Barrel length AR questions

[Neckshot5seven]

I am looking at Del-Ton rifle kits for my next project. I am up in a wad about length and the current debate that the M4 is too short to reach the velocity that .223 is effective at. Are they talking about the 14.5 inch ones??? will a 16 inch model be effective with expanding ammo? or are they talking about military M855 and XM193? I want to be able to drop something if I need to. Should I go for the 20 inch or the 16? is there that big of a difference? your input guys please

 

[Soldiersurfs]

What kind of range do you want out of the rifle?

 

[SimpleIsGood229]

A 16'' barrel will have no trouble with expanding ammo. None a'tol. All this stuff one hears about M-4's not getting sufficient velocity for terminal performance is all due to FMJ ammo. FMJ has to fragment to be really effective. When one uses ammo designed to expand, the point is moot.

 

[funfaler]

The 20" barrel will give you fragmentation with mil-spec ball ammo out to about 200-250 yards.

16" barrel to about 100-150 yards

14" barrel ?

I don't know what to tell you about commercial soft-point ammo, perhaps looking at velocity charts and expansion rates from some manufacturers might lead you to some helpful conclusions.

The point really is that beyond about 300 yards, you are making 22 cal holes in things, regardless of what barrel length, more than likely, it will be much closer than that.

My pref is the 16" barrel, as it makes the carbine more usable and lighter.

The idea of getting a 14", with a permanent muzzle device to make it 16", makes little sense to me, might just as well have that extra 2" of barrel.

The good news, this is not a life long decision, you get one, try it, if you don't like it, you can sell if for near what you have into it, and then buy the other.

That only real benefit I see of the 20" over the 16", is that the sight radius is 4" longer, making for easier long shots. But this is of little consequence, if you are not making long shots, 300+ yards.

 

[rob_s]

To really know if a round will perform as designed from a given barrel length, you really need to know the performance threshold of the ammo in order to figure it out.

If I throw a round at you, it won't deform/fragment, right? Similarly if I fire a round TOO fast (and from too fast of a twist) it could come apart in flight. So then, what you want is something in-between.

Even soft-point and other ammo is the same way. It has a minimum velocity at which it will perform as designed. You need to contact the manufacturer and get this information, then get muzzle velocity data from them to include barrel length so you can run the numbers through a ballistic calculator.

All of this is really moot, however, if you're just looking to punch paper. The paper doesn't care if the round fragments/deforms as designed or not.

 

[sgtcauthon]

all i know is i am issued a standard M4 carbine by the United States Marine Corps, I know many Marines who prefer them to the M16A4's while shooting for marksmanship on the rifle range. Some say they are better. I dont think you will have a problem with the 16''. I don't, and I hunt the worlds most dangerous prey. Terrorists.

 

[Hoppy590]

http://www.ar15barrels.com/prod/gas-systems.shtml

shows both the projectile velocity in terms of inches traveled ( assuming in the barrel) and the gas system pressures

 

[Neckshot5seven]

Well the M4 that our boyz carry in the sandbox are 14.5inch. I could see that being a problem. I might spring for the mid length and 16inch for the longer sight radius. The department I am hoping to get hired on lets their officers choose 870 or AR. There are only a few AR's and rank gets pull. They also let you choose to use personal carbine as long as it meets their needs. I haven't seen an AK, but Im sure It could be done. We have a guy with a M1 carbine. Ill get it ordered as soon before I tell my wife... BTW I got a new toy.... Remimber that weekend you spent at ROSS..... = Hall Pass.

 

[Tarvis]

As was said before, you are probably thinking of FMJ ammo, which won't expand ever. The figures they use are for fragmentation on man sized targets, so unless you are shooting at a similar target with similar ammo you aren't going to have similar results. If you are really worried about bullet expansion, you could try some barnes varmint grenades; I think it was VG's that wouldn't even go through a grape in one piece.

 

[Neckshot5seven]

I dont think I could use something like a varmint grenade on department time. Ill stick to Federal 55gr Ballistic tips. That is what the department uses and It shoots good in my Savage 10 as well.

 

[Picard]

Get the 16" light-weight kit. Then you'll have a compact and, more importantly, light rifle. I did just that and I love my AR.

 

[elChupacabra!]

I'd definitely stay away from the 14.5" barrel - you 1) lose a good bit of velocity over 16" and 2) have to permanantly attach a flash hider to keep it legal without SBR papers. For all that trouble, I'd much rather just have a 16" barrel.

With that said, I built my Del-Ton kit as a 20" and later replaced the Chrome-lined barrel with a DPMS Match 20" Stainless HBAR. My rifle is now set up like the USMC SAM-R, just with slightly more... "economical" parts But hey, it'll still shoot 1MOA with Hornady 55gr FMJBT M193 & H335 and about .75MOA with Hornady 68gr OTM and Varget, so I'm happy with that performance

Anyway it depends on what you want to do with it. I like the longer sight radius and Designated Marksman setup - it's very fun to shoot at the range for ACCURACY purposes, since it's super accurate. And, even though it's pretty heavy (getting up there to 9-10 lbs with scope on top), it's still handy enough that I can shoot it pretty quickly at closer targets.

It's up to you as to what you want to do with it. If you're going to be taking it on patrol, you'd probably do much better with a lightweight 16" barrel, as getting it into and out of the car would be a pain with a 39.5" long rifle. On the other hand, if you want to really shoot it - eventually, you may find yourself wanting a more accurate rifle than a 16" lightweight profile barrel can give you.

It's all up to you. Decide what you want to do with it then go from there. Either way, you're making the right choice getting an AR from Del-Ton - they're a great company to do business with and build fantastic guns