Last year there was this post about melonite vs chrome lined barrels -

http://www.ar15.com/forums/t_3_118/693734_Nitride_vs_chrome_lining.html&page=1

tl;dr - Faxon and mrgunsngear talked about doing a meltdown test. I had given up hope on that test happening, but it looks like the logistics just took a little longer than I thought. This is not the full test, just an accuracy baseline before the meltdown -

https://youtu.be/5TJdGTkivHk.

Would love to see some testing on cold hammer forged chrome lined vs button broached chrome lined which is still the mil spec.

Someone has already done that test.

Look up "Rotary Swaging of Precision Barrels" and "Cold Rotary Forging of Small Caliber Gun Barrels".

From "Cold Rotary Forging of Small Caliber Gun Barrels":


Note what is not mentioned as a benefit, namely better accuracy or increased longevity.

BTW, when this report was written in 1974, the cost savings per barrel was $5.38 over 5000 barrels ($90 in 2017 dollars), assuming the machine is payed off, which cost $300,000 ($1.5 million in 2017).  56,000 barrels would have to be made before any true savings would be realized. For small caliber barrels, the cost savings were significant, but to mandate a change to rotary forging would restrict the number of manufacturing sources.  Further, conventional button rifled barrel have no problem meeting, or exceeding requirements, and at a reasonable cost, no change was made to the drawings.

However, for large caliber barrels the cost saving were larger and therefore, added to the barrel requirements.  Rotary forging is exclusively used in the manufacture of tank and artillery gun barrels (albeit in the form of hot forging).

The saddest part of this whole discussion is that $90 in today's money is only worth $5.38 in 1974 dollars.

Yeah, but GFM rotary forging machines still cost and arm and a leg....

It should be noted there are two forms of Cold Hammer Forging (CHF): rotary forging and rotary swaging.  Both use hammers to cold form the outside of the barrel and impart the rifling contour to the inside, and yield similar barrel properties.  However, rotary swaging machines are slightly less expensive, but cannot do the chamber or exterior profile

I may have missed it in the video but I am curious will this test be done with continuous fire like as fast as he can load the mags, and getting the barrel cherry hot.  Or will it be over time, meaning fire 3-4 mag dumps then wait a few minutes in between?  

The method would make a huge difference and I could see different outcomes based upon this.  If it was continuous fire until it got cherry hot then it would likely be whichever one done better with heat right?  And if it was done with time in between the mag dumps so that the barrel could cool down a little then that would give us a better estimation on what to expect from normal use/longevity.  Sadly I think he meant fire them cherry hot with 500-1k rounds continuous on each barrel then compare afterwards if nothing breaks.  While this will still be interesting, I don't think it will help us out as much as a test conducted on true longevity.  Maybe I have it all wrong, but to me it just seems like two completely different tests and the majority of people even including military would never do the first test in real life even in most fire fights.  But the latter test done over time could show us how they hold up over time and what the rest of us 99.99% of people would expect to see when comparing chrome vs QPQ.

All that said, I love my QPQ barrels and the Gunners are my favorite barrels.  I think they are superior to chrome barrels, but not so much so that I wouldn't buy a chrome barrel if it was in a size/profile I wanted.  Where QPQ barrels haven't been on the market that long yet there aren't too many reports out there on how much life you can get out of them but I have heard a few in the 10-20k round count still going strong.  But there aren't enough people out there that have done this to compare them both side by side yet.  But the few that have gotten in the 5-10k range have reported practically no loss in accuracy but that isn't enough to go off from.  With chrome bores it seems like the average barrel is starting to open up quite a bit at the 10k point and most are replaced at the 12-15k point, but the numbers are all over the place and it can only be a guesstimate.  Each person has their own idea of when the accuracy got bad enough to replace it as well.  I don't think the Nitrated barrels will do any worse then chrome in longevity, and could even see an increase in round counts but it isn't something I would truly bet on either way, to me both are great options.  Any way you put it, I am still looking forward to this video to see what the outcome is.  If it is a true longevity test seeing how well they hold their groups after normal firing then this will be one of the best tests I have seen done in awhile and I am surprised someone hasn't done it sooner.

Yes

$5.38 in 1974 is like $26.50 today according to a couple inflation calculators I just ran it through. The ratio given is more like 1918.
RN makes a good point as well so we must take into account time specific costs for such specialized processes (just because you can get a smart phone like mine for $75 today doesn't mean it would go for $15 in 1974).

