Attn. Senior Members who know their stuff???

[ARCHIVED THREAD] - Attn. Senior Members who know their stuff???

Posted: 7/26/2001 10:40:45 AM EDT

I own four prebans. One in 308, one in 9mm, and two in 223. I just purchased a colt M4 flattop with 16" barrel with 1x9 twist. This is mounted on preban bushy. I own an HBAR that I probably will sell complete upper. I want to purchase another M4. My question is what config do I get? It will be another flattop. Do I get 14.5 with perm attached FS? with a 1x7 twist? Just for variations (real military config.) or another 16" with 1x9. Also, I got a vortex on my 16", what should I get perm attached to 14.5 if you feel it is a good choice. A vortex,phantom, Kurts A3 or gemtech bi-lock? I respect your opinions. Thanks. Do not be afraid to email me. Thanks a bunch guys!!!!!

Posted: 7/26/2001 11:29:56 AM EDT

[#1]

btt

Posted: 7/26/2001 11:42:41 AM EDT

[#2]

I don't know my stuff like others on this board. I don't have the knowledge or know the history of the M4 enough to give you advice in that area. I can only speak from experience.

So with that in mind, I have a Bushmaster M4 16" barrel with the A2 on it and couldn't be happier with it. This upper shoots excellent and I have never had a single problem with it. I personnaly prefer the 16" barrel over the 14.5" just for accuracy reasons but understand the difference isn't much.

I can say that if you are interested in putting a bayonet on it the 14.5" is the better choice as the ring on the bayonet fits right around the FS as to around the barrel on the 16". Which in all reality isn't how it's supposed to mount...

Good Luck to ya

Posted: 7/26/2001 12:02:18 PM EDT

[#3]

Quoted:
My question is what config do I get? It will be another flattop. Do I get 14.5 with perm attached FS? with a 1x7 twist?

View Quote

The purpose of the 1x7 twist is long-range accuracy, which really necessitates a longer barrel.

The design of the M4 is for portability, and short range high volume fire.

An M4 witha 1x7 twist is kinda like having screen doors in your submarine, IMO.

[:D]

Posted: 7/26/2001 12:03:19 PM EDT

[#4]

I don't think Senior Member means we have all the answers. I think it has something to do with the number of post's.

Now to answer you question, you have an impressive collection already. Why not get the one you like the best, not what the general consensus is. After all it's your money and your weapon. The beauty of an AR is, it can be as individual as the person that owns it. [smoke]

Posted: 7/26/2001 12:20:45 PM EDT

[#5]

I spoke with a fellow member by phone who specializes in class III weapons. I do not want to mention his name as I do not have permission to. I want to say upfront I trust his comments to me. He says that the 1x7 is what the military uses to assist in the impact of flesh affect. And, that the military found the 14.5" to be the perfect size. His products come directly from Colt and are products made FOR the military. These are uppers only.
If I wanted to stay USGI for one of my M4's, I was thinking this config. unless I am convinced otherwishe. Thanks again.

Posted: 7/26/2001 12:33:34 PM EDT

[#6]

Quoted:
He says that the 1x7 is what the military uses to assist in the impact of flesh affect.

View Quote

How dramatic!!!
The 1/7 was used to stabilize the
longer, heavier M856 tracer rounds.

Posted: 7/26/2001 12:40:31 PM EDT

[#7]

I know stuff.

If I had the money (which I don't and probably never will) I would get the 14.5" Colt or Bushmaster (chromed lined barrel) and a Vortex (Sommers, not a knock-off).

Posted: 7/26/2001 12:40:59 PM EDT

[#8]

You're buddy is wrong about the reason for the 1in7 twist. It was adopted to stabilize the very long tracer bullet currently in use, and that the only reason. Unless you're planning to shoot current issue tracers, a 1in9 or 1in8 twist will give you equal or better accuracy, and probably longer barrel life. That's why these twists were introduced in the first place.

Course, I'm not a senior member (yet), but I'd say that 28 years of AR15 ownership and recent retirement as armorer for the security force at a government agency might give me some credence.

Posted: 7/26/2001 12:41:22 PM EDT

[#9]

Originally Posted By garden weasel:

Quoted:
He says that the 1x7 is what the military uses to assist in the impact of flesh affect.

View Quote

How dramatic!!!
The 1/7 is to stabilize the
longer heavier M856 tracer rounds.

View Quote

I second that. I read somewhere that the M856(?)tracer round's ideal rifling was 1/5 and the M855's is 1/9, so the compromise was 1/7. Anyone else here anything like that.

Posted: 7/26/2001 12:44:24 PM EDT

[#10]

Can a bullet be destablized by a rifling ratio that's too fast?

Posted: 7/26/2001 1:25:34 PM EDT

[#11]

My suggestion:

Get an [green]Armalite[/green] M15A4(T) upper in pre-ban config (if you are going to put it on a preban).

Also, get a Jewel trigger.

Should be a tack driver! [:)]

Posted: 7/26/2001 4:05:42 PM EDT

[#12]

Mrp,
Why armalite? Just curious. I feel that most of you agree that it is best to go with a 1x9 twist and that probably would be found only in a 16". Is that right? Also, Vortex over phantom correct? Thanks guys.

Posted: 7/26/2001 4:30:44 PM EDT

[#13]

Bullet length (and density) determines the rifling twist needed for stabilization. If one is dealing with pure lead (or pure anything) longer also equals heavier.

M856 Tracer is stable with 1/7. I've not seen tumbling tracers, even in cold weather. Something tighter might be more accurate. Tigher twist, however, creates more wear -- no free lunch. Faster twisting motion means more strain and friction. 1/7 is a compromise to produce as close a trajectory match between M855 and M856 as possible. Tracers are suppose to show where Ball is going.

For non-tracer firing 1/9 seems to be the "universal twist" and is kinder on the barrel. Most match shooting seems to be 1/8 twist.

Assuming the bullet is stable in air (no M855 from M16A1 1/12 twist please), the rifling twist has no effect on the bullet's stability once it enters heavy media such as water or animal tissue. Bullet tumbles right now! By the time the bullet has penetrated 4" it's tumbled 90°. 4" distance is a microsecond in time. [I'm sure someone can do the math, I've been killing Sir32 virus all day [;)].

55gr M193 from 1/12 and 1/7 twist barrels produces the same wound profile.

I personally prefer the Vortex supressor to all others. Nice thing about 16" bbls is you're not locked into any particular one. Beware that there are still some bad Vortex out there. Long time member and contributor Dave G. reports in another thread of a bad one. Shoot one on your 16" or 20" and if it survives have it welded on the 14.5" to make it NFA legal.

14.5" bbl is handier than 16" which is handier than 20". Nice thing about these rifles is you don't really have to make a choice. In a matter of minutes I can assemble a semi version of the M16A1, M16A2, or M4 Carbine and still have a working flattop Dissipator with ELCAN as a spare.

-- Chuck

Posted: 7/26/2001 4:30:46 PM EDT

[#14]

Hey someone chime in here with the answer to this one? What is a "Phantom?" I just bought a rifle equipped with one, it's in transit.

Thanks.

Posted: 7/27/2001 9:22:52 PM EDT

[#15]

Stick the Phantom on it!
I have two installed and they out preform anything that I have seen so far.

A phantom is a flash hider.

[ARCHIVED THREAD] - Attn. Senior Members who know their stuff???

General » General Discussion

Warning

Confirm Action

About AR15.COM

Stay Connected

Newsletter

Contact Us