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1/22/2020 12:12:56 PM
Posted: 9/13/2009 5:57:43 PM EST
Ok, crew, I haven't chronoed my pistol yet, as I still need sights......any sights.... I was happy to see that it performed great today at the range, function wise.

We were talking about the loss of velocity due to the 7" barrel with the 5.56, and what the effectiveness of the round might be compared to a 9mm or .45acp 7" barreled upper. Can someone sum up the effectiveness of the 5.56 vs the 9mm or the .45acp?


Thanks!
Link Posted: 9/13/2009 8:45:32 PM EST
[Last Edit: 9/13/2009 8:48:23 PM EST by easy610]
There are much more educated folks around regarding ballistics and such but I can tell you I chrony'd 5.56 out of my 7" AR pistol and found with Q3131 I was around 2400 fps. That should frag pretty reliably. Not at 100 yards but within 30-40 yards? It should frag.

I feel it is superior to 9 or 45. Especially when considering ability to defeat armor and such...

Figure 9mm out of a 7" bbl will be around 1100-1200 fps? 45 probably only slightly less.

Bigger bullets, yes. But 5.56 has much more powder (frankly too much for a 7" bbl...hence the super cool fireball and report!). Both 9 and 45 are designed for short bbl firearms, read handguns.

Link Posted: 9/14/2009 2:55:57 PM EST
Good info. Thanks.

I wonder what the 5.56 would look like in ballistic media?
Link Posted: 9/15/2009 6:31:53 PM EST
Doesn't it require 2700 fps for fragmentation to occur? I'm seeing these and starting to get the itch to get one.

Link Posted: 9/15/2009 6:49:01 PM EST
5.56 out of a 7" barrel might also catch the BGs clothes on fire at close range.
Link Posted: 9/16/2009 8:39:39 AM EST
[Last Edit: 9/16/2009 8:46:01 AM EST by FIGJAM]
M855 and M193 will not fragment from a 7.5" barrel (not at 30 yards, my experience). They tumble and flatten a bit but don't come apart. That's with wetpack which is a pretty good simulator of dense muscle tissue.
Link Posted: 9/16/2009 3:55:23 PM EST
Will softpoints expand?
Link Posted: 9/16/2009 5:36:30 PM EST
Originally Posted By heat762:
Will softpoints expand?

I'd bet a good hunting bullet might; for sure a ballistic tip, but that may not penetrate enough......???
Link Posted: 9/16/2009 6:39:05 PM EST
[Last Edit: 9/16/2009 6:44:04 PM EST by FIGJAM]
Barnes TSX do at 50 yards and should expand to 200. Hornady TAP should expand as well.

The two at the bottom are M855 shot at 30 yards in to wetpack. The six above were shot at 30 and 50 yards.



Link Posted: 9/16/2009 7:01:20 PM EST
Originally Posted By FIGJAM:
Barnes TSX do at 50 yards and should expand to 200. Hornady TAP should expand as well.

The two at the bottom are M855 shot at 30 yards in to wetpack. The six above were shot at 30 and 50 yards.

http://members.cox.net/smashbang/FG.jpg




Very cool photo and info, FIG!
Link Posted: 9/16/2009 7:14:42 PM EST
varmit grenades.
Link Posted: 9/17/2009 4:09:29 PM EST
[Last Edit: 9/17/2009 4:13:27 PM EST by easy610]
Originally Posted By SRRhodesia:
Doesn't it require 2700 fps for fragmentation to occur? I'm seeing these and starting to get the itch to get one.



I've always read around 2500 is the threshold...below and you are getting less reliable. Around 2100-2200 fps, and no frag. Over 2500 and gets better and better.

As always, lets not compare apples and oranges. An AR15 pistol does not take the place of an AR15 rifle.

If going into harms way I would much rather be carrying one of my rifles...despite the fact that my AR15 pistol is a favorite gun of mine. I have realistic expectations.

If in CQB environ or traveling in a vehicle (read drivers seat), the AR15 pistol is a viable option IMO....

As for wetpack is is a very different medium from ballistic gel or human flesh. I have never trusted the results for accurately extrapolating what a round will do in a live creature...no offense.

But this is the interweb and you get what you paid for!

Cheers all,

**EDIT**

FIGJAM...what was the bbl length those were shot out of?
Link Posted: 9/17/2009 4:23:49 PM EST
7.5" WOA Wylde chamber. The Barnes were 62gr at about 2250 fps (5.56x45 load). The M855 was about 2310 fps.
Link Posted: 9/18/2009 11:55:43 PM EST
Originally Posted By FIGJAM:
7.5" WOA Wylde chamber. The Barnes were 62gr at about 2250 fps (5.56x45 load). The M855 was about 2310 fps.


Impressive.
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