Why is 4150 steel better?

[Bimmer]

Originally Posted by GONIF

let those who want to settle buy 4140, I will continue to buy 4150 CMV.

+1

I'm one of the ones who's willing to settle. Life is full of compromises.

[mmike87]

Originally Posted by C4IGrant

The chart is incorrect currently on the CMMG and BM barrel steel. They are using the cheap 4150 (not the steel that follows the MIL-B-11595E spec).

4150 (cheap version) is better than 4140.

What makes steel following under the MIL-B-11595E spec is that is so rare (read hard to get) and more expensive. This is why only a FEW companies use it.


C4

Thanks for the clarification.

[C4IGrant]

Originally Posted by Bimmer

+1

I'm one of the ones who's willing to settle. Life is full of compromises.

Another thing you might be compromising on is the quality of the chamber. We see a lot of .223 chambers in 4140 barrel. Cheap = cheap.


C4

[C4IGrant]

Originally Posted by mmike87

Thanks for the clarification.

You are welcome.

C4

[furyfighter20]

Originally Posted by rightwingmaniac

check out pof's specs. pretty awesome:

Heavy contour, Fluted to reduce weight and Heat
4150 Mil-B-1159F Vanadium Alloy (machinegun rated)
70 Rockwell case hardened heat treated "5R" polygonal barrels are 2X harder then Mil-Spec & Hammer Forged barrels
Corrosion resistant and 10 times thicker and hardness than mil-spec chromed lining
"5R" Polygonal Rifled barrels

rightwingmaniac thanks man you just answered my question also it pof a good rifle im thinking about buying the p-308 they offer

[rsilvers]

I see no reason why a 'civilian' would want a lower grade of barrel. It is like saying "civilian's don't need alkaline batteries - they only need standard dry cells." Better is better - does not matter who you are.

But if you re-barrel when your accuracy standard threshold is crossed, then it can be looked at in terms of cost per shot in the same way that tires can be cost per mile or batteries can be dollars per hour of use. I believe alkaline batteries are actually cheaper per hour of use. Is that also true of 4140 vs 4150 in cost per shot? I don't know. But any customer should do the math - military or civilian - and make an informed decision.

So a $200 barrel that lasts 6000 rounds is 3.3 cents a shot.
A $350 barrel that lasts 8000 rounds is 4.3 cents a shot.

A user that might not be able to re barrel at any given moment would want the more durable one. This could be either a military person in the field, or a competitive shooter who needs a barrel to last an entire season.

[Mjolnir]

Speaking with John Noveske and Mike Rock you could have "416" that will give you similar life to a chromoly barrel and it would conceivably be more accurate. Some of the alloys that would better serve OUR purpose (i.e., people who train and don't use the weapon in a suppressive role) would be 17-4 PH and 9310. What specifications (e.g., surface hardness, core hardness, etc.) I did not ask as I don't need to pry (it's proprietary).

[rsilvers]

416 is said to have about 15% more life than a non-chrome plated 4140 barrel. I am not sure how it compares to a chrome-plated 4150 barrel.

[kennith13]

Originally Posted by gotm4

I can see how that statement implies that whatever your choice of barrel is (if it's not 4150 CVM ) than it's substandard.

What I think every shooter should do is look at how hard and often they use their own ARs. If it's not anywhere near as hard as a full auto gun or 3gunner, then it's probably just money saved by using steels other than 4150 CVM.

I suppose it technically would be substandard, since there is indeed a standard for the platform, at least as far as Uncle Sam is concerned. I know that's not what you meant, but I couldn't resist the joke.

On to my thoughts.

Do my firearms need it? Maybe, maybe not. That doesn't mean I don't want the best barrel steel I can get, and that doesn't mean I always end up with the best.

There are a number of military carbines that could have made it with lesser steel during much of their use. Every now and again, however, it matters. Perhaps there is an inconsistency in the manufacture, perhaps some rapid heat cycling. Perhaps even an unexpected and prolonged direction of suppressive fire. Sometimes, for them, it matters, and good enough doesn't help when that happens.

Many long-running civilian firearms, and even some military firearms, are built with materials that just aren't as good as what we look for in ARs.

I shoot for fun, and even manage to enjoy it at times, but a some of the items in the toy box aren't toys all the time. Thankfully, rarely are they asked to do more than resist corrosion and stay assembled, even when they are being carried. That said, they aren't any more than dead weight if they can't perform under the worst conditions I can plan for, so, at least for these few non-toys, I try my best to buy the best.

Will it ever make a difference? Probably not. In the end, there are far more immediate issues to deal with when barrels begin to heat up. Issues like, simply as an example, bullets. Specifically, those bullets that caused the heating of barrels not attached to firearms that you yourself are holding.

For someone who enjoys frequent courses of instruction, large volume shooting, and who tops off his ammunition supply as frequently as he does his fuel tank, I don't think there is much of an option, really. It's only sensible to use the best barrel you can buy. If your ammunition in a month costs more than the barrel, it is likewise sensible to spend more on a barrel.

If, however, the denizens of that evil lord with whom you wage constant war are no more than pop cans and occasional bits of offensively arranged geometry, there is no real need to look beyond financial logic and safety when choosing such materials. That doesn't mean you shouldn't buy the better barrel, it just means that going with a cheaper barrel will leave you at worst with an unholy pop can.

The way I figure it, you know if you need that milspec steel. The question is, do you want it? If you do want it, the little question of need shouldn't stop you from spending your money on what you want. I've got lots of crap I don't need, and I enjoy all of it.