Why?  Who actually shoots like that? Mag dump after mag dump?   Won't tell us anything that most would find worthwhile.

I know it'll take time but I'd like to see an average shooting schedule test done as well as the cool mag dump test.

Never going to happen. This "test" is more of the same social media click-bait nothingness.

Real testing involves a laboratory, engineers and serious money. None of which are present here...

I don't understand why you guys are so against this experiment/test...

Sure, no one will mag dump until the barrel breaks, but it is still an interesting experiment to watch.
LuckyGunner did a similar barrel/ammo test before, and it is interesting and fairly informative, which tells us the bimetal/steel jacketed bullet will wear out a barrel faster.

The military did barrel destruction test and suggested the introduction of the M4A1 w/ its heavier barrel.
It is very rare for a average soldier to blow up a standard M4 barrel, but the M4A1 still got made.

There are a lot of things we can learn from doing 'strange' things.
If you don't think it is valid, then don't absorb the information and perhaps you can do your own testing.

I, for one, would like to see what happens to these melonite and CL barrel

Again, due to the methodology, you cannot take the LuckyGunner test and conclude bimetal jackets wear out a barrel faster.

There were too many uncontrolled variables, specifically the differences in powder flame temperature and priming compounds, both of which have a more profound effect on barrel wear than jacket composition.

That's why methodology is so critically important.

Nitrided small arms barrels have been on the market for a very long time.

To sum it up, we can agree that we disagree that the test have any sort of appreciable value for the firearm community.  

IMO their test still tells you that steel/bimetal bullet will create more wear on the rifling than copper.
Plus, the steel case ammo they tested, Wolf and Tula, which both are significantly slower than Xm193.
Rubbing steel against steel is not the same as rubbing copper against steel.

I've  done a lot of mag dump shooting in the past with my SR15 Mod1, it was close to being shot out after 4k of steel case and 8,500rds of brass case. (I had a thread about it)
Currently, my 2nd SR15 Mod1 have 13,600rds through it, all brass case copper jacketed(mostly 5.56 spec), with similar shooting schedule and mag dump, and it shows no noticeable degradation to the rifling.
I went shooting yesterday to check accuracy, the best group of 10rd at 100yard benched w/ a sled, was 0.9", but the gun typically shoots 1.25MOA

My old, almost shot out, SR15 Mod1 (I sold it to another KAC owner on the board)


My new/current main shooter, SR15 Mod1's groups from yesterday.
Currently have ~13,600rds through it, all copper jacket ammo.

Like this test done by Colt in their lab which is nothing like what I'll do :

No, it does not tell you this.

It tells you that the bullet, propellant combination used by Tula and Wolf erodes barrels faster than the XM193 control ammunition.  No more.

I have posted elsewhere an Army test of bi-metal vs copper jacketed bullets using the same lot of propellant, same lot of cases, that shows there is no appreciable difference in barrel life, when shot under the same conditions.  The US has been using steel jacketed bullets in 7.62mm for decades, the only reason they never used it in 5.56mm was because the steel jackets bullet are actually structurally weaker, due to the low strength steel alloys used, the thinner jacket walls, and softer core material.  This was especially the problem with the longer M196 Tracer.

The major difference between bi-metal and copper jacketed bullets is how the bore wears.  Given the same propellant, case, and barrel material, copper jacketed bullets experience a velocity loss cause for rejection first, bi-metal jackets experience an increasing of muzzle bore dimensions, leading to keyholing, first.

Lol I don't understand how threads like these end up in butthurt.

Let the man and Faxon test the barrels the way they can afford to, the more data that gets out to us the better. Regardless if the rifle is clamped in a vice and precisely 30 degrees F with all bacterial particulates in the surrounding half mile neutralized and every man around wearing a space suit. Fuckin ARFCOM lol

Apparently you've never been evolved in a real world engineering test.

What is required for a good test:

1) A good understanding of what it is you are attempting to learn and a good understanding of what you are not going to learn.
2) A good good understanding of what variables there are.
3) A reasonable method to control those variables you are not trying to test.
4) Something to compare your results to.

It does not require white lab coated technicians and sterile laboratories.  I have seen, and been involved in many a test that took place in a dirty test cell built in the 1950's . . . .

This test seems to have enough of the above to tell us something.

You are technically correct, the best kind of correct.  Realistically though people will be shooting the commercially available ammo, not reloading using identical powders and primers with the only difference being jacket of the projectile. Thus for shooters that test still held validity if not for the reasons they thought.