Just curious , is a chrome lined barrel less accurate than a standard chrome moly barrel in a AR15? Other than the obvious advantages of chrome, cleaning and break in, any differences in life expectancies?

Slightly less accuracy potential w/ the chrome-lined bore, but much longer life expectancy.

Mike

Troy: is there much accuracy difference between the various chrome barrel makers? I am currently considering a DPMS 1-7 16" M4 vs. a Colt (which is more expensive).

My experience is that there is no discernable accuracy difference between nonmatch chrome lined and regular barrels.

[heresy]There also does not seem to be a significant or even discernable difference in reliability.[/heresy]

There probably is a difference in the life of the barrel, but most people would not shoot out a regualar barrel during their lifetime.

I hear Krieger barrels have legendary accuracy (everyone who has one is happy with them).

The best accuracy I have attained is with a RRA 1/8in twist SS DCM barreled DCM upper.  It would shoot 4/10's of an inch bench rested with the match grade iron sights.

My Bushmaster 14.5in HBAR with SE Vortex would shoot half MOA with my ACOG attached and using a RAS II.


I think chromelined barrels from Bushmaster with a heavier contour should be capable of 1/2 MOA.... The SS match barrels will probably do 1/4 MOA or better with good ammo and a scope.

So really the debate is over 2 things:

1  1/9in twist being std in chrome lined barrels with contours heavy enough to shoot well and the plethora of speciallized twist rates availible in the Match grade SS barrels.

2  wether or not 1/4MOA is worth the difference in price and slight difference in accurate life.

[Notice I say slight... the bushmaster is allready shooting 1/2MOA and groups will open to about 2-3MOA by about 7000-10,000rds

The Krieger is shooting less than 1/4MOA from the start and I'll bet when you get to 10,000rds it will still do better than 2.5MOA for sure.]

[b]Accurate life for chrome bored military guns and Competition match rifles are 2 different things

on a serious competition gun 1MOA might be the end of a barrel's claimed "accurate life" .[/b]


"Chrome-lined barrels are also much more resistant to corrosion and are much easier to clean. "

I haven't seen a high grade SS barrel rust or corrode.  

I have seen many military Colt barrels get some surface rust (esspecially around the gas-block and forward of the sight tower as that is where they are most likely to be touched) after a week of rain in the field though.

Most hand lapped competition barrels esspecially those that have been cryoed- will clean in 2-4 patches max. My RRA SS 1/8 (after 50rds at the range would give me clean patches after 2 patches)
[b]I also reccomend chrome lined for duty guns as full auto fire and SS are not an excellent combination.[/b]

"If it wasn't needed, the military would have dropped it, saving a LOT of money. Yet most modern military rifles have chromed barrels. You think there might be a reason...?"


Yeah 3 reasons.

1 Dumbass GI (sometimes this is me when I'm lazy) is smart enough to know the inside of the bore can't be inspected (so all he does is run a dry patch through it to get the debris out and then turns it in after meticulously cleaning all exposed surfaces.)

2 Chromed chambers offer added lubricity for easier extraction of cases. (so does stainless but SS is not a great idea for select fire weapons)

3 (really ties into 1) rusted bores are ruined barrels so $25-50 worth of chrome plating might save the cost of a whole new barrel


[b]Often when the barrel get's up around 7,000-10,000 rds of harsh use the chrome plating becomes damaged and sometimes flakes peel off and damage the bore (I am not a scientist but I am sure something like this has to be going on or the chrome bore that used to clean up in 2 patches would not now take 50-100 patches to have one come out clean) this is probably why chome lined bores accuracy really deteriorates dramatically (IE from 1/2MOA to 3-5MOA) when a SS barrel's deterioration is on a scale of about half that.[/b]

Chrome it is! Thanks

Hard chrome does not peel or flake but can wear away.  This is NOT decorative chrome.

Yeah I guess I subconciously straid fro Chrome moly.

To answer your question Chrome moly sucks.... I wouldn't want a chome moly barrel without chrome lining.


SS does not rust true SS is 416 and higher grades. 305 is "rustless iron" 316 is still going to rust.

I think Krieger uses 416SS

Good luck getting 416 to rust and corrode.

You can have my share of chrome. I'll stick with SS. [;)]

xyzzy45,

The DPMS barrel you mentioned is actually a special run barrel that is only made by CMMG. It is as close as you can get to a "real" M4 barrel without having Colt stamped on it. It has all the same goodies as the Colt.
1) 1-7 twist
2) Chrome lined chamber and barrel
3) 4150 steel rather than 4140 steel
4) M4 feed ramp cuts (extended in their uppers)
5) Step down barrel profile for M203 mount
6) Chambered for 5.56 NATO, not .223
7 Available in 16 or 14.5 inch length.
The only thing I would like to see CMMG change is the cast front sight tower, and replace it with a milspec forged one.
CMMG.com has them on their websit. Good people to deal with.

boomer632: would those feed ramps cause a problem with an upper not setup for them?

thanks