Does Anyone know who Chromelines barrels?

19 June 2003, 06:34

<bigcountry>

My good friend has a FN tactical rifle that is chrome lined. We went down to Frederickburg, VA to meet with people who test them. They claim no throat errosion within 15,000 rounds in 308Win. So I have kept close tabs on the throat length of my friends FN SPR A1 rifle. It hasn't changed a bit in 500 rounds. Now my 300RUM, is a different story.

I figured someone would do this procedure for a 22-250 or the new 223 WSSM. Also, to boot, he gets no copper fouling at all. No brushes and no scrubbing. That would be outstanding for the Varmit shooters of the world.

19 June 2003, 15:30

Cold Bore

quote:
Originally posted by bigcountry:
They claim no throat errosion within 15,000 rounds in 308Win...

...It hasn't changed a bit in 500 rounds.

....That would be outstanding for the Varmit shooters of the world.

I'd say that the 15,000 round claim is a BIT exagerrated. [Roll Eyes]

There is a big difference in 500 & 15,000 rounds. I guarantee that if you press on with your test, you'll see erosion.

If there is no erosion in a chrome lined bore, why is part of the annual inspection on an M-16 to gauge bore erosion?

On a different note, serious varmint hunters wouldn't want chrome lined bores, as it's detrimental to accuracy. There is no way to apply it evenly enough to maintain top-notch accuracy, which is what a varmint hunter is looking for.

20 June 2003, 03:42

<bigcountry>

because they get much hotter than a heavy barreled tactical rifle, I would guesss. I am like you though. I would like to see how much at 15K rounds. I am going to keep tabs on it since I load for him anyway. Chrome is some hard ass stuff. I know when working with it at work, I have to grind off a section to drill sometimes. I still think it will be a good idea for 22-250.

25 June 2003, 11:28

scot

"Chrome is some hard ass stuff."

Got nothing to do with it. The bore is eroded by high pressure and temps. It is like a cutting torch. It is not due to friction. Hard steel will not last any longer than the normal kind. Tool steels and chrome have been tried over and over for a hundred years. It never pans out. Intuitively I know it seems that a chrome bore or super hard steel might be the answer. It has been proven time and time again not to be true. A crime lining does prevent corrosion. That is a good thing in a military rifle or machine gun. Here guilt edge accuracy is not as important so they chrome line them.

Good luck and have fun.

25 June 2003, 12:06

<bigcountry>

Ok, let me get this right. Your saying that errosion of chrome at the same temps as say a regular stainless barrel will be the same????????? I don't think so man. Throat erosion is caused by friction. And the heat that is generated by firing round after round will speed up the erosion due to the properties of the metal.

Where do you think the metal is going in your throat? Miracled away by the metal gods? I guess everyone needs to throw away there carbide drill bits and carbide cutters.

25 June 2003, 12:14

<bigcountry>

Quote from FNusa webpage

SPR match-grade barrels are hammer forged from a superior alloy and the bores are chrome-plated for superior accuracy and long life. These barrels meet or exceed Mil-Spec in all criteria.

I am not a metallurgist, but someone better explain to Jim Owens at FN this theory of yours. If you are a metallurgist, then please educate me.

25 June 2003, 13:22

Rock8296

Chrome plating a bore or barrel raises its heat tolerances, making it more resistant to heat, it also make the barrel or bore extremely hard. Military testing with chrome lined M-16's fired 25,000 rounds in quick succesion(allowing some time to cool as not to cook-off a round) and after 25,000 rounds the was to cycling problems, and no major effect to accuraccy or bore condition. There was some erosion as chrome lined barrels are not impervius not to erosion, but it was very little and not detrimental to overall weapon operation and military readyness condition.

Rock

25 June 2003, 15:56

boltman

quote:
Originally posted by bigcountry:

SPR match-grade barrels are hammer forged from a superior alloy and the bores are chrome-plated for superior accuracy and long life. These barrels meet or exceed Mil-Spec in all criteria.

If they were really concerned about superior accuracy then they wouldn't be using hammer forged barrels. The quote above is just more marketing hype. Chrome does extend bore life somewhat but more importantly it cuts down on copper fouling in these weapons that might fire thousands of rounds before it's cleaned. It also is more resistant to damage from heavy handed cleaning practices with steel segmented cleaning rods like is practiced by the U.S. military.

Chrome lined barrels will take more abuse than unlined ones, but at the expense of accuracy. Accuracy that is "good enough" for the military is frequently unacceptable for most dedicated gun nuts.

26 June 2003, 02:14

<bigcountry>

I know what you mean by accuracy. They only guarntee .75MOA. The nerve of them. And I have never seen it yet get .2" groups at 200 yards. usually gets a mediocre 1". Pityful.

And then for a Mcmillian stock, controlled round feeding winchester action, 3lb trigger, and badger scope mount, you got to pay 1300 dollars for a .75MOA out of box gun. Outrageous. I know you guys that have the custom guns built pay alot less than that. Don't ya?

I have a few Krieger barrels and after seeing it shoot, and how easy it is to clean, I would trade them in a heartbeat.

[ 06-25-2003, 17:15: Message edited by: bigcountry ]