M249 Based barrels

[kennygss]

Hi guys,

I have seen it discussed that M249 based barrels offered by some are a better option for the high use AR. Is there a large sacrafice in accuracy by using the chrome lined SAW type barrels. I can see the benefit for full auto perhaps with the heavy chrome lining.

Thanks!

[boomfab]

Like the noveske m249 steel barrels? *In general* you will give up some accuracy over a SS match barrel. But not always. You may get a m249 steel barrel that shoots 0.75 MOA or better.

[raz-0]

In for any sort of authoritative answer, or even anecdotes from people who shoot rifle well and often.  It seems there are a lot of these cold hammer forged ar barrels showing up on the market. Probably all made by FN, probably all from 249 barrel blanks.  I feel your pain. I've been looking for an answer myself, and have found nothing authoritative other than there's sound reasons behind why cold hammer forging will make it tougher and that a thicker layer of chrome plating is tougher than a thinner one. 

From digging through every forum I can think of and google and bing, people seem to be happy. But those people seem to not be concerned or not be capable of shooting things accurately.  So beyond the unspecified "just as good",  or "woohoo I used to shoot 6 MOA gorups, now I shoot 4 MOA groups", I never really found an answer. 

Closest thing to an answer I got was that tit shouldn't be meaningfully worse than a standard chrome plated, button rifled,  5.56 chambered  barrel. If you would be comfortable with that, then the CHF with thicker chrome lining should fill the bill and last longer. 

I'm building a new upper, and going to order one of the new wave of CHF barrels. It's like $70 more than the button rifled version which my friend has of the same brand, and then I can compare the two. 

[boomfab]

I have an FN SPR with a factory CHF chrome lined barrel that shoots ~0.4 MOA or better. It's has a very heavy profile barrel.

My brother just got one of the 20" BCM CHF CL barrels (made by FN). I'm curious to see how it shoots.

[Beretta Lover]

My limited first hand experience with CL FN barrels was positive. No not as.accurate.as a JP barrel but easily 1.5 mow from a 20in barrel

[DocMedic]

I have an FN SPR with a factory CHF chrome lined barrel that shoots ~0.4 MOA or better. It's has a very heavy profile barrel.

My brother just got one of the 20" BCM CHF CL barrels (made by FN). I'm curious to see how it shoots.

SPR's use a 240 barrel. I agree though I get under .5MOA out of mine, but even fluted, the barrel still weigh a little to much for 3gun.

[kennygss]

Thanks for all replies.

[fastmtnbiker33w]

My dad spent about an hour talking to me on my cell about this a couple weeks ago. He has one of FN's tactical bolt guns that uses a machine gun barrel. He was all concerned because when he got it it shot like crap. He spent a bunch of time cleaning the barrel and then re-breaking it in by shooting 10 rounds then giving it another thorough cleaning (several times) and it finally started to group well. He's shoots all different long range type competitions and has been to Camp Perry several times so I trust his knowledge and judgement.

He made it sound like the chrome lined barrels are hit or miss when it comes to their finish. Some need some serious breaking in to get good accuracy. The first 10 shots should be followed individually by a good cleaning with Hoppes #9. Let it sit in there for a few minutes the keep running patches until the patch comes out clean. I just did this with my Ruger 556 chrome lined barrel. The first 10 rounds sucked because cleaning at the range is just a pain. After I went into my 10 round sets/groups, the third group group really started to tighten up. Cleaning was still a pain....but worth it.

Some chrome lined barrels are quite rough, so breaking them in is important if you want accuracy.

[Kevin J]

Accuracy and chrome lining can be hit or miss. From the samples I've dealt with, most of the accuracy problems have been somewhat related to the crown however. Testing before and after adding a 11 degree crown has shown some pretty significant differences. My theory is how the barrels are set up for the crown at the factory. I will also add that some of the chrome barrels I've worked on could not be helped. Stainless or CM based blanks will always perform more consistently blank to blank.

We have team out here running the FN precision auto loaders and the two that I've seen do some very impressive accuracy. To fastmtnbiker's point though, they all got somewhat of a break in.

As for using machine gun barrels.....

These barrels are AR barrels, the only difference is the chrome depth and material spec. There is a lot of argument over CHF vs. Cut rifling. I think the major reason there are so many CHF barrels out there now is the number of domestic hammer forging machines has increased with DD bringing their gear on line. But as far as I've been told FN manufacturers the vast majority. Either way, they are very good barrels and Ive tested a few that shot some pretty amazing groups. The Noveske N4's that I have tested have usually been very accurate barrels.

Edited December 4, 2010 by Kevin J