Are there any real advantages to having a chromed lined barrel over a regular barrel? Is service life shortened by all that much?

The fully chrome lined barrels are more reliable because extraction is easier and they are also easier to clean more resistant to rust and the barrels tend to last longer.

We were just having this debate in another thread.

As far as I'm concerned, the chrome CHAMBER debate ends here, written by someone who lived through the growing pains of the M16 in Vietnam:

[URL]www.jouster.com/articles30m1/index.html[/URL]

The chrome bore I don't have strong feeling for either way.

Bushmaster:

Q. Is a Stainless Steel barrel any better than a chrome lined?

A. Stainless steel is better at preventing erosion than regular 4140 steel, but we use mil. spec. 4150 ordinance steel. Then, our barrels are chrome lined and a chrome lined barrel will easily out-last a stainless barrel. A very good article on barrel manufacturing can be found in the '96 Shooter's Bible (Pg. 33). A typical stainless barrel is made from 416 stainless steel and then broach rifled. This process has been around for about 100 years. Our chrome lined barrels are made from 4150 ordnance steel and then button rifled - a process that's been around for about 50 years. This same process has set virtually every record for the National Bench Rest Association (NBRA). Shilen, McMillan and Browning barrels all use the same process but not the same steel. Mil. spec. calls for 4150 steel - same as used in aircraft machinegun barrels and all military small arms barrels. It costs more but we think its well worth the price. The button rifling process work hardens the bore - making tough steel even tougher. Then, after the barrel is fully machined, it is chrome lined, making it even tougher yet - and virtually impervious to rust or erosion. This chroming process isn't like car bumper chroming. It actually welds each chromium molecule to the steel bore. This chrome lining is far more resistant to wear than a bare steel bore and it gives slightly increased velocity due to the lubricity ("slipperiness") of the chrome. And, you'll see less fouling and easier cleaning with a chrome lined barrel - all in all, a superior product.

Armalite makes a good summary:

ArmaLite's Chrome Moly barrels have excellent internal surface finishes, and offer excellent accuracy for a reasonable price. Chrome lined barrels offer excellent corrosion protection and slightly longer life expectancy, but are more expensive than unchromed barrels. In addition, the process of electro polishing the barrels, and the chroming process itself, tend to reduce accuracy somewhat. Stainless is easy to process to fine surface finishes, and provides moderate corrosion resistance.

Chrome Moly is thus used for Eagle Arms' standard rifles, for good accuracy for beginners at a low price. ArmaLite A2 and A4 rifles, in either .223 or .308 caliber normally are produced with chrome lined barrels for hard service use under adverse conditions, with stainless steel as an option. All ArmaLite match grade rifles, the Ts and National Match rifles, are made with stainless steel barrels for superior accuracy and decent corrosion resistance

My take on this was to get an unlined barrel, as it saved me about $250 (dpms vs. bushmaster, colt, or armalite).  If and when the assault ban sunsets in about 18 months I can always get a chrome lined and THREADED barrel installed for about the same price, and I can put a fancy flash suppressor on to boot!

Some people claim it helps in cleaning the bore, and I would argue it might, but I also am very meticulous about keeping my weapon clean and maintained, so for me it is a moot point.  As a matter of fact, none of my other rifles or pistols have a chrome bore and they seem to be just fine.

I will say that my DPMS has a chrome bore, and that is VERY helpful as it not only makes it easier to clean off the crud, it makes it easier to see.

Chrome lined or not ? IOM is the most commonly argued point between AR enthusiasts. Honestly I own both and couldn't care less either way. If you have the extra bank, go ahead and spend it on chrome. If you don't, You'r probly not going to suffer any great loss. (unless you'r lazy about cleanig you'r bore ASAP after shooting in humid climates.)

Check this thread out: [url]http://www.ar15.com/forums/topic.html?b=3&f=4&t=159025&w=myTopicPop[/url]

Well go find a Vietnam Vet before 1967 and ask them about the M16A1's, they will tell you that their M16A1's were POS.  That is because the military had not chrome lined the barrel and bores like they had done in the past. Afterwards M16A1's with chrome lined bores are more reliable and can sometimes produce better accuracy.  So if you want to deal with more rusting and pitting, also lose of reliability go with a unchromed, otherwise stick with the chromed.

Unless you are building a bench gun and trying to squeeze every last micro-meter of accuracy out of a gun, GO CHROME OR GO HOME!

Amen [0:)]

Chrome all the way!




...and thats the reason I will never be able to get into competition / tactical / benchrest stuff. I'm just too lazy to take care of them.

Chrome all the way -

Several advantages, no disadvantages except cost.

Mb121 said "Well go find a Vietnam Vet before 1967 and ask them about the M16A1's, they will tell you that their M16A1's were POS. That is because the military had not chrome lined the barrel and bores like they had done in the past. Afterwards M16A1's with chrome lined bores are more reliable and can sometimes produce better accuracy. So if you want to deal with more rusting and pitting, also lose of reliability go with a unchromed, otherwise stick with the chromed."

There were a number of other factors involved in the early M16 problems.

The GI was trained with the M14 in boot camp, got off the plane in Vietnam and was issued the M16 with no cleaning kit.  They were told that it was a .22 and didn't need cleaning.  (sic) This was as much a cause of the chamber corrion problem as any... they came out with the "comic book" cleaning/maint manual for the troops, who were thought too stupid to read regular manuals.

I will not deny that the high humidity and rainfall contributed, it certainly did.

There were serious ammo problems, too.  The ammo in that time period was changed from the originally specified IMR powder to ball powder.  The ball powder burned faster, increased the cyclic rate, and battered the rifle.  But even worse, the powder was REMANUFACTURED.  It was made from old powder that had been stored in hot humid conditions, and was beginning to break down.  One of the components was excess nitric acid.  To neutralize the acidity, they added calcium carbonate.  This would build up in the gas tube and eventually clog it.

They naturally had some serious problems with the rifles.  

Colt sent people to Vietnam for a field trip and they found a number of things.  Yes, dirty and or corroded bores and chambers were found... but the cause was from lack of cleaning.  No cleaning kits, but worse, many of the mags were unservicable.  They were beat up, or had trash in them.  The GI's were never taught to take them apart and clean out the accumulated garbage.

A number of changes were made.  The gas port was resized to work properly with the ball powder.  Proper cleaning kits and instruction, new mag design, a larger, looser chamber, chroming of bore and chamber were other changes made.

To put it all down to just the lack of chrome is to ignore the total problem.  This was just part of the problem, and only part of the solution.  

BTW, Eugene Stoner did not like the addition of the forward assist, nor did he think the chroming was necessary.  He wanted a bad round to be ejected and a fresh rount to be put in, not to jam in a damaged round.  Regular cleaning would have solved other malfunctioning problems.

All that being said, I live in a high humidity area, and I feel stainless is superior for corrosion prevention.  I have rifles with stainless (Oly), chrome lined (Armalite), and unlined chrome moly (J&T w/ Shaw barrel and DPMS.  I use exactly the same cleaning procedures on all of these rifles without problem.  I have not had any extraction problems.

I don't notice any accuracy difference in similar types of barrels due to steel type or chrome.  Naturally, the Ultramatch 1" bull barrel is more accurate, but I attribute that to the diameter, not the stainless material.