afte.org/forum/smf1/index.php?topic=1574.msg22903#msg22903
Wow! It seems not all steel jacket 7.62 NATO ammo is created equal… sadly the germans changed their bullets on purpose, to avoid fragmentation.
DocGKR, what is the reason the DAG ammo fragments at much lower velocities (=extended ranges)? Thinner jackect?
Have you tested this bullet?
What is the bullet weight and velocity (they should comply with the NATO standard)?
What is the performance of this DAG ammo against common intermediate barriers, compared to gilded metal clad bullets?
It seems that bullets like this present a very cheap and simple alternative to enhance terminal ballistics in this caliber, are there any downsides?
I would guess the gel testing and redesign of 7.62x51 NATO bullets with thin steel jackets was undergone in the early '90s… before that, in the '80s, this fragmenting behaviour was well known but not widely understood.
The Danish performed tests in 1992, and changed their AMA bullets in 1995, and the fragmentation threshold was about 2345 fps, pretty low! I think other countries investigated this subject and made changes before the danish.
note this comment, typical reasoning for the changes:
"This behaviour is assumed to be due to a lack of strength in the jacket causing it to break at the cannelure when hitting the target at high velocity. The fragments will increase the already sizeable lesions and may leave the body through several separate exit wounds, presenting problems, both for the surgeon treating survivors and for the forensic scientists when defining the direction of the shot. The legality of this and similar bullets in view of the Hague Declaration of 1899 may be questioned, and we feel that the bullet should be redesigned. A programme to this end has been initiated by the Danish state owned ammunition factory."
There is no indication, in the german army ammunition data sheets, that the bullet design was changed (1992 to 1996).
Unfortunatly i do not have any newer or older data sheets.
The Bundeswehr released a video last month about a wound ballistics workshop for military and civilian medical personnel on their official youtube channel. At 2:25 Mr. Kneubuehl explains how the german 7.62 x 51 bullet behaves. As the bullet tumbles, it breaks at the cannelure in half and produces two exit wound channels. It’s clearly visible in the video. No further details or data (velocity etc.) is mentioned.
I hate to bump a 7 month old thread, but I didn’t feel starting a new one would be appropriate.
Am I correct in assuming that terminal performance would be similar or identical, even with different 7.62mm projectile designs and weights, once you get out to longer ranges (600-800m)?
If that’s the case, does barrel length play a significant role in wounding potential at long range? From reading the above quote, I’m inclined to believe that even from shorter barrels (12.5"), terminal ballistics would be similar once you reach longer ranges, no matter what barrel length you started with (12.5" to 20").
Terminal performance at longer ranges is going to be quite similar. Starting with a longer barrel/higher velocity will help your external ballistic trajectory and drift, but not terminal ballistics much beyond 300-400.
