Picking a new M4 barrel...

[onearmedswordsman]

I want to replace the bbl on my M4. I want to be able to shoot more bullets with more accuracy. I can only get 1.25 MOA with 75gr HOR/77gr SMK handloads. Everything else is horrible (4 MOA or worst).

My wish list:
* M4 profile, M4 ramps, 1/8 twist, wylde chamber, polygonal match rifling grooves.
* not decided between ss v chromoly, feel free to chip in.

I have pretty much narrowed it down to either a bbl from Black Hole Weaponry (BHW) or Noveske.

Some questions:
* Can't picture a ss bbl in my M4. BHW offer a matte black finish. What's been your experience with this finish? How close it is to parkerizing?
* Heard some tall tales about Noveske bbls performance. are they true? Is it true Noveske bbls yield 100-200 fps more muzzle velocity?
* Does anyone have any real world accuracy data on both these bbls?

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[onearmedswordsman]

Hi guys, if my questions are too long or complicated, just say whatever you want or think about BHW and Noveske bbls. What the heck! I'll take whatever you dish out.

 

[Taurus 617 CCW]

I build 50 guns per month using the Noveske barrels and I can tell you that they are the highest quality barrel I have ever worked with. You will not be disappointed in them! I put a noveske 14.5" barrel on my personal gun and have not regretted it one bit.

 

[SnackCracker]

I recently bought a Noveske Recce mid length. After months of researching, I haven't heard anything but GREAT things about Noveske. The "hard to please" crowd even love them. I've only shot it with 55gr Remington so far, so I have no input on the accuracy with 70-75 gr. However, I have 100% confidence that it will be more accurate than I am. I still have iron sights only, so my accuracy is limited to my abilities.

Many consider Noveske barrels to be the best.

 

[the4thshake]

I have shot 1/2 moa groups with a run of the mill Rock River bull barrel with the Wylde chamber. Using the same heavy ammo, I shot similar groups with a lightweight White Oak barrel using the same chamber. When the lighter barrel heats up the point of impact shifts slightly. Make sure you get a Wylde chamber what ever you get. My 5.56 chambered guns are lucky to get 1-1 1/2 moa with my best handloads.

 

[Taurus 617 CCW]

Check out this video, it will change your thoughts on what a 5.56 is capable of. He used Federal XM-193 55 gr. ammo out of a 14.5" noveske barrel.

http://www.youtube.com/watch?v=teUnXTs_Rts

 

[onearmedswordsman]

Anyone with direct experience with Black Hole Weaponry barrels? Pricing is very attractive! They appear to meet the same form/fit/function of Noveske bbls at less than half the price! And with more options to choose from!!

 

[Selftest]

The draw to Noveske is an honest one. The barrels seem to be second to none, customer service is amazing, and it's a "name" brand now, in our little world.

Buy once, cry once.

 

[the4thshake]

Doesn't Noveske use Pac-Nor blanks?

 

[Taurus 617 CCW]

Doesn't Noveske use Pac-Nor blanks?

I'm not sure on that one. I do know that they use their own blend of stainless and alloy for the barrel material. They also use their own polygonal rifling in the bore. They are very dense barrels when you compare the weight to a mil-spec barrel of equal length. I do agree that they are expensive but #1 you get what you pay for, #2 they are a local company, #3they have outstanding customer service.

 

[Gunner3456]

Choose your rate of twist carefully. Match it to the ammo you plan to shoot. It's probably not possible to build an AR which will shoot both 55gr and 77gr accurately and consistently.

The longer the bullet, the greater the rate of twist that's needed. Usually that means that heavier bullets need a greater rate of twist, but not always. Even a long but lightweight tracer bullet needs a greater rate of twist and the military found that a 1:7 twist is most accurate for lightweight but long tracers.

The 1:9 twist is a compromise to be able to fire various rounds. The original early 60's Armalites had a 1:14 twist which was soon reduced to 1:12 for 55gr bullets. With the addition of heavier bullets and longer tracers, the 1:9 was chosen. For guns shooting even heavier bullets and tracers, the 1:7 is used.

I'd want to pick one weight (really meaning length) of bullet and stick with it, and choose my barrel for that. Since the 55gr is most available and cheapest, I buy those and prefer a 1:12 twist although the 1:9 is a decent compromise and will also do OK with the 62gr.

IMHO if you're going for long range target, I'd decide on my bullet weight (length) first, and only then buy a barrel.

$.02

 

[the4thshake]

Oh the twist debate...

