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M 16 and M4 Civilian Variants

Junkball

"I believe in ammunition"
pilot
Very early rifles had barrels with a 1-14 rifling twist rate but I believe all the ones we had were 1-12. The 55 grain bullets we used would barely stabilize at 1-12. It wasn't that uncommon to have rounds keyhole in a paper target at 500 yards. That said if you were any good they would keyhole in the black. That combination of a 55gr bullet and a 1-12 twist barrel was what gave the M16 it's well deserved rep for doing nasty shit to another human. For man killng out to 300 yards, an M16A1 loaded with 55gr rounds in a 1-12 barrel gives me a woody.

I've read several times that the earlier rifling pattern was the cause of the great lethality of the M16A1. I understand the -A2 was designed to increase accuracy and the new twist was for compatibility with the Belgian NATO round, but it's supposedly like hitting a target with a .22 caliber ice pick. With all the reports of shooting people 3-4-5 times (Mogadishu anyone?) and them getting back up, why haven't folks looked into destabilizing the bullet as a means of increasing the lethality of the 5.56 round?
 

mmx1

Woof!
pilot
Contributor
I've read several times that the earlier rifling pattern was the cause of the great lethality of the M16A1. I understand the -A2 was designed to increase accuracy and the new twist was for compatibility with the Belgian NATO round, but it's supposedly like hitting a target with a .22 caliber ice pick. With all the reports of shooting people 3-4-5 times (Mogadishu anyone?) and them getting back up, why haven't folks looked into destabilizing the bullet as a means of increasing the lethality of the 5.56 round?

http://ammo.ar15.com/ammo/project/term_tighttwist.html

Um, no. The wounding potential of the 5.56 comes from the bullet yawing in tissue and fragmenting as the jacket fails. Whether this happens is primarily based on the velocity of the round and its construction than its spin rate. OTOH, destabilizing the round will lead to longer bullets tumbling unpredictably in air (not sure if this is what you're getting at).

The twist rate's been progressively increase to stabilize longer bullets, first from 1:14 to 1:12 to stabilize the 55gr M193 in cold (dense) air, then to 1:7 to stabilize the 62gr M855 and particularly the really long M856 tracer round.

The main contributor to the degraded terminal performance of the 5.56 is the move to shorter 14.5" barrels in the M4, which doesn't have as much muzzle velocity, and roughly halves the range at which the bullets will reliably fragment.
 

Bevo16

Registered User
pilot
Words and a link


^^^^all true, but only applicable with FMJ rounds. We don't have to follow the Geneva Convention here at home. One distinct advantage of civilian AR-15's to Government M-4's is the ammo we can use. Get a box of this and solve your expansion issues:

Satellite
 

Rocketman

Rockets Up
Contributor
http://ammo.ar15.com/ammo/project/term_tighttwist.html

Um, no. The wounding potential of the 5.56 comes from the bullet yawing in tissue and fragmenting as the jacket fails. Whether this happens is primarily based on the velocity of the round and its construction than its spin rate. OTOH, destabilizing the round will lead to longer bullets tumbling unpredictably in air (not sure if this is what you're getting at).

The twist rate's been progressively increase to stabilize longer bullets, first from 1:14 to 1:12 to stabilize the 55gr M193 in cold (dense) air, then to 1:7 to stabilize the 62gr M855 and particularly the really long M856 tracer round.

The main contributor to the degraded terminal performance of the 5.56 is the move to shorter 14.5" barrels in the M4, which doesn't have as much muzzle velocity, and roughly halves the range at which the bullets will reliably fragment.

As always hard science and research trumps 1970's folklore.

Just to be clear, we weren't taught that a slightly un-stable round was more deadly because it was tumbling before it hit flesh. We were taught that because it was slightly un-stable it would upset and tumble easier/quicker after it hit flesh. It always made sense to me though because I knew that it didn't take much to make that round swap ends. A stray blade of grass would sometimes make a round keyhole in your target.

Fragmentation is a different issue to be sure. I love the idea of short barrels on AR's but also know they decrease velocity which as you say decreases fragmentation range. In my little world that's not a big deal because my AR will never be anything but a toy or maybe a home defense weapon. If I ever shoot someone in self defense beyond fragmentation range I'll have bigger problems than a round that didn't fragment.
 

