Posted: 1/8/2008 6:07:49 PM EDT
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I am a newbie to this AR thing. I am seriously looking at the Entry Tactical, and I intend to use it primarily for personal defense (PD) and for a good time at the range. If I understand all that I have read, in order to accurately put a heavier round through it (i.e. 75g Hornady TAP or 77 SMK OTM) for PD I will need a 1:7 twist. Is that correct so far? If so, I see that the Entry Tactical has an option for a chrome lined, lightweight barrel. Is there a downside to the lightweight barrel in terms of performance, and can I get at least a chrome moly 1:7 instead of the chrome lined? I know I will need to pay for it. Thanks. |
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Welcome to the world of AR-style rifles. The faster twist rate (1:7 being faster than 1:9) will stabilize a longer (generally heavier) bullet. Conversely, it can overspin shorter (generally lighter) bullets. Projectile profile (it's lenght and shape, and where the weight/mass is located inthe projectile) and velocity will also be important. In terms of accuracy, a 1:7 will generally shoot better at a given distance with a longer, heavier bullet than a shorter, lighter bullet at the same distance. A chrome-lined barrel IS a chrome-moly barrel. The chrome-moly is the steel used in the barrel, while the chrome-lining is a process applied to a chrome-moly barrel for easier loading and extraction, less fouling, and easier cleaning. The downside is that a chrome-lined barrel CAN be less accurate than a non-lined barrel. The plus of a lighter weight barrel is the weight savings that make it a little easier to get on target and less tiring/fatiguing to carry for a long duration. The down side is that it is less capable of shedding heat in extended firing (heat is your barrel's enemy) and that it is less rigid, which can contribute to some associated accuracy issues. Hope that helps. Steve/RRA |
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Steve, Thanks for the quick reply and clarification. I guess my follow up question then becomes: is an Entry Tactical with the chrome lined, lightweight, barrel still generally, for the average shooter, a 1-1.5 MOA rifle? Is accuracy effected more than that? Again, thanks for monitoring this site. |
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Lightweight is a bit of a misnomer there--it's a M4 barrel with 1.5" added to the muzzle (as opposed to a M4A1 barrel with 1.5" added to the muzzle). That's not a1/standard/lightweight profile nomenclature as used elsewhere. This is a lightweight barrel:  If you were interested in increasing barrel rigidity, adding barrel diameter at or ahead of the FSB is foolish. Look at the Noverske N4 barrel for a more intelligent profile compared to the M4 profile, at the same weight. |