View Full Version : BCM lw BFH barrel vs. Standard govt. profile barrel(all things considered)
Planning a 14.5 build and have some technical questions.
I've read over a over that if you want to shoot at higher rates of speed then go with standard/govt profile barrel because it doesn't get hot as fast. But the logic here seems flawed in that yes it will take longer to get hot but will also take much longer to dissipate the heat once it is hot. Am I right?
Second, people say (mostly assume) that once the lightweight barrel IS hot, it is less accurate than a govt. profile barrel is.... I could see this being true IF a government profile barrel were the same .750ish diameter the the entire length of the barrel instead of basically being a "lightweight profile" from the gasblock to the receiver leaving the heavy end ass backwards to cause more barrel sag at higher temps than a lightweight barrel would... Or is it my logic that is backward?
While we are talking about heat, and "getting hot faster" on a lightweight barrel, since most people's support hand placement is behind the gasblock anyway does heat really matter from a comfort standpoint since that section of either barrel would be equally hot under a rail?
And finally IF the govt profile barrel does in fact hold accuracy better at higher temps from rapid strings of fire. Would getting a BFH lw barrel correct that problem by adding stiffness and in the end being better all around than a standard govt profile barrel?
I did do a search btw coming up with only the following thread which did not answer any of these specific questions
https://www.m4carbine.net/showthread.php?t=80444&highlight=Lw+barrel
I suggest the following;
Look at the barrel of a SCAR, AK47, M16A1 and probably the FN FAL.
1slow01Z71
11-01-13, 23:03
Ive got a 14.5 LW DD mid barrel and have dumped a couple mags pretty quick through it. With the NSR it does get a little warm but I didn't see a big loss in accuracy with a RDS. With a scope I might be able to but I still had no problem hitting center of mass quickly at 100yds. The LW is worth it to me for the lighter gun and quicker swing. Its pleasant to lug around the deer lease during the summer for hogs.
TacticalMark
11-01-13, 23:33
SOCOM profile
Would it make any sense if you made the last half of a lightweight barrel a little thicker?
No?
It would if you needed to mount an M203.
The profile has nothing to do with heat or accuracy.
Planning a 14.5 build and have some technical questions.
I've read over a over that if you want to shoot at higher rates of speed then go with standard/govt profile barrel because it doesn't get hot as fast. But the logic here seems flawed in that yes it will take longer to get hot but will also take much longer to dissipate the heat once it is hot. Am I right?
Man, I wish folks would look up the laws of thermo dynamics. If your're talking temperature, lets say you heat up a barrel 16" long and 2" in diameter and a barrel of the same length but only 1 inch in diameter to 250*, the 2 inch barrel will contain more heat and will take longer to cool off to ambient temperature. However, if you heat both barrels with the same amount of heat, say 250 BTUs (British Thermal Units), the 2" barrel will be cooler than the 1" barrel because it has more material and will cool off to ambient temperature quicker because it has more surface to radiate heat
Second, people say (mostly assume) that once the lightweight barrel IS hot, it is less accurate than a govt. profile barrel is
In general, it should make little difference because both barrels are roughly the same diameter where it matters when it comes to heat- close to the chamber. However, every barrel is a law unto itself and barrel quality is a factor as to how a barrel reacts to heat
Would it make any sense if you made the last half of a lightweight barrel a little thicker?
No?
It would if you needed to mount an M203.
The profile has nothing to do with heat or accuracy.
Lightweight barrels can take an M203 just fine.
PatrioticDisorder
11-02-13, 07:40
Get the lightweight barrel and stop over thinking it!
Why did I go with a BCM BFH? Because the LW was already pricey and the BFH was 'only' $70 more and there were some (not a lot) comments concerning the shift in POI of their LW barrel.
http://www.danpassaro.com/img/s10/v109/p1763330354-10.jpg (http://www.danpassaro.com/img/s10/v109/p1763330354-6.jpg)
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While I have not shot the BCM BFH LW for accuracy (just shot a few rounds out of a buddies gun) I do have the BCM BFH GOV barrel and have shot it for "accuracy". I was shooting my GOV barrel with a 3-9x scope at 500yds on 11" steel. From the start to the end of the 2 mags or so, the poi shifted a lot.
