I’m getting 2280 with my hand loaded 77gr smk. Is that going to be enough velocity and energy for expansion to 200yds?
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I’m getting 2280 with my hand loaded 77gr smk. Is that going to be enough velocity and energy for expansion to 200yds?
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https://www.thefirearmblog.com/blog/...n-5-56mm-ammo/Quote:
Originally Posted by TFB
SMK isn't great for terminal performance anyways...nor was it ever intended to be.
Barnes TSX 70gr has an expansion threshold of 1800 fps that might be worth looking at...
Any of the Barnes TSX bullets could work with their 1800-1900 fps expansion thresholds. Just remember that the 50gr “Optimized” bullet loaded by Black Hills is not a standard TSX. It’s proprietary to Black Hills and needs more speed for expansion, 2300fps sticks in my mind. It is also not available as a component.
Some factory loads that I’ve tested in my 10.5“ Noveske give the following velocities. I am sure you could hand load and get equal or greater speeds, especially with an extra inch of pipe. And I think all of these would give you expansion to 200 yds.
Winchester Ranger 65gr Bonded. 2599 fps (An FBI load)
Hornady 75gr TAP SBR. 2206 fps
Federal LE223T3 62gr. 2757 fps (An FBI load)
Barnes 5.56 62gr TSX. 2638 fps
Black Hills 5.56 50 TSX optimized 2815 fps
Black Hills MK262 77gr OTM 2430 fps
Federal Fusion 62gr. Expansion threshold seems to be 1700 absolute minimum.
Will easily get you to 200 yards in a 10.5" barrel factory loaded, so you'll be good past that with an 11.5" barrel.
https://youtu.be/otou1Fws4cQ
At close, open air ranges with ample velocity , it's a happy accident... when it happens.
Sources (just off the top of my head):
Sierra bullets
Snipercraft
Press check Consulting
Gary Roberts
Numerous industry ballistic demo's
Forge Tactical
FBI sniper school and pretty much every LE sniper school
And a few years of shooting stuff and seeing for myself and drawing my own conclusions
thanks
...and yeah, I get that the military has "stacked bodies" a plenty with Mk262, M118LR and other cartridges with SMK bullets, and there are some boners out there who swear by them for hunting as well.
It's the same 6.5CM vs. 308 debate...which is better (rhetorical)? Superior external ballistics with reduced terminal ballistics for better shot placement OR lesser external ballistics for the hope of better terminal performance?
...just getting that out there. As many of us have the free choice to choose exactly what we need for the task at hand (at least we were when ammo was more widely available)
Granted MK262 isn’t my first or second or third choice. But if it’s all I had I wouldn’t fret.
I always though Mk262's claim to fame is increased accuracy and range, which leads to increased kills.
55gr FMJ and OTMs are MILES apart in frag. I've shot gobbs of gel and water tests over the years with many bullets. I've downloaded 77s to transonic (1450+/- here) and they didn't frag, but never anything to simulate velocity drop at a few hundred yards.
And now I have to do it. We'll get the chrono and the Gel jugs set up in the next few weeks. Try to get around 2000 fps say???
You cant lump all OTMs is the same boat. The SMK design tends to have a longer neck length than the noslers or hornady OTMs thus is less prone to fragmenting putting it closer to FMJ performance than any of the other OTMs comparatively.
Pointblank dropped a gem of knowledge that passed over everyones heads. Some of the sources he listed actually shot people with Mk262 and were less than impressed which correlates to professional gel testing showing that Mk262 isnt as good as OTM TAP, Mk318 or M855A1. Yet we want to trust shooting jugs as some kind of metric. Im all for more data and have done jug testing myself but trying to make conclusions from jug testing other than "will it or wont it" isnt useful.
I didn't realize this thread was in the Terminal Ballistics section, or I wouldn't have posted. But anyhow... rather than download 77s, I think I'll take a 10.5, put a scope on it, and shoot the gel at 200 yards with a SMK 77 gr OTM.
I'll be massively shocked if the bullet fails to frag.
Can't see how it wouldn't be. OP was asking about the expansion threshold of a bullet that was never intended my the manufacturer to have expansion properties. It's purpose built as a match/target round. Fragmentation was not a design feature.
If you want 100% fragmentation of the 77SMK, shoot some car windshields ;)
This just popped up on new posts. I assumed it was ammo/reloading
I shot a bunch of rounds into windsheilds. Nothing 556 gets through nicely. I think this was back before bonded was commonly available though.Quote:
If you want 100% fragmentation of the 77SMK, shoot some car windshields ;)
While we're on the frag waggon. Here's the last one I shot a few weeks back:
87 gr BARNES OTM/Black Hills. (fragged so bad this is all I could find)
https://i.imgur.com/VGomK0D.jpg
Excellent expansion and higher retained weight than the lighter gold dots or other bonded SPs. Works well out of short barrels and long barrels. Low velocity but I wont be shooting very far with it.
https://www.youtube.com/watch?v=2lkI36eUoy4
Have you checked POI shift between the Gold Dot 78s and TMKs? I have a bunch of 64 gold dots, but don't mess with them due to the big weight swing from 77s that almost always gives me a significant POI shift.
For me factory BH 77gr TMK always shoots 2-3" higher using a 50yd zero using different barrels(left or right shift will depend on your barrel). Granted it has a ~150 fps advantage out of a 14.5" but I bet if you loaded the 75gr GDSP to the same velocity the vertical shift due to velocity would be minimal.
Ubet, maybe you could bump up your velocity ? I know BH is king but, We got 2,508 fps out of Black Hills factory ammo out of a 10.5 barrel. God and BH's only knows how they do it and maybe not get BH velocity but I bet you could get a bump.
On the other hand, that may not interest you. Good luck.
I have the 64grain GD on my HD weapon.
PB