[Robb Jensen]

Originally Posted by kennith13

I suppose it technically would be substandard, since there is indeed a standard for the platform, at least as far as Uncle Sam is concerned. I know that's not what you meant, but I couldn't resist the joke.

On to my thoughts.

Do my firearms need it? Maybe, maybe not. That doesn't mean I don't want the best barrel steel I can get, and that doesn't mean I always end up with the best.

There are a number of military carbines that could have made it with lesser steel during much of their use. Every now and again, however, it matters. Perhaps there is an inconsistency in the manufacture, perhaps some rapid heat cycling. Perhaps even an unexpected and prolonged direction of suppressive fire. Sometimes, for them, it matters, and good enough doesn't help when that happens.

Many long-running civilian firearms, and even some military firearms, are built with materials that just aren't as good as what we look for in ARs.

I shoot for fun, and even manage to enjoy it at times, but a some of the items in the toy box aren't toys all the time. Thankfully, rarely are they asked to do more than resist corrosion and stay assembled, even when they are being carried. That said, they aren't any more than dead weight if they can't perform under the worst conditions I can plan for, so, at least for these few non-toys, I try my best to buy the best.

Will it ever make a difference? Probably not. In the end, there are far more immediate issues to deal with when barrels begin to heat up. Issues like, simply as an example, bullets. Specifically, those bullets that caused the heating of barrels not attached to firearms that you yourself are holding.

For someone who enjoys frequent courses of instruction, large volume shooting, and who tops off his ammunition supply as frequently as he does his fuel tank, I don't think there is much of an option, really. It's only sensible to use the best barrel you can buy. If your ammunition in a month costs more than the barrel, it is likewise sensible to spend more on a barrel.

If, however, the denizens of that evil lord with whom you wage constant war are no more than pop cans and occasional bits of offensively arranged geometry, there is no real need to look beyond financial logic and safety when choosing such materials. That doesn't mean you shouldn't buy the better barrel, it just means that going with a cheaper barrel will leave you at worst with an unholy pop can.

The way I figure it, you know if you need that milspec steel. The question is, do you want it? If you do want it, the little question of need shouldn't stop you from spending your money on what you want. I've got lots of crap I don't need, and I enjoy all of it.

I agree with you for the most part. You essentially quoted me out of context. I was responding to someone who said we were fear mongering.
I agree if you're shooting more moneys worth in ammo per month than your barrel costs then you should probably buy the best available. But on the other hand many people don't shoot a barrels cost equivalent in ammo in several years and these people can get by with less. If using a lesser quality barrel even chrome lined ones I would recommend having the chambers reamed to true 5.56mm NATO at the neck and throat using a Ned Christiansen reamer.

FWIW IIRC the M1 Garand had a 4140 barrel.

[Mjolnir]

Originally Posted by kennith13

"... I shoot for fun, and even manage to enjoy it at times, but a some of the items in the toy box aren't toys all the time. Thankfully, rarely are they asked to do more than resist corrosion and stay assembled, even when they are being carried. That said, they aren't any more than dead weight if they can't perform under the worst conditions I can plan for, so, at least for these few non-toys, I try my best to buy the best.

If, however, the denizens of that evil lord with whom you wage constant war are no more than pop cans and occasional bits of offensively arranged geometry, there is no real need to look beyond financial logic and safety when choosing such materials. That doesn't mean you shouldn't buy the better barrel, it just means that going with a cheaper barrel will leave you at worst with an unholy pop can.

The question is, do you want it? If you do want it, the little question of need shouldn't stop you from spending your money on what you want. I've got lots of crap I don't need, and I enjoy all of it."

CLASSIC!

[rsilvers]

Originally Posted by mmike87

"The Chart" lists CMMG barrels as "Milspec". Does this mean these barrels are 4150 CMV? It was my understanding they were 4150, but not CMV?

I assume that 4150 NON-CMV is still "better" than 4140? Or do I have this all wrong???

There are non-CMV 4150s which are mil-spec, but they need to match the specific chemical properties outlined in the document.

[rsilvers]

Originally Posted by rob_s

Interesting to note that, despite the fact that 4140 is agreed by all to be the weaker steel when rapidly heated under sustained firing, there does not appear to be a single maker that sells a 4140 barrel that also MPIs and HPTs every single sample of their barrels.

This is because 4150 is more susceptible to cracking than 4140 during heat-treat and so 4150 is more likely to fail and therefore warrants more testing. The other reason is that companies that use the mil standard 11595 steels are trying to meet a mil-spec, and so they are more likely to also do the testing that is specified.

It should be noted that HK and Swiss Arms (Sig 550 series) - which I assume we all agree are very durable barrels, do not meet 11595 mil-spec for barrel steels. In other words - there are other ways to make an ultra-premium barrel than to follow the current US govt. minimum standards and Bushmaster and Remington are doing so with the ACR.

The main difference between 4140 and 4150 is that 4150 has more carbon so that it can be heat treated to a higher hardness/strength. However, no one heat-treats barrels to MAX hardness because they would get too brittle. 4140 can be heat-treated to a hardness/strength greater than what is ever done with 4150 or 4150 CMV barrels. At any given Rockwell value, 4150 tends to have more tensile strength but less yield strength and toughness/impact resistance than 4140. Which is more important to a barrel? Well, it depends on your criteria. If you want the barrel to pass a 'stuck bullet' test and not rupture if a second bullet is fired, then 4140 may do better. And then combine this this added toughness of 4140 with the right lining, be it cobalt alloy, what Swiss Arms does, what the ACR does, etc - and it could easily outlast a 4150 CMV Colt barrel.