DangerousDan

I could tell you but I would have to kill you
Rocketman,
Just wondering if you know if century arms is any good since they are in your neck of the woods.
 

nittany03

Recovering NFO. Herder of Programmers.
pilot
None
Super Moderator
Contributor
Rocketman,
Just wondering if you know if century arms is any good since they are in your neck of the woods.
Century is hit/miss. I have a PSL from them that I like quite a bit, but they've also been known to mix crap in with the good stuff. That said, I had what I think was a hot surplus load jack up the recoil assembly on said PSL, and they still replaced it promptly under warranty.
 

Rocketman

Rockets Up
Contributor
Century is hit/miss. I have a PSL from them that I like quite a bit, but they've also been known to mix crap in with the good stuff. That said, I had what I think was a hot surplus load jack up the recoil assembly on said PSL, and they still replaced it promptly under warranty.

Nittany is spot on. I'm not sure they would actively rip anyone off but at best buying cheap AK variants, mil surp and C&R weapons on line can be a crap shoot anyway. I have seen them jack prices around a bit more that I think is reasonable but that's just me. If you buy a problem from them I think they would make it right.

I'd have no problem buying most of what I see up on their site today as long as the price was ok and I realized that a Hungarian AMD-65 is what it is no matter who you buy it from.

I live about 10 miles from those guys and used to go by and hand pick surplus rifles and AK's. Now they don't allow walk in's. Lucky for me the FFL I deal with ($15 transfers) goes by every Friday to pic stuff up for his customers. I order ammo and now and then a weapon from Century online and pick it up from the FFL on Saturday.

If anyone lives in the Charlotte area and needs a good FFL PM me and I'll hook you up.
 

FLY_USMC

Well-Known Member
pilot
On a different subject but similar, what's with these arseholes selling bone stock no BCG 10.5" LMT Uppers for $655 when you can buy the damn things new for $495? Price gouging chaps my ass....I ordered one from LMT direct and I don't care how long the damn thing takes to get to my house, 6 weeks or 6 months, but I'll be damned if I'm going to pay some mother f'er 1.5X what he spent on something he just got in the mail. Same thing goes for PMags....I laugh that now they are in stock, you can get them for their original price of $14-16 and dumbasses with 100 of them are still trying to get $20-25 for them. I ordered 15 of them like 3 weeks ago for $14.65 a piece with the window...internally I was laughing my ass off.
 

Rocketman

Rockets Up
Contributor
On a different subject but similar, what's with these arseholes selling bone stock no BCG 10.5" LMT Uppers for $655 when you can buy the damn things new for $495? Price gouging chaps my ass....I ordered one from LMT direct and I don't care how long the damn thing takes to get to my house, 6 weeks or 6 months, but I'll be damned if I'm going to pay some mother f'er 1.5X what he spent on something he just got in the mail. Same thing goes for PMags....I laugh that now they are in stock, you can get them for their original price of $14-16 and dumbasses with 100 of them are still trying to get $20-25 for them. I ordered 15 of them like 3 weeks ago for $14.65 a piece with the window...internally I was laughing my ass off.

Me too and I have a long memory when it comes to that kind of crap. Especially with mags and ammo.

There are others but AimSurplus stays consistant and as does 44mag where I try to buy most of my mags
http://www.44mag.com/prodinfo.asp?number=MAG211

This last years price gouging has exposed several vendors and put them on my NEVER buy from list.
 

H60Gunner

Registered User
Contributor
Anyone who purchased a lower from this auction receive one yet? I have not, and even though it is still May and the auction stated a guaranteed delivery by June. ??
 

Rocketman

Rockets Up
Contributor
Anyone who purchased a lower from this auction receive one yet? I have not, and even though it is still May and the auction stated a guaranteed delivery by June. ??

I ordered 2 and did so expecting them no sooner than when ever they get here. There hasn't been an update on the website since March and that says June/July.

I will probably give them a call in late June if I haven't seen or heard anything else. I believe the company below is where the are shipping from.

http://www.shop.thesecondamendmentfirearms.com/product.sc?categoryId=16&productId=39
 
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