Damaged crown on chrome lined barrel AR

[joeranger]

I sent my upper back to the manufacturer and they said the crown was damaged. Since it is chrome lined they cant re-cut the crown. They are replacing the barrel.

Is chrome lining a good thing? How does a crown get damaged?

[csmsss]

Chrome lined barrels seem to be a popular option on AR's these days. Helps with reliability and keeps barrels cleaner, longer.

As for the crown, well, any time you strike a hard or abrasive object with the business end of your rifle, you can damage the crown.

[RC20]

You did not say why you sent it back. Obviously there is a story here to be told.

No info on how new it is.

Crown gets damaged by the barrel being smacked into something that hit right in the muzzle area (either it does not have a flash hider or it was done before it went on or with it off)

If new its possible at factory and not noticed, or in movement and or shipping to dealer if that's how you got it.

After that, it would you hitting it against something or dropping it.

[Jim243]

The most common damage to crowns are done by bore brushes and metal cleaning rods. Over cleaning with a brass bursh and metal stem will scratch the crown to the point that accuracy is effected. Use a nylon brush and plastic or plastic coated cleaning rod to insure no damage is done.

While this may seem extreem, you can re-cut and crown a carbon steel barrel but if it is chrome lined the chrome will not give you a clean cut hence the rebarreling.

Jim

[10-96]

I get the feeling there are at least a few folks out there who go way overboard with the chrome lined bore thing. Yes, I would like to have one on one of my Garands, but other than that- it's my thinking that I haven't ever wore out a regular bbl on either a bolt or semi-auto .223, so why would I get the worries now?

They do make cleaning easier. They do resist throat and muzzle errosion much better. But, the common concensus is they tend to lack a wee bit in accuracy. However the science, mechanics, alchemy, mojo- or whatever means is used to put the stuff in there has gotten much better in recent years according to the interwebs.

Me? If I thought I would manage a Class III license or shoot 10k rounds a year I would consider getting one for 5.56/.223- but otherwise I guess I'll spend that $45 to $90 buck difference in ammo or Dr Peppers or something.

[RT]

in the future, send it to ADCO, they can cut and recrown it

[madcratebuilder]

I get the feeling there are at least a few folks out there who go way overboard with the chrome lined bore thing. Yes, I would like to have one on one of my Garands, but other than that- it's my thinking that I haven't ever wore out a regular bbl on either a bolt or semi-auto .223, so why would I get the worries now?


I tend to agree. CL barrels are great if you shoot corrosive ammo or operate in a harsh environment.

[Eghad]

for the average use who takes care of his stuff a non chrome lined bore is nothing to worry about.

[joeranger]

Thanks everyone. ...and here is "The rest of the story".

I wanted to build a custom AR for long range varmint hunting but I also wanted to have the "look" of an ultra-tacticool sniper system and fire 5.56 so I could buy cheap surplus ammo and do it all on a limited budget. I love my AR in the same way guys love their first car that they "had to have" but leaks oil and sucks money out of your wallet.

I bought a DPMS lower, a preconfigured upper from Model1Sales, a scope from eBay and a bunch of factory reject ammo. So it shot like crap. Dinner plate groups at 100yds. So;

I replaced the scope with a decent 10x super sniper.
I replaced the scope mount with a good 1 piece heavy mount.
I bought good ammo
I bought really good ammo (black hills)
I tried to break in the barrel by cleaning frequently.

I was using my old cleaning kit from the Army (with an extra section due to the 24in barrel) I am guessing that caused the damage.

I made rookie mistakes but learned from them. A friend of mine just spent a fortune on a Lewis Machine AR but I bet I enjoy mine more.

I still need to replace the trigger but with a new barrel this should be good to go. I know Model1Sales has some critics here but they have been awesome to work with.
...and that is the rest of the story:)

[Mrgunsngear]

I'm curious to hear how the crown was damaged if the flash hider was on... The only time I saw this was a guy who cleaned his AR with actual dental tools (the ones that have a rockwell hardness that is much tougher than your rifle steel). He scratched his crown all up and it was damaged, no doubt. Did it matter as far as shooting it---probably not...

[tim s]

The most common damage to crowns are done by bore brushes and metal cleaning rods. Over cleaning with a brass bursh and metal stem will scratch the crown to the point that accuracy is effected. Use a nylon brush and plastic or plastic coated cleaning rod to insure no damage is done
Quote:


FYI, you will never harm a barrel with a quality brass brush and nylon will often not be enough to break up solvent softened carbon fouling. Primary damage can result in pushing a rod well past the crown and riding over it repeatedly.

[tobnpr]

I thought that chrome lining was done primarily on older milsurps where corrosive Berdan primers were used- like AK's- to resist the corrosion and extend barrel life.
What's the practical advantage today?

[HKGuns]

What's the practical advantage today?

Nothing. It is all part of the "Mil-Spec" craze that has infested the AR rifle community. Colt makes them that way for the Military so it must be a requirement for everyone and anything other than chrome lined is inherently inferior.