FMJ yaw and upset performance

[Variable]

Up late?LOL

I realize you are here to refute something you disagree with regarding the 6.8, but since this is the Grendel board and I have no interest in the 6.8----

Which Grendel rounds do you think would have the most "ideal terminal performance"?

Any gel shots?

[DocGKR]

Well, working at a Level I Trauma Center often results in somewhat unusual hours...

This week someone asked me about the misinformation posted in this thread regarding our initial SPC testing, so I thought it might be prudent to provide the correct facts.

Some of the characteristics of an ideal performing general purpose rifle projectile have been described in recent government wound ballistic meetings and in commentary by SSA Buford Boone of the FBI BRF:

-- Penetration of 12 to 18 inches
-- No impact AOA induced variations
-- Blind to barriers
-- No deviation from shot line after impact
-- Minimal fragmentation
-- Consistent terminal performance from 0 – 300 meters
-- Sufficient accuracy to hit threat targets out to 600 meters

Assuming properly prepared, calibrated, and sized gel blocks, I'd be supportive of any Grendel load that meets the criteria listed above and offers barrier blind terminal performance, as depicted below:



Keep in mind that “Barrier Blind” ammunition should demonstrate minimal changes in terminal performance between unobstructed shots into bare gelatin and those obstructed by intermediate barriers.

[JASmith]

Good information!

I am one of those who knows that, while the 6.5 will be sleeker than the 6.8 for equal bullet weight, the terminal performance magic is in bullet design. The potential exists independent of caliber.

From that point of departure, one next looks at both near-in or under 300 meters -- several cartridges in this size class will deliver over these most common engagement ranges, including both the 6.5 and the 6.8. The next is to ask the question "Is the combination of muzzle velocity and ballistic coefficient for those well-designed bullets to be adequate in terms of drop and drift to get high hit probability out to 600 meters?"

Independent of where one's heart lies, the 6.8 bullets launched by the SPC tend to lose velocity with the attendant drop and drift issues compared to the 6.5 in the 300-600 distance. To be sure, the differences aren't large, but they exist.

Of course, one can pack a few more SPC cartridges in the mag -- but this may not matter out in the deer or hog hunting arena.

[Variable]

I am one of those who knows that, while the 6.5 will be sleeker than the 6.8 for equal bullet weight, the terminal performance magic is in bullet design. The potential exists independent of caliber.

I agree. That's why I was wondering if he had anything to contribute about the Grendel. I know he was involved in 6.8SPC testing, but I believe only very limited 6.5 useage. I just wish someone who was in a position to test things had the Grendels interests in mind once in a while, instead of just the SPC. Not impugning GKR, by the way, just stating that he hasn't been very involved in Grendel stuff to my knowledge. I guess that if we pooled money and paid someone to do the testing then we'd get our great looking gel shots eventually, but no one has ever stepped up to the plate.

I really doubt that the 6.8SPC projectiles are imbued with any magical terminal performance qualities that couldn't be readily duplicated in a 6.5 projectile with a tweak or two. Some of them probably already fit the bill. I know they sure do a fine job of killing anything I've ever aimed them at.LOL

The 6.8 crew has always been driven to promote their package as being suitable for .mil adoption, and torwards that end they have produced some good data and good looking gel shots. No one on the Grendel reservation has dedicated nearly that much time nor resources toward the same end. I'd just like to see the same amount of effort expended behind the 6.5, but since the Grendel makers seem to be doing fine in the commercial market without it, they've never been motivated to do so.

Oh well, I guess.... Maybe someone will one of these days.

[stanc]

I agree. That's why I was wondering if he had anything to contribute about the Grendel. I know he was involved in 6.8SPC testing, but I believe only very limited 6.5 useage.

AFAIK, the only 6.5 Grendel load in official tests was 120gr SMK.

I just wish someone who was in a position to test things had the Grendels interests in mind once in a while, instead of just the SPC. Not impugning GKR, by the way, just stating that he hasn't been very involved in Grendel stuff to my knowledge. I guess that if we pooled money and paid someone to do the testing then we'd get our great looking gel shots eventually, but no one has ever stepped up to the plate.

Yup.

I really doubt that the 6.8SPC projectiles are imbued with any magical terminal performance qualities that couldn't be readily duplicated in a 6.5 projectile with a tweak or two.

I think that depends on the type of bullet. Any expanding bullet optimized for 6.5 Grendel ought to give terminal performance indistinguishable from the same make and model as for 6.8 SPC. Evidence of this can be seen in the tests of 6.8 SPC 110gr TSX and 6.5 Grendel 120gr TSX:




However, for projectiles that depend on yaw, such as the FMJ in the subject title, it appears to me that the short 6.8 bullets tend to yaw more quickly than the long, streamlined 6.5 bullets. This is evidenced by the gel tests of the Remington 115gr 6.8 FMJ and Norma 120gr 6.5 FMJ. I'm skeptical that such 6.5 bullets can be tweaked enough to match 6.8 yaw ability.

The 6.8 crew has always been driven to promote their package as being suitable for .mil adoption, and torwards that end they have produced some good data and good looking gel shots. No one on the Grendel reservation has dedicated nearly that much time nor resources toward the same end. I'd just like to see the same amount of effort expended behind the 6.5

Ditto. But, I won't mention my "Testing, Testing" thread. :eek:

[stanc]

RUAG military rifle ammo:

http://www.ruag.com/de/Ammotec/Armee_und...Forces.pdf

I found particularly interesting the illustration near the top of page 5, showing the lead-free 5.56mm LF HC SX FMJ bullet expanded like a hunting hollowpoint. Unfortunately, it doesn't say what was the target medium.

On page 11 is the French-designed 7.62mm lead-free AP bullet.

[txgunner00]

Pretty cool. If it performs like that in human tissue it may have better terminal effects than M855.

[Variable]

RUAG military rifle ammo:

http://www.ruag.com/de/Ammotec/Armee_und...Forces.pdf

I found particularly interesting the illustration near the top of page 5, showing the lead-free 5.56mm LF HC SX FMJ bullet expanded like a hunting hollowpoint. Unfortunately, it doesn't say what was the target medium.

On page 11 is the French-designed 7.62mm lead-free AP bullet.

I'm curious about the LF HC SX as well. When I zoom in on the pic I can't tell if it's a digital rendering or an actual picture. It looks kinda digital, but it might be real. I would expect they had to score the jacket to get it to peel like that if it really does. It'd be darn interesting if so. I'm surprised they'd market something like that with the old continents political sensitivities being as they are...

The french bullet looks interesting as well.