I started with about a 3-4 mil vert hold off. By the end I was down to between a 1.5-2 mil hold off with a reduce percentage of hits.
There were other factors such as wind gusts so not all of the reduction in accuracy came from the barrel heating up.
Now I have switched out to an aimpoint so Im not looking for that accuracy.
Get the lightweight barrel and stop over thinking it!
Kind of what I'm thinking
shoot at higher rates of speed
What does this even mean? Bullet acceleration?
What does this even mean? Bullet acceleration?
I think he means rate of fire.
Dude don't come in my thread trolling with useless smart assed comments.. Everyone else understood what I meant just fine
I have a 14.5 Standard Government profile and 16 inch BFH LW barrel. Both are great barrels. I prefer the 16 with a geissele mk4 rail. I'm shooting both with Micro H1's and both seem on par as far as accuracy goes.
HighDesert
11-02-13, 16:42
Went through the same choice...
You are overthinking it like others have said and, like IG said, there are plenty of other battle-rifles that have a lw barrel as their standard...
I have owned BCM standard profile, BFH standard and now currently a BFH LW - the only difference in accuracy I notice is from fatigue after an afternoon of shooting...
I would still take LW profile for its balance, over retaining a little bit more accuracy if it came down to it...
You will drive yourself nuts if you overthink this.
Have you researched the difference in the weight of the barrel profiles. There is really not much difference.
Yeah it's 4oz on a 16" should be 3.5-3.75oz on a 14.5
HighDesert
11-02-13, 21:19
Have you researched the difference in the weight of the barrel profiles. There is really not much difference.
Yeah it's 4oz on a 16" should be 3.5-3.75oz on a 14.5
Thats like getting to add a "free" x300U with batteries to the end of the rail.
Its not the difference in weight, but the difference in balance that you feel...
Unless you are throwing a ton of shit close to the end of rail/handguard, it is very noticeable when you pick up a standard vs lw middy that are set up the same way.
Heavy Metal
11-02-13, 21:49
Whoever said balance was right. ARs have lightweight aluminum receivers that tend to exaggerate the sensation of any additional weight toward the muzzle.
Still, my belief is that, within reason, lighter is better.
I went with a LW barrel, but not BFH :( it was during the panic and had everything for that rifle ready except the upper, and I chose the first that came in stock at BCM which was the standard.
I prefer it over the Govt Profile, it has everything you need without excess weight.
HighDesert
11-02-13, 22:04
I went with a LW barrel, but not BFH :( it was during the panic and had everything for that rifle ready except the upper, and I chose the first that came in stock at BCM which was the standard.
I prefer it over the Govt Profile, it has everything you need without excess weight.
Honestly, the BFH is a bit of a marketing gimmick especially if you look into the history of hammer forging in that its essentially just a more economical way for more barrels to be produced at a quicker rate... That is why it was developed - no other reason but to save money on mass production.
Accuracy: I'm not an expert but did not notice any significant difference in accuracy between non and BFH BCM barrels, and actually found my non-BFH BCM to have a tiny tiny edge if I was forced to unscientifically compare.
Life: Don't forget BCMs "filthy 14" was not BFH and ate more rounds than 99% of us will shoot in a lifetime.
With that said, I went BFH just because I got a good deal on the used market - I think a lot of people would be better off using the difference in $$$ on mags or ammo.
Sorry to get off topic...
I own both profile barrels in 14.5 and like them both. I haven't experienced any difference in accuracy but prefer the gov profile. This is due to me personally having less barrel bounce running drills. I'd go with the one that suits your shooting style best, both are great.
I own both profile barrels in 14.5 and like them both. I haven't experienced any difference in accuracy but prefer the gov profile. This is due to me personally having less barrel bounce running drills. I'd go with the one that suits your shooting style best, both are great.
This is/was another concern of mine.
I'm already planning on the extremely light km13 once it comes out.
The only things the gun will have up front is front sight inforce light and bcm keymod stubby vert grip.
You could go with the profile in between the two. Centurion, Spikes, Noveske and PSA all make a barrel in this profile. Centurion also makes this barrel in 14.7 carbine length. With the gas block closer to you the swing weight should feel less than a mid-length, and at 14.7 you can use a shorter muzzle device. This barrel is also been reported sub MOA. All the brands listed above are also FN barrels. I don't own a PSA but have seen one In a shop next to a noveske and they appeared exactly the same.
