AR15 Barrel Profiles

Tragedy

Tragedy

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Hi all, planning on doing my first AR build over the next few months and have a few questions regarding barrels and bolt carrier groups. The Barrel is gonna be 16" mid length gas system .223wylde chamber, preferably chrome lined. BCG is gonna be an m16/FA. Using a Vltor upper and a Spikes lower.

-whats the reasoning for going with one profile over the other? (eg. government, hbar)
-are m4 feed ramps necesary on the barrel? whats an m4 barrel extension?
-also are the different profiles able to have their gas systems upgraded to piston?

So far all ive been able to find manufactured are Stag assemblies.

-been looking at all the bcg's and narrowed it to LMT, BCM, Daniel, Spikes/Fail Zero. Whats the difference between the finishes? parkerized finish, nickle boron finish, chrome finish.
-Being a mid length gas system am I going to have to worry about upgrading the extractor or is that mostly a carbine problem?
 
M4 ramps are nice but not necessary.

US military barrel profiles are retarded, so do not look for "sense" to be your guide in choosing a military barrel profile. Profile affects weight of the firearm more than it typically affects accuracy. Therefore, I always choose the lightest profile available and use it with free-float handguards because I prefer light weaponry over heavy weaponry.
 
My opinion:

HBAR barrels exist for benchrest shooters and manufacturers who don't want to pay for the extra machine time to lighten a bbl to gov't profile.

Unless you have a mtach grade 20" bbl, I would avoid an HBAR personally unless the cost is attractive - I don't seek that out as a "feature", I'd rather have the lighter bbl.

M4 feed ramps are totally irrelevant unless you shoot in full-auto. All you have to remember is that you cannot use a rifle extension in a carbine upper or you may get misfeeds. Carbine upper, M4 extension = OK. Rifle upper and M4 extension = OK. Rifle upper and rifle extension = OK.

Wylde chamber is OK, but an 5.56 chamber is equally OK for most shooters.

Piston or DI does not depend on profile. In general though, buy a bbl with a 0.750" diameter journal for the gas block - that is basically an industry standard size.

BCG finish is about cleaning. Parkerized assemblies are cheapest and work fine. The plated or coated BCG's exist because the yare easier to clean in some circumstances, but in general there is no proven performance gain. FWIW, I run standard parkerized BCGs without difficulty.

IMHO ALL AR15 platforms benefit from the Crane NWC o-ring upgrade. It's a $2 part that is easily added to any bolt, so don't get hung up on that.

Hope that helps.

Tragedy said:
Hi all, planning on doing my first AR build over the next few months and have a few questions regarding barrels and bolt carrier groups. The Barrel is gonna be 16" mid length gas system .223wylde chamber, preferably chrome lined. BCG is gonna be an m16/FA. Using a Vltor upper and a Spikes lower.

-whats the reasoning for going with one profile over the other? (eg. government, hbar)
-are m4 feed ramps necesary on the barrel? whats an m4 barrel extension?
-also are the different profiles able to have their gas systems upgraded to piston?

So far all ive been able to find manufactured are Stag assemblies.

-been looking at all the bcg's and narrowed it to LMT, BCM, Daniel, Spikes/Fail Zero. Whats the difference between the finishes? parkerized finish, nickle boron finish, chrome finish.
-Being a mid length gas system am I going to have to worry about upgrading the extractor or is that mostly a carbine problem?
Click to expand...
 
If you go with a 'custom' or 'match' barrel you can have it turned to any profile you want, so you are certainly not restricted to a limited number of barrel profiles. A 16" length will give nothing up to a 20" or longer barrel in accuracy, with the exception of velocity. A heavier profile will generally take heating up better and retain it's accuracy longer over long strings of fire (this may be important, depending on what you want to achieve with your rifle).
Don't discount chromoly or stainless steel barrels - chrome lining just isn't required for guns not seeing service.
 
My choice of barrel profile is determined by the rifles intended usage. I'm primarily a precision shooter. When I built my first AR for service rifle I built it with a match chamber and uber heavy stainless barrel. It was smokin' accurate off of a bench or bipod (.5-1 moa ammo and shooter dependant) but it was so nose heavy it sucked for standing and sitting position shooting. My second, and current AR, uses a Wylde chamber, medium stainless barrel and shoots .75-1.25 moa with the usual caveats. While less accurate mechanically, I score much better standing and seated for service rifle. For CQB and three gun, I'm now less prone to over swing targets due to the rifles lighter weight and more rearward balance. The down side is that the barrel does heat up much quicker and my groups begin to slowly open up when I'm benching/load testing/screwing around.
 
Claven2 said:
My opinion:

M4 feed ramps are totally irrelevant unless you shoot in full-auto. All you have to remember is that you cannot use a rifle extension in a carbine upper or you may get misfeeds. Carbine upper, M4 extension = OK. Rifle upper and M4 extension = OK. Rifle upper and rifle extension = OK.
Click to expand...

Confused but apreciative .... So Im using a Vltor Mur 1 with M4 feed ramps and looking for a 16" midlength barrel, do i need a barrel with m4 feed ramps or an m4 barrel extension?
 
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