What is the big deal about non HBAR being illegal?

[vinjet700]

The truth is the politicians who forced that through are idiots.

This

 

[Forest]

Correct. 6oz to 8oz of weight is the only significant difference.

1 full pound for 20" barrels.

It's not the amount of the weight though, it's where it's located (out on that lever) so it seems heavier than it really is.

If all you do is bench shoot, or shoot prone, you won't notice the difference at all.

If you like to attend carbine classes, or spend the day shooting offhand, you'll notice the difference. Given the choice I prefer the lighter barrel, but the heavier one won't kill you.

 

[lkenefic]

I believe someone else mentioned also that the lighter contour barrel will dissipate heat a bit faster than the HBAR... of course if the HBAR has a fluted barrel...

 

[RoadDawg]

How come nobody mentioned that the HBAR does not have the cut away where one can mount an M203 launcher? THAT'S why they want it banned. So we can not launch our greenades.

 

[johnnyb2]

Sorry, but a lighter barrel does NOT dissipate heat faster. The attributes of a heavy barrel are: They dissipate heat better, provide better harmonics against distortion, provide less barrel WHIP, are stronger, and if you look on the picture here, the HB is much thicker at the end where it meets the receiver. This is where erosion and distortion are caused by excessive heat, and the thicker steel helps prevent this, and provide longer - more accurate life. This is what I have learned about the difference over the past few years, and experienced. DD just came out with the first HAMMER FORGED STAINLESS STEEL barrel, which should be pretty damn bad ass. I bet it costs a ton though...:-)

In bet more than 50% of people that own a AR put less than a 1000 rounds a year on them. Its all the hype that makes us want to buy the best and baddest out there...not that we need all that stuff....but....some of it sure does look good!! Hahahahahahahah

 

[johnnyb2]

GRENADES

How come nobody mentioned that the HBAR does not have the cut away where one can mount an M203 launcher? THAT'S why they want it banned. So we can not launch our greenades.

Yeah, I am all out of those darn grenades they seem pretty expensive also.....!!!

 

[Boom Boom]

1 full pound for 20" barrels.

It's not the amount of the weight though, it's where it's located (out on that lever) so it seems heavier than it really is.

OP referenced 16" barrels (for new rifles per the original question). At this point for him, it's HBAR or nothing if he doesn't have a pre-10/1 lower.

 

[1ceman]

At this point for him, it's HBAR or nothing if he doesn't have a pre-10/1 lower.

Thats only assuming that I will only be a Maryland resident for the rest of my life. I have been considering jumping across the river to Va. If things in Md continue like this.

 

[pwoolford]

The HBAR is so substantially heavier than a standard pencil profile barrel that only someone of John Rambo's physique could carry one and create a rampage mass shooting. That being the case, politicians decided that being shot by such a person is much better than being pummeled to death.

Or worse yet...him needing to use the dreaded Rambo knife

 

[VikingFan65]

I would like to take my original Bushmaster XM25-E and set it right next to a Windham HBC rifle and ask why one is legal and the other is not???

They were made in the same factory, using the same tools, probably by the same people. The only difference is a few years time and the rights to the name "Bushmaster".

The utter assploding idiocy of it astounds me.

You are thinking too logically. That won't work with politicians.

 

[Hopalong]

Sorry, but a lighter barrel does NOT dissipate heat faster.

Heat dissipation, all other things being equal, is mainly a function of surface area. More surface area = more heat dissipation. HBAR barrels have more surface area so they would actually dissipate heat faster than light barrels.

However HBAR barrels also have more volume, so they can store more heat to dissipate. Assuming the Square Cube Law holds, the relative volume of an HBAR barrel should be greater than it's relative surface area when compared to a light barrel. I haven't done the math to see how long both actually take to get back to ambient temperature when heated, but from my personal limited experience (and a little SWAG-ing), lighter barrels return to ambient temperature faster than heavier ones.

Assuming I'm correct, it would be correct to say that light barrels dissipate their stored heat in a shorter time, not that they dissipate stored heat at a faster rate.




Sorry. I haven't flexed my physics muscles in a while. B^)

 

[cantstop]

This is what I found
Really an 8oz difference????

Colt 6920, 16" M4/governmnet profile barrel with 1:7" twist: 1 pound, 12 ounces.

Colt 6721, 16" HBAR with 1:9" twist: 2 pounds, 3.4 ounces.

I

 

[Boom Boom]

Thats only assuming that I will only be a Maryland resident for the rest of my life. I have been considering jumping across the river to Va. If things in Md continue like this.

Many of us are leaving or buying a second house to establish legal residency elsewhere. You might be following us.

