John A. wrote:A-Game wrote:golfindia wrote:A chrome lined barrel will increase in accuracy overtime.
Chrome lined barrels are not known for their "accuracy", and other than smoothing it out in the first hundred or so shots during break-in if there are any imperfections or excess buildup in spots, will also degrade in whatever accuracy they have faster than a non-chrome lined barrel will because it's well known that even in as little as 5000 shots, have already began cracking and flaking.
Chrome lining was added for nothing more than corrosion resistance, not to increase accuracy.
There is a reason why the M24 and many other professional sniper platforms are NOT chrome lined, and I cannot think of any target competitor who uses a chrome lined barrel in competition. The vast majority of them are going to be stainless.
John,
I want to clear up a few things...the internet and rumors really make the waters murky.
There is a reason that every 5.56 military barrel is chrome lined.
This is an AR-15 SPR subject not a F-Class rifle. Both the FN SPR and Sako TRG bolt action rifles use chrome lined barrels and they are widely known to be 1/2 MOA bolt guns. Barrels rated to 15,000 rounds instead of the usual 5,000-8,000 from non-chrome lined barrels. So the notorious accuracy loss is not noticeable in the semi automatic AR weapon system. Chrome lining a barrel does remove the sharp edge in the rifling.
I have never read a study that showed the threshold is 100 rounds for increased accuracy...you got me there. A poor quality barrel usually has poor quality chrome where as a quality barrel has better quality chrome.
The military started to use chrome lining is to extend the life of the barrel. Throat erosion is the main cause of accuracy degradation in barrels due to incredible heat and 50,000psi of pressure on the leade every time the trigger is pulled. Chrome is more heat and pressure resistant than steel. Chrome is excellent for corrosion résistance but can still rust due to neglect. Chrome lining makes for exceptional cleaning in a barrel compared to non lined bores and chambers.
Yes, poor quality barrels can see an accuracy drop after 5,000 rounds of sustained fire. Hi-power shooters will change a barrel out every 10,000 rounds or so but they are pretty obsessed with throat erosion. NOW, speaking in this situation...I would be surprised to see a quality chrome lined quality barrel shot out in less than 20,000 rounds. If you have the money to shoot 20,000 rounds in a few years then you have a few hundred bucks to drop on a new barrel when accuracy drops off, make your money back and you are back in business.
I have seen a few SCARs that have had some slight flaking of chrome...they still shoot as accurate as a Remington 700 hat doesn't have a blue printed bolt, trued action ect.
The M24 was a 6,000.00 weapon. It was a .308 not a 5.56, the 5.56 SPR was not a 6,000 weapon system so I really don't see how that applies here.
I have one rifle with a nitride 4150 barrel and another with a 11595E Certified chrome lined barrel. I cannot notice a difference in accuracy on paper. The other items I listed have a greater impact on accuracy than chrome vs non chrome. I used to be of the opinion that nitride was the bees knees and what to have in a non stainless barrel. The last year working in the industry has changed my opinion due to research, and experience shooting hundreds of barrels, measuring throat erosion and muzzle erosion on hundreds of barrels and shooting barrels that have been in combat from 3 different continents.
The specific accuracy from chrome lined barrels increasing overtime were from machine gun barrels and it was more than 100 rounds. My bad for not being more specific on that
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