[Grumpy]

Non-chrome/non-treated but appropriate alloy steel I'd say will last *probably* upward of 20,000 rounds before severe accuracy degredation is apparent. Chrome same said steel and add another 15,000 rounds to the life, QPQ nitride and add probably double that.

I say *probably* above because I don't know for sure as I havn't put 20k rounds through my MR556 yet nor do I know anybody who has.

 

[Grumpy]

I can tell you for a fact that the MR556 barrel is not nitrided.

If it had been, my adventures in barrel profiling and cutting it back to 14.5 to pin and weld the flash hider on would have been far, far different. I would have had a post in here about having to buy new bits for the lathe.

Nitriding is a fantastic process and I am very much looking forward to having my barrel QPQ nitrided this month. Insofar as i'm concerned, nitriding will make my barrel superior to a 416 barrel in all aspects once it has been nitrided.

I, for one, am very glad HK did not nitride the MR556 barrels. By not doing so, they made it so that we (people who like to Mod HK import guns) can have the exact barrel profile we want, length we want (16.5 inches and less), and add then nitride.

As far as i'm concerned, this is proof to me that HK actually is paying attention to the US civilian market and while they know that they are hobbled by US import restrictions to release neutered, crappy versions of their good guns, they at least give us the raw materials to make versions that are closer to what we want, whatever that want may be.

To be honest, if HK had factory nitrided the barrels, I wouldn't have bought an MR556 to begin with. I'd have a scar or something else in my stable instead.

For what it's worth, thank you HK for shipping these things to us in the raw like you did. Makes project gunning much, much easier.

 

[Grumpy]

If the nitrined barrel would last for ever, how come the sig barrels are very often replaced after 10000 rounds?, mine 551 did and so did my shooting buddys 550, both barrels was keyholing after that magig 10000 line.
And both was 1/7 twist.

Something tells me your barrels weren't nitrided.

Civ models or mil models?

I"m guessing Civ (SP) models.

Military Sigs are required to be able to perform much better then you describe.

See: http://www.biggerhammer.net/sigamt/550/550techinspection/

And nobody said nitrided barrels will last forever, just significantly longer then untreated barrels and to an extent, longer then even chrome lined barrels and will also have the added benifit of better corrosion resistance then chrome as well.

Having processes such as nitriding is not some magical, unicorn tears treatment, it's simply an investment into the weapon to ensure that it performs to the best of its capabilities for as long as possible.

Fact of the matter is that even at the height of the unpleasantness in the middle east, when our (the US) operational tempo was at its height and our military was literally burning through hundreds of thousands of rounds per training or range session, they still didn't burn up barrels in 10K rounds like you describe.

That being said, if your sig barrels were nitrided and you and your buddy burned them out in 10k rounds, the problem isn't the gun, it's you.