A 1-8 twist is probably will probably give you the most flexability with bullet weights in an AR. I have personaly shot 45-80 grain bullets through an 8 twist with no issues. Most AR barrels are 1-9 which may or may not like bullets over 70 grains. If you plan on stretching the distance limits with the AR it would be wise to shy away from a 1-9 twist. There is a increasing number of 1-7 twist barrels out there now which do great with the longer bullets up to 80 grains. I shoot 55 grain bullets out of several 1-7 twist ARs all the time. They group just fine and don't vanish into a poof a dust as some on the internet would lead to believe. If you can find a 1-12 twist you best be planning on shooting light <45 grain bullets. The most common weight bullet available for a .223/5.56 is a 55 grain. The 1-9, 1-8 and 1-7 should all do fine with that weight.

 

[bnr32gtr]

Doesn't Noveske use Pac-Nor blanks?

Yes, John does use Pac-Nor blanks but it's what he does to those blanks that makes them special...

I have owned and sold about 12 Black Hole Weaponry barrels and every single one has not shot worse than 1.5 MOA with good ammo like Black Hills. I am and will continue to be impressed, especially when considering the price!

 

[onearmedswordsman]

I had pretty much given up on this thread. Was a bit disappointed at the lack of interest initially. I appreciate the inputs, confirming most of the thoughts I originally had about this issue (w/o going into details).

Now, let's hear it about claims some have higher muzzle velocities clocked out of the Noveske bbls. That is of special interest for me, too. My milspec bbl appears to be too tight. I am loading my 75/77gr handloads at more than 200fps below mk262 velocities because of high pressure signs with both RL15 and Varget (CCI 400 & LC brass). I wanted to try vv N140 and IMR 4895 but you all know what its like these days with powders and primers.

If the claims are true, somehow the rifling, bbl material and the match grade chamber, interact to produce increased velocities, and thus, lower Pmax and I need that or else I'll be stuck with wimpy mk262s clones.

Is Noveske are truly putting out higher mvs, then, there is no reason why BHW bbls aren't, either, at least to some extent. I'd like to hear about that, too.

 

[Gunner3456]

Oh the twist debate...

A 1-8 twist is probably will probably give you the most flexability with bullet weights in an AR. I have personaly shot 45-80 grain bullets through an 8 twist with no issues. Most AR barrels are 1-9 which may or may not like bullets over 70 grains. If you plan on stretching the distance limits with the AR it would be wise to shy away from a 1-9 twist. There is a increasing number of 1-7 twist barrels out there now which do great with the longer bullets up to 80 grains. I shoot 55 grain bullets out of several 1-7 twist ARs all the time. They group just fine and don't vanish into a poof a dust as some on the internet would lead to believe. If you can find a 1-12 twist you best be planning on shooting light <45 grain bullets. The most common weight bullet available for a .223/5.56 is a 55 grain. The 1-9, 1-8 and 1-7 should all do fine with that weight.

Do you use a chronograph? I'm not saying your results are inaccurate - I can speak only for me. For me, a 55gr XM193 spec load at 3150 fps will go all over the place in a 1:7 twist, and will make ragged holes in the target proving that it wasn't spinning straight and true when it hit. I even get some fliers that miss the target at 300 yards.

I have another AR with a 1:9 twist that shoots 1 moa with clean holes with that same ammo. I have another in 1:12 that shoots under 1 moa at 500 yds with clean holes. (all 55gr XM193 spec)

If I shoot 77gr Cor-Bon at 2600 fps in the 1:9 twist, they make clean holes but shoot 3 moa. In the 1:7, they shoot 1 moa still with clean holes.

These are all 20" barrels, fwiw. The problems obviously aren't with the barrels because they are all very accurate with the appropriate ammo. the problems occur when I don't match the bullet length (weight really not having anything to do with it) to the twist rate.

$.02

Look at the difference in length between a 55gr and a 77gr bullet, and think about it. Remember that weight is not the issue but rather length is for twist rate, but the heavier bullet of similar construction will necessarily be longer. I don't believe you can pick just one "best" or even "good" barrel for both of these bullets.

 

[onearmedswordsman]

Gunny, et al,

Thanks for sharing. It is rare to see so much data from someone who is not also trying to sell you something. Not surprisingly, it goes very much in line with my observations, wrt 1/7, 16" 5.56 NATO bbl that came with my M4. The same bbl shooting tracers that occasionally miss the target at 100yd, is also capable of near 1 MOA with the longer/heavier 75gr (.98") & 77gr (1.0") bullets.

