Chromed lined barrel or not?

[VA Bigbore]

What are the thoughts on needing a chrome lined barrel for the Grendel (or any other cartridge for that matter) in the AR. What are the benefits of having the barrel lined and just shooting a standard rifled barrel?

[bwaites]

Chrome lined barrels will last longer, at least in theory.

That said, with a 50,000 PSI limit, Grendels are a long way from being barrel burners, the barrel in my first Grendel was still sub MOA at almost 6000 rounds.

If you are a heavy shooter, chrome makes sense.

They generally are not considered to be as accurate as stainless barrels, however.

A new option is melonited barrels, which might offer all the advantages of chrome, with none of the tradeoffs in accuracy. The jury is still out.

[VASCAR2]

Chrome lined barrels resist corrosion better especially in wet tropical condition or where weapons are exposed to salt water. Chromed bores improve feeding and especially extraction in semi and auto weapons. Generally the chrome is applied after a barrel is rifled so a non chrome lined barrel tend to have a higher tendency for better accuracy. In a military application chrome lining the chamber and bore makes sense. Since the advent of non corrosive primers barrels have less tendency to need immediate cleaning and generally last longer. A good chromed lined barrel can have very good accuracy and sustain more rounds down the barrel before accuracy deteriots than a non chrome lined bore/barrel. Chrome lined barrels supposedly are easier to clean but there is a point where the bullets going down the bore can wear through the thin chrome lining. Each individual barrel is unique and some are just better or worse in the batch. I've used chromed and non chrome line barrels in LE where a weapon is stored in a vehicle for long periods of time. Both types of barrels performed the same for me however I've yet to wear out any barrels.

[VA Bigbore]

Ok thanks guys. You all have confirmed what I guess I already knew, but wondered if there was more to it than this. All my other guns, .25 WSSM upper included, is not chrome lined and there are no issues. I just thought it "different" that a builder offered both versions. I think I'll stick with the non-chromed bore and be just as happy. Thanks again.

[LRRPF52]

The US Military did an extensive study in the 1950's I believe, and looked at nitrided barrels, exotic alloys, barrel liners, Nickel Boron chambers, and about every advancement in metallurgy that had been introduced up to that time. For full-auto use, it was determined that chrome-lining helped maintain the bore and rifling longer than others, when abusive levels of full-auto fire were conducted. The combination of shock force, heat, pressure, and friction seemed to be dealt with best by chrome-lined barrels, at least for barrels that could be reasonably mass-produced.

For civilian, non full auto use, even a 4140 CMV steel is plenty fine, especially when nitro-carburized (Melonite/nitrided). I have personally run two AR15's with 4140 CMV barrels past the 10,000 round mark, where they had finally degraded in accuracy so much, that they couldn't reliably place a round on a 12" steel plate at 100yds anymore, and were retired. One was from a JT upper, and the other a Rock River Arms mid-length 16" heavy. All my other barrels have been 4150 CMV chrome-lined, stainless, or Melonited 4140 CMV, and I like the Melonited ones so far, as I do the Chrome-lined for high-volume guns.

I saw a Bushmaster 4150 CMV chrome-lined barrel at one of the courses I ran with over 26,000 rounds through it, and the first 4"-5" of rifling were pretty much gone. Owner replaces ejector spring, extractor spring, and recoil spring at proper intervals, and lost 2 lugs during that course, and is still driving on with that barrel and a new bolt...which shoots well enough for close-range work.