 

[amoebicmagician]

nope

Sorry, but a lighter barrel does NOT dissipate heat faster. The attributes of a heavy barrel are: They dissipate heat better, provide better harmonics against distortion, provide less barrel WHIP, are stronger, and if you look on the picture here, the HB is much thicker at the end where it meets the receiver. This is where erosion and distortion are caused by excessive heat, and the thicker steel helps prevent this, and provide longer - more accurate life. This is what I have learned about the difference over the past few years, and experienced. DD just came out with the first HAMMER FORGED STAINLESS STEEL barrel, which should be pretty damn bad ass. I bet it costs a ton though...:-)

In bet more than 50% of people that own a AR put less than a 1000 rounds a year on them. Its all the hype that makes us want to buy the best and baddest out there...not that we need all that stuff....but....some of it sure does look good!! Hahahahahahahah

There is no way that Daniels Defense has come up with the FIRST hammer forged stainless steel barrel.

I've seen them advertised on AIM surplus for quite some time, as well as the fact that because of the characteristics of stainless steels, hammer forging is the best way to create rifling without creating chromium carbides.

In addition to this, the Mini-14 barrels have been hammer forged for some time, and the vast majority of the ones sold are stainless.

 

[amoebicmagician]

http://www.aimsurplus.com/product.aspx?item=XVAP16SS

These barrels are not the ones I am talking about, but these have improved polygonal rifling. Any polygonal rifling is INCREDIBLY hard to produce by cutting. The only easy way to create a polygonal barrel profile is to hammer a barrel blank around a mandrel.

 

[amoebicmagician]

Also there's this http://palmettostatearmory.com/inde...ged-stainless-steel-heavy-profile-barrel.html

And many others.

 

[Scott7891]

Thats only assuming that I will only be a Maryland resident for the rest of my life. I have been considering jumping across the river to Va. If things in Md continue like this.

You might want to jump a little further than Virginia. I know I am.

From the demographics it looks like Virginia will be just like Maryland in 10 years. I hope I am wrong but I'd rather play it safe than have to deal with Maryland Part II.

 

[Brooklyn]

Heat dissipation, all other things being equal, is mainly a function of surface area. More surface area = more heat dissipation. HBAR barrels have more surface area so they would actually dissipate heat faster than light barrels.

However HBAR barrels also have more volume, so they can store more heat to dissipate. Assuming the Square Cube Law holds, the relative volume of an HBAR barrel should be greater than it's relative surface area when compared to a light barrel. I haven't done the math to see how long both actually take to get back to ambient temperature when heated, but from my personal limited experience (and a little SWAG-ing), lighter barrels return to ambient temperature faster than heavier ones.

Assuming I'm correct, it would be correct to say that light barrels dissipate their stored heat in a shorter time, not that they dissipate stored heat at a faster rate.




Sorry. I haven't flexed my physics muscles in a while. B^)

Do not forget to include the fact that more mass = lower temp = slower heat transfer ... I think that as exponential in the delta T and may explain a lot

but the it the issue is thermal expansion ( wrt accuracy changes ) temperature not heat would be a very key issue.

And of course barrel harmonics would dominate both i think.


Very interesting -- wonder if any one ever did a formal model to see which variable dominates .. at some T the barrel harmonics may change as well.

Now I am thinking none of this matters at 5.56 type ranges... but who knows.. and I bet trigger dominates the all then wind then cartridge variations and the barrel harmonics


If we ever get to get back to just shooting instead of politics this might bea fun experiment ...

 

[MedievalEngineer]

It's too bad the assault clips can only be used once and must be thrown away, though.

It was bizarre, right as my bolt locked back, my magazine disappeared. Why did I buy those biodegradable magazines?

 

[Hopalong]

Do not forget to include the fact that more mass = lower temp = slower heat transfer ... I think that as exponential in the delta T and may explain a lot

but the it the issue is thermal expansion ( wrt accuracy changes ) temperature not heat would be a very key issue.

And of course barrel harmonics would dominate both i think.


Very interesting -- wonder if any one ever did a formal model to see which variable dominates .. at some T the barrel harmonics may change as well.

Good point. Higher temperature = faster heat transfer.

I would seriously hope that the bulk properties of rifle barrels aren't noticeably impacted by the kinds of temperature reached by regular use, but they could be. That's not something I've really looked into.

Now I am thinking none of this matters at 5.56 type ranges... but who knows.. and I bet trigger dominates the all then wind then cartridge variations and the barrel harmonics

There's an old rule I once heard somewhere. 75% of accuracy is the shooter and 75% of what's left is trigger and ammunition. That means optics, barrels, and other gizmos make up about 6% of overall accuracy.

Not sure I agree with the numbers, but I think the principle is spot on. Good skills, a consistent trigger pull, and consistent ammunition will get you most of the way to good accuracy, which is why I'm not buying any massively pimped out guns until I've mastered the basic platform. Given how infrequently I shoot, I don't see this happening any time soon.

If we ever get to get back to just shooting instead of politics this might bea fun experiment ...

I don't get to shoot nearly often enough.