Bullet muzzle velocity, bullet length, geometry and mass distribution/density are all variables in affecting in-flight stability. All things equal, we simply choose to ignore the latter three and translate length into weight for there is an almost direct correlation between the two. Experts (of which I'd never claim to be one) agree that best accuracy is attained when rotational velocity (which is directly proportional to muzzle velocity) is the slowest possible to obtain stability.

I am an engineer; it is part of my nature to reduce every life problem into a scientific experiment of some sort. This is one reason why shooting in general is so attractive to me. I have a hypothesis that I hope to be able to prove some day with hard data, that any AR-15 .224 cal chambered rifle with a 16" or larger bbl does not need 1/7 twist rate, and 1/8 should be enough for 75gr - 77gr bullets, magazine length ammunition for best accuracy. Shorter bbls with 1/8 twist rate may have difficulty reaching the initial rotational velocities, and that in top of bullet drop and linear and rotational velocity decay over distance, will make it less accurate at less than 500yd, probably worst than 4 MOA. I have no idea how far, though. In such case (14.5" and shorter bbls), I fully advocate a 1/7 twist. Again, I have very little data to support such claim.

Tracers are a different animal. Mass density and distribution is different to ball and match bullets. I have yet to figure those out. What throws me off is they shoot horribly in my 1/7 bbl. Don't know what to make of it. It just occurred to me I should dissect one to see what they look like inside. First, need to figure how to deactivate them (don't want it to lite up while cutting it in half). Probably should try a hacksaw instead of a Dremmel.

But I digress, I've hijacked my own thread!!

 

[Gunner3456]

Gunny, et al,

Thanks for sharing. It is rare to see so much data from someone who is not also trying to sell you something. Not surprisingly, it goes very much in line with my observations, wrt 1/7, 16" 5.56 NATO bbl that came with my M4. The same bbl shooting tracers that occasionally miss the target at 100yd, is also capable of near 1 MOA with the longer/heavier 75gr (.98") & 77gr (1.0") bullets.

Bullet muzzle velocity, bullet length, geometry and mass distribution/density are all variables in affecting in-flight stability. All things equal, we simply choose to ignore the latter three and translate length into weight for there is an almost direct correlation between the two. Experts (of which I'd never claim to be one) agree that best accuracy is attained when rotational velocity (which is directly proportional to muzzle velocity) is the slowest possible to obtain stability.

I am an engineer; it is part of my nature to reduce every life problem into a scientific experiment of some sort. This is one reason why shooting in general is so attractive to me. I have a hypothesis that I hope to be able to prove some day with hard data, that any AR-15 .224 cal chambered rifle with a 16" or larger bbl does not need 1/7 twist rate, and 1/8 should be enough for 75gr - 77gr bullets, magazine length ammunition for best accuracy. Shorter bbls with 1/8 twist rate may have difficulty reaching the initial rotational velocities, and that in top of bullet drop and linear and rotational velocity decay over distance, will make it less accurate at less than 500yd, probably worst than 4 MOA. I have no idea how far, though. In such case (14.5" and shorter bbls), I fully advocate a 1/7 twist. Again, I have very little data to support such claim.

Tracers are a different animal. Mass density and distribution is different to ball and match bullets. I have yet to figure those out. What throws me off is they shoot horribly in my 1/7 bbl. Don't know what to make of it. It just occurred to me I should dissect one to see what they look like inside. First, need to figure how to deactivate them (don't want it to lite up while cutting it in half). Probably should try a hacksaw instead of a Dremmel.

But I digress, I've hijacked my own thread!!

That's interesting to me because IIRC the military started using the 1:7 twist specifically for the tracer. That's because although light weight, it's also long, similar to a 77gr or so. Other data would suggest that you'd find that it's the aspect ratio of the bullet (in this case considering only the length because the width is always. .224,) rather than weight that determines the rpms needed for stabilization. Longer bullets of any weight in a given caliber should prefer a slower rpm.

You forgot to go into depth about cross-sectional density, aspect ratio of the bullet, ballistic coefficient, rotational differentiation of the two sides of the bullet as relates to atmospheric drag (one side going up as the other side goes down when spinning,) Gyroscopic precession from bullet angling at distance, RPM's as a factor of rifling twist and bullet speed, and...

In my case I followed the lead of the military because they've been doing this for so long. The first AR's were 1:14 in the very early 60's. Then they found that 1:12 was better, always using 55gr. Next they went to 1:9 to add the 62gr to the 55gr, somewhere in there they did the 1:7 for tracers and heavier bullets. I don't know what the 1:8 was for, but obviously longish bullets.

