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-   -   Chrome & Barrel Rifling? (http://www.firearmstalk.com/forums/f20/chrome-barrel-rifling-74071/)

Triumphman 10-10-2012 02:51 PM

Chrome & Barrel Rifling?
 
I know about the ease of cleaning and durability of chrome lining of barrels. My question is, whether the manufacturer, over sizes the barrel bore before they button rifle it, to allow for chrome thickness?
Or, they just apply the chrome in the bore of a standard barrel, and chrome builds up on the grooves/landings and leaves less rifling, and that's why accuracy is supposably affected with a chrome lined barrel. I'm new to AR's but still learning.
Del

primer1 10-10-2012 04:58 PM

Tried Google? I would think they would have to oversized before chroming. The chrome is going to be be at least a couple thousands of an inch thick, multiply times two and the pressures would be too high from the tight bore.

bige91603 10-10-2012 05:12 PM

I had heard from some gentleman who are much wiser than I that they slightly over size it to compensate for the chrome, thus why some say that they are less accurate than non cl. Is this true? Some will agree and others won't

primer1 10-10-2012 07:10 PM

Quote:

Originally Posted by bige91603
I had heard from some gentleman who are much wiser than I that they slightly over size it to compensate for the chrome, thus why some say that they are less accurate than non cl. Is this true? Some will agree and others won't

The people on the AR threads mostly agree the chrome bores are not as accurate.

kytowboater 10-10-2012 07:37 PM

Ah yes, but does the benefit of the chrome out weigh the negative impact on accuracy??

bige91603 10-10-2012 07:51 PM

Quote:

Originally Posted by kytowboater
Ah yes, but does the benefit of the chrome out weigh the negative impact on accuracy??

It matters what you're using it for, chrome lined is strong and hold up to more use and prolonged use

JonM 10-10-2012 08:02 PM

There are schools of thought on this topic. Not all chrome lining is equal. Some is really thin others thicker. The main proboem is that chroming process doesnt leave an even coating on the bore. There are high and low spots but this is due more to the actual care taken to rifle the bore itself than any real flaw in the lining process.

Take the same bore chrome vs un chrome made on the same day etc. They will shoot the same. The highs and lows left by the chroming process are so small that it wont affect anything. An innacurate barrel is an inaccurate barrel.

How the barrel is cut, who is cutting it, the technique used, barrel material all that is the real key to accuracy.

My bcm middy is hammerforged, chrome lined chamber and bore (some barrels only chrome the chamber) and is a sub moa gun out to 300yds.

ZeusEcho 10-10-2012 11:59 PM

Quote:

Originally Posted by JonM (Post 971748)
My bcm middy is hammerforged, chrome lined chamber and bore (some barrels only chrome the chamber) and is a sub moa gun out to 300yds.

With what ammo might I ask?

I know you are a damn good shot ;) but I'm not getting close to sub MOA at 100 yards with my BCM hammerforged middy. I've only used Federal 62gr M855 and Remington 55gr 223. Got about 400 rounds through it and it's about 1.5-2 MOA at 100 yards. I was using a 4-9x40 Bushnell Banner scope, bipod, and rear sandbag.

hockeyjr1 10-11-2012 12:39 AM

Quote:

Originally Posted by ZeusEcho

With what ammo might I ask?

I know you are a damn good shot ;) but I'm not getting close to sub MOA at 100 yards with my BCM hammerforged middy. I've only used Federal 62gr M855 and Remington 55gr 223. Got about 400 rounds through it and it's about 1.5-2 MOA at 100 yards. I was using a 4-9x40 Bushnell Banner scope, bipod, and rear sandbag.

You problem is your ammo... Try some match stuff and see what you get.. Also if you have a 1/7 twist barrel you can stroll into the 70+ gr bullets which should be much more accurate..

JonM 10-11-2012 02:02 AM

Quote:

Originally Posted by ZeusEcho (Post 972006)
With what ammo might I ask?

I know you are a damn good shot ;) but I'm not getting close to sub MOA at 100 yards with my BCM hammerforged middy. I've only used Federal 62gr M855 and Remington 55gr 223. Got about 400 rounds through it and it's about 1.5-2 MOA at 100 yards. I was using a 4-9x40 Bushnell Banner scope, bipod, and rear sandbag.

69 and 77 grain smk over w748 powder max load from the sierra manual. and ss109 over w748 i use data from hornady 62grain hp loads

i dont get that with the acog but i do when i put my nightforce nxs f1 for accuracy testing

you need to handload to get the best out of accuracy. blackhills match ammo is the only thing out there that even resembles what is possible with careful handloads

55grain fmj sometimes hits 1-1.5 at 100 but 2inches is the norm and thats within the 3moa military standard for an issue rifle with that bullet

if your testing by holding the gun yourself you need a really good front rest and a good sand bag for the rear. caldwell basic rests are great for that run about 20$ for their elcheapo front rest which is a great one.

the stock bcm trigger is not a good accuracy one and that holds things back a lot. i dropped in my rra two stage for testing


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