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Posted: 7/24/2015 7:23:09 PM EDT
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What are the pros and cons of a chrome moly HBAR vs a stainless HBAR in terms of target shooting?
Thanks |
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Quoted:
What are the pros and cons of a chrome moly HBAR vs a stainless HBAR in terms of target shooting? Thanks you may be off on the wrong foot because of the use of the word "chrome" in two different aspects of the barrel specification. so let's see if we can clear that up a bit. there are two pieces to this puzzle: (1) the barrel material itself, and optionally (2) the plating which can be applied to the bore and chamber. (1) barrel material: practically all steel AR15 barrels are machined from type 4140 or type 4150 ordnance steel. these steels are alloys which include chromium and molybdenum, and are typically referred to as "chrome-moly" steels. hence, almost all steel barrels are chrome-moly (CM) steel barrels. some steel alloys for barrels include other constituents such as vanadium (typ. for CMV machine gun barrels). moreover, barrels can of course be machined from other materials, including stainless steel types 415, 416, 416R, or similar. in any case, the barrel vendor should be able to furnish information about what material a given barrel is machined from. if they can't, they have no idea what they are doing and you should look elsewhere for a quality barrel. (2) plating: once machined, the barrel can undergo various secondary operations. one such operation is chrome plating (aka chrome lining) of the bore and chamber. in this case, a very thin layer of chromium is selectively electroplated to the bore and chamber. the chrome plating increases surface corrosion resistance and decreases surface friction. however, the deposited chrome plating thickness is not perfectly uniform and this has led to the assertion that chrome plated barrels are slightly less accurate than non-chrome plated barrel. in most cases, the slight loss of accuracy is far outweighed by the operation and maintenance improvements resulting from chrome plating. for this reason, the majority of AR barrels have chrome plated bores and chambers. only selected "target" or "match" barrels usually lack chrome plating. note that chrome plating can be used whatever the barrel material is -- CM 4140, CM 4150, and even SS 416R -- but it is primarily seen on CM 4140/4150 steel barrels since stainless steel has an inherent corrosion resistance. so: a) there are CM "general purpose" barrels which have chrome plating, and are intended for all around use. b) there are CM "match" barrels which lack chrome plating, and are specifically intended for target shooting. c) and of course there are stainless "match" barrels which are also specifically intended for target shooting. whether b) or c) is "better" than the other is more dependent on the barrel maker and the ammunition used than the barrel material itself. with regards to lifespan, at current ammo prices, you spend about the same for 1K rounds of plinking ammo as you would spend for a decent quality barrel. hence by the time your barrel is shot out, you will have spent between 10 and 20 times the cost of a replacement barrel just on match ammo. so the barrel cost and lifespan is actually a very small part of the economics, at least in 5.56mm/.223Rem shooting. as for any barrel "lasting" a long time --> either a non-plated or chrome plated barrel will last as long as you want -- the accuracy degrades because of throat erosion and land wear. how long that takes is a function of your accuracy requirement. if you are a top tier benchrest shooter, you may find that 2000 rounds is your limit. if you are a 3 gun affecianado, you may find that 6-8K rounds is where you are starting to run into trouble. and, if you are just plinking at pepsi cans out in your backyard, you may find the barrel is ok out to 12K or even 15K rounds. ar-jedi |
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ok, above, i covered barrel material. here i will cover "HBAR".
in the context of the AR15 system, a heavy barrel (HBAR, nominally 0.750") profile does not provide a lot of net benefit to anyone other than the guy machining the barrel. an HBAR profile is less expensive to make compared to other profiles. but there is really not any material advantage to HBAR over other target barrel profiles, and if you are considering an AR15 you may want to look at profiles that are lighter. examples http://www.ar15barrels.com/profiles.shtml next you are going to ask about length... 
IMHO at longer ranges: 20" with rifle gas system. shorter ranges: 18" with midlength gas system. eg http://www.rainierarms.com/noveske-spr-5-56mm-barrel-18 ar-jedi |
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Thanks for that info. Heard the term 'chrome moly' for years but never knew what it meant in terms of barrel construction.
Mostly cans and paper targets is what would be shot. I am leaning towards a 1in 8' twist stainless with match crown. This would be with A2 sights. The gun is a 20 inch AR and the barrel would be a replacement. Current barrel is also an HBAR profile. I think stainless barrels are known for their accuracy? |
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Quoted:
Thanks for that info. Heard the term 'chrome moly' for years but never knew what it meant in terms of barrel construction. Mostly cans and paper targets is what would be shot. I am leaning towards a 1in 8' twist stainless with match crown. This would be with A2 sights. The gun is a 20 inch AR and the barrel would be a replacement. Current barrel is also an HBAR profile. I think stainless barrels are known for their accuracy? is your current setup free-floated? are you planning on going that direction? ar-jedi ps see also http://www.whiteoakarmament.com/xcart/home.php?cat=250 |
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A CMV 4150 match barrel that has been QPQ SN treated (hot salt bath nitride with quench, polish, quench process), may be the best of both worlds. You have the pristine, match grade rifling undisturbed by plating, comparable to stainless, and a hardness comparable to chrome lining, with very extended barrel life.
There are now specialty companies that are nitride treating match stainless barrels to extend useful life. |
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