When you really think about it, twist is only a recipe for rpm at a given velocity, and it's rpm which essentially stabilizes the bullet. I don't know, scientifically, why a higher aspect ratio bullet prefers a lower rpm and vice versa.

WHEN I chrony my loads to verify muzzle velocity and therefore rpm, I find that the above theories work and I'm not smart enough to beat the engineers who design and manufacture ammo and barrels.

Ain't it fun?

 

[onearmedswordsman]

You forgot to go into depth about cross-sectional density, aspect ratio of the bullet, ballistic coefficient, rotational differentiation of the two sides of the bullet as relates to atmospheric drag (one side going up as the other side goes down when spinning,) Gyroscopic precession from bullet angling at distance, RPM's as a factor of rifling twist and bullet speed, and...

Just like in your first post, I am guilty of over simplifying the equation. But you cheated, you had to look (didn't you?), whereas I fired from what I could recall from the top of my head.

As you say, we can dispense with most of this math and just adopt what other people have empirically proved to work. It does not hurt, every once in a while, to question what we have for long accepted as true, especially when it is not working as well as it should. Still drive me nuts them tracers flying all over the place.

I want to buy a 1/8 bbl.... probably. If a compelling reason comes across in the form of superbly preforming Noveske, then, 1/7, then, yes, I'd go for it. But I want to do it with my eyes wide open, not like when I bought the M4.

As a matter of fact, what I am getting from this discussion is maybe I should get two barrels, one for the current upper and another one a for a new upper. I've been toying with the idea of building a mk12 Mod 0 upper clone. The Noveske 18" (or maybe a Krieger) looks like the a great candidate. But that will be after I pay some medical bills and and Uncle Sam Big Collecting Arm (aka IRS).

Thanks for contributing your very useful $0.022 (adjusted for inflation) to my thread.

 

[the4thshake]

I have tons of chronograph data and test targets for 68-77 grain loads in various ARs. If someone wants to start a thread in the reloading section I would be happy to share.

 

[Gunner3456]

Just like in your first post, I am guilty of over simplifying the equation. But you cheated, you had to look (didn't you?), whereas I fired from what I could recall from the top of my head.

Actually I took all of that from the top of my head, LOL. I've had enough interest in this as both a shooter and a reloader over time to have already "tried" to study it in depth. I've also, btw, experimented to see if I could find a way to beat the "one barrel doesn't fit all" belief of the gun and ammo makers and the military and I couldn't. No, I didn't look anything up.

As you say, we can dispense with most of this math and just adopt what other people have empirically proved to work. It does not hurt, every once in a while, to question what we have for long accepted as true, especially when it is not working as well as it should. Still drive me nuts them tracers flying all over the place.

I want to buy a 1/8 bbl.... probably. If a compelling reason comes across in the form of superbly preforming Noveske, then, 1/7, then, yes, I'd go for it. But I want to do it with my eyes wide open, not like when I bought the M4.

As a matter of fact, what I am getting from this discussion is maybe I should get two barrels, one for the current upper and another one a for a new upper. I've been toying with the idea of building a mk12 Mod 0 upper clone. The Noveske 18" (or maybe a Krieger) looks like the a great candidate. But that will be after I pay some medical bills and and Uncle Sam Big Collecting Arm (aka IRS).

Thanks for contributing your very useful $0.022 (adjusted for inflation) to my thread.

Welcome. I can't speak about the tracers. Your experience differs from mine and from "conventional wisdom."

If I could have just one AR it would have a 1:9 twist and it isn't any surprise that it's the most common now in off the shelf guns. The .224 bullet in 5.56 is known to have some unique tumbling and breaking characteristics upon impact which causes wound channels beyond what common wisdom would expect. Those events don't happen without speed and they happen more or better with the shorter bullets as in 55 and 62gr, which is what the military happens to use.

Since 55gr is what's most readily available and cheapest as surplus or even as projectiles, that's where most of my attention (and stockpiling) is concentrated. Also, I like to sight my rifles for one load only, and leave them there. I also like to stockpile just one type of ammo for economy and for use in all appropriate guns.

I tune a load for my best and favorite rifle, and then just use that load in the other guns. It works in that way as well as factory ammo because I'm careful that the OAL of the cartridge isn't outside of specs.

My best and favorite load out to 500 yds is a 55gr boat tail at 3150 fps, or about XM193.

$.02