I’ve been contemplating my next build and decided on a 14.5" DD or BCM LW Middy with a permed Battlecomp.
Has anyone documented any accuracy loss in the LW barrels, CHF or CMV during long strings of fire?
Personally I cannot tell any difference
I’ve asked this question before. From what I understand, barrel heats up and the point of impact changes, but not a whole lot. I have no first hand experience, just what I’ve been told. I dont know the accuracy differnce at a distance over 100 yards but I hope this helps.
I think in concept that is whats suppose to happen. But I cannot tell the difference. Maybe if you were doing mag dumps in full auto, then trying to make a precise shot? I don’t know, I wouldn’t be concerned with it though.
Point of impact change as opposed to what?
As opposed to group size increasing.
The disadvantage of a pencil barrel is that once you get one, you will feel all your other AR15s are too heavy and want to change them over too. And now I feel that an M1A is a complete pig.
It would seem to me that high volume firing and high level of accuracy are somewhat mutually exclusive. I’m not going to deploy the same gun for the two different roles.
I would never use a pencil barrel for anything.
Why not?
I really like the LW concept. I have no plans on ever affixing a bayonet, so if POI doesn’t change when the barrel heats up like on the old LWs, I can’t see any downsides left. But I’ve been wrong before.
I use lightweight barrels for almost everything 
It would be interesting to have someone run a controlled test. Shoot a 5 round group for accuracy slow fire, fire a 30 round mag and then shoot another 5 round group, with a couple different barrel profiles. Then compare the before and after on each one.
Do they make a ransom rest for AR’s?
I’ve 2 true pencils, 1 govt. profile, and a SS mid weight that I shoot regularly and other than precision type shooting I can’t tell much of a difference. I’ve run the 2 pencils in the last 2 classes I took. One was maxed at 50 tards, the other 200 yards. I never felt I was at a disadvantage accuracy wise, if anything the lack of a pound or so of weight over several days made me feel kind of spry:laugh:.
I also averaged about 400 rounds a day so what would someones definition of high volume shooting be?
Lots of guys say they don’t see much of a difference, but my inner scientist would love to see what the real difference is.
Then I hope you are using full heavy barrels because Government Profile is a joke as far as heat dissapation. It is worse than a lightweight because you are putting weight on the muzzle end that will encourage the barrel to sag more under gravity as the barrel heats.
It is heavy on the wrong end to work. The chamber end is where the bulk of the heating occurs and where you want to sink away most of the heat.
Good to know :sarcastic:
Back on topic, I have no problem with lightweight barrels. Any barrel will shoot larger groups as it gets hot. A lightweight barrel simply has less surface area and less heat sink volume, so it gets hot faster.
Don’t shoot your barrel red hot, and it’ll be fine.
400 rounds a day might or might not be considered a lot. I think what’s more important is how many rounds per minute you were going through, and for how long. One mag dump will get a gun hot, but not HOT hot. Dump 4 or 5 magazines back to back, and you’re really pushing it.
I’d still like to see a quantifiable comparison done that would us tell us exactly what that translates to at 100 yards, and the difference between the barrel profiles.
Backwards, like most things the government does. :(:(
Wasn’t the govt profile done to beef up the bbl for strength at the end for the bayonet?
Kartoffel, Different types of classes are geared towards different goals. My point was that for that class 50 yards was as far as we shot. FWIW the class in question was one of Pat Rogers very highly esteemed Carbine Operator Class. When you combined the accuracy with the speed requirements and target size it is one of the more difficult classes I’ve taken.
I understand and agree with your thoughts on 4-5 mag dumps. I really don’t understand why anyone other than a service member shooting Uncle Sugars peashooters would ever need or want to do this? What’s the point? As a civilian or LEO it’s not relevant to anything.
I have lugged 17+ lb. precision rifles around for many years before building my current 11+lb. rifle. This is a Remington bolt gun but is still relevant to this conversation if we’re talking extreme accuracy. My current rifle has a 20" Rock 5R Remington Varmint contour and will shoot with my old 26" much heavier profile Walther Lothar out to 800. I believe the comparison is similar to a Govt. profile vs. pencil. If you carry one all day or attend classes that have long hours a 6.0-6.5lb carbine will make a difference over a 7.0-7.5lb carbine.
Didn’t Molon do a test of a Colt LW either here or at TOS?
I searched for a thread like that from Molon, but all I found before posting this thread was where he tested a Colt LW with an unmentioned brand of ammo with an ES of 1.32".
That’s great if it’s bulk M193 or M885, not so great if those were a tailored handload. Also doesn’t really answer the question if the barrel was cool to begin the test.