Honestly, the BFH is a bit of a marketing gimmick especially if you look into the history of hammer forging in that its essentially just a more economical way for more barrels to be produced at a quicker rate... That is why it was developed - no other reason but to save money on mass production.
Accuracy: I'm not an expert but did not notice any significant difference in accuracy between non and BFH BCM barrels, and actually found my non-BFH BCM to have a tiny tiny edge if I was forced to unscientifically compare.
Life: Don't forget BCMs "filthy 14" was not BFH and ate more rounds than 99% of us will shoot in a lifetime.
With that said, I went BFH just because I got a good deal on the used market - I think a lot of people would be better off using the difference in $$$ on mags or ammo.
Sorry to get off topic...
Quoted for truth.
Hammer forged barrels are the sales gimmick of the decade.
The_Hammer_Man
11-03-13, 02:37
16" LW profile barrels are just as accurate as their thicker brothers IF you pay attention to a few things.
I've received customer comments that the LW profile barrels feel "whippier" than their standard thickness barrels.
The reason is fairly obvious. Thin walled tubes flex more/faster than thick walled tubes.
In my experience, the means to mitigate the "extra action" is either to use the hammer forging methods used by several barrel vendors or use specialized muzzle devices that can be tuned to an individual barrels characteristics.
An alternate method that I've personally used to make a LW barrel is to use a standard weight barrel and have it fluted down to .650 in the flutes. This will not be as light as a "real" LW barrel but, it will be almost as light with considerably greater rigidity due to the fluting.
The above is my preferred method of solving the LW vs Standard profile issue.
...Thin walled tubes flex more/faster than thick walled tubes...
Actually, it's the stiffer tubes that vibrate at a higher frequency
PatrioticDisorder
11-03-13, 10:24
Quoted for truth.
Hammer forged barrels are the sales gimmick of the decade.
Increased barrel life.
Heavy Metal
11-03-13, 10:50
Increased barrel life.
The Germans figured that out during WWII with the MG-42.
HighDesert
11-03-13, 11:07
Increased barrel life.
Again, I went bfh, but is there actually numbers based evidence of this? I could never find any.
I always assumed the increased barrel life was attributed to the thicker chrome layer FN was putting in the barrels, not the actual barrel steel...?
I also assumed that having a thicker chrome layer would also inherently make a barrel less accurate...?
I admit to having not much, if any, experience with the science of barrels and metals past casual shooting.
steyrman13
11-03-13, 11:17
Again, I went bfh, but is there actually numbers based evidence of this? I could never find any.
I always assumed the increased barrel life was attributed to the thicker chrome layer FN was putting in the barrels, not the actual barrel steel...?
I also assumed that having a thicker chrome layer would also inherently make a barrel less accurate...?
I admit to having not much, if any, experience with the science of barrels and metals past casual shooting.
Not entirely due to thicker chrome. Read up on Steyr, Glock, Sako (TRG) etc barrels. You might find it is actually not just for "cheaper" or "quicker" production. You actually end up with a more quality controlled product with ChF, better steel characteristics, etc.
PatrioticDisorder
11-03-13, 12:17
Again, I went bfh, but is there actually numbers based evidence of this? I could never find any.
I always assumed the increased barrel life was attributed to the thicker chrome layer FN was putting in the barrels, not the actual barrel steel...?
I also assumed that having a thicker chrome layer would also inherently make a barrel less accurate...?
I admit to having not much, if any, experience with the science of barrels and metals past casual shooting.
I think it's pretty well documented, companies like FN with the SCAR went with CHF barrels and that platform has been extensively tested. FN touted a 30k barrel life in the 17s (albeit .308 is lower velocity), most companies that produce CHF claim 20k barrel life in 5.56 vs. button barrel 6-10k barrel life.
Either way I wouldn't lose sleep over it. If I was to pick I'll take CHF, but I would lose any sleep buying say a Colt 6920 where your only choice is to government profile button barrel. When the barrel is shot out and accuracy/velocity degrades, have the barrel replaced.
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