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Posted: 6/3/2004 9:52:14 AM EDT
As I've said a dozen times on different threads, I am building a dedicated "Short Varmint Upper" (SVR  ) that will have a 16" free floated barrel, an illuminated low power scope, a bipod and a light. The upper will be used for shooting armadillos, coyotes (if I'm lucky), and anything else that I might find myself "hunting" with a .223/5.56. With that in mind, I'd say that the rifle itself (without me behind it) needs to be able to do at least MOA, and I anticipate shots out to 200 - 250 yards would not be uncommon. I will be shooting from prone or seated using the bipod as much as possible to minimize wobble and optimize accuracy.Given two otherwise identical barrels... specifically, RRA/Wilson 16" mid-length 1:9 chrome molly barrels, one chrome lined, one not chrome lined, would there be a noticeable difference in accuracy between the two barrels? Thing is, I already have a mid-length chrome lined 16" barrel that's been turned to approx. SPR profile and then fluted under the HG by KKF. That whole rig cost me around $300 plus a 3 month wait. I then decided I wanted a lighter barrel for my "General Purpose Carbine", so I got a gubment profile middie from ADCO. So here's this fluted barrel laying around already that I have $300 invested in... I could sell it, along with all the handguards, sights, delta ring, flash suppressor, gas tube etc. that I've purchased additionally and maybe get $250 - 275-ish for it, then turn around and get one just like it that's not chrome lined (or fluted) for $150. Or I could use this barrel to build the "SVR", but if it's not going to be any more accurate than the lightweight GPC, what's the point? I guess what I'd like to hear is from guys who routinely get sub-MOA from their chrome lined barrels, and I'd like to hear what type of accuracy those with chrome moly barrels are getting. I've never had a barrel that WASN'T chrome lined, but then I've never had an AR15 that was sub-MOA accurate either. Thanks for the input. |
Depends - how good of a shooter are you? Also what position will you be shooting from? Personally I don't see any difference out to 100y, at 200y I'll see some IF I'm shooting prone or from a bench. If its a 300-400y varmint rig consider getting a decent stainless; otherwise a Bushy chrome lined should be good for 1moa with good ammo. |
Eh.... I'm not bad, but I can't get sub-moa from a sub-moa rifle yet. Thing is though, using my math, I figure that if I'm a 2-moa shooter, and use a 2-moa rifle, that's a 4-moa spread. So with that same skill (or lack of) and get a 1-moa rifle, then that STILL cuts my groups in half.  I'll be shooting with a bipod mostly from prone, seated, or bench. Very little free hand with this one.
I thought about it, but since the stainless are all 1:7 or 1:8, and I plan on using GA Arms 55gr Noslers, I really wanted the 1:9 twist. I think 300 is about max for my shooting distance with this rifle. THanks for the quick response. |
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I think that chamber dimensions are one of the biggest influences on barrel accuracy. Followed closely by things like crown, bolt true and rifling smoothness. The thing about most chrome lined barrels (note that I avoid the sweeping generalization of "all") is that they tend to have a big gaping NATO chamber and a throat that a porn star would envy. This is not conductive to great accuracy but it helps a great deal with feeding reliability. I'm really not sure about RRA barrels. I’ve heard that they use some sort of hybrid NATO/SAAMI chamber that allows you to shoot NATO spec ammo without the over-pressure and feeding issues seen in SAAMI barrels. I can’t imagine that solution giving you much more accuracy than you would see with a standard NATO chamber. If you really want to build a super accurate gun, I would suggest using a barrel with a tight SAAMI spec chamber and some form of cut or "single point" rifling. Then have it assembled by somebody that can true up the bolt face/crown and get the headspace right. Hope this helps |
My brother has a 1:7 twist Colt barrel - bare chrome moly bore with a chrome lined chamber. It shoots sub moa groups at 100 & 200 yards with 55gr ammo from a benchrech. Twist shouldn't be an issue for 55gr. |
Sub-moa, not only was your post very informative it was very entertaining.  Now forest, do tell, are you talking about 5 shots? Are you talking about irons? what kind of ammo are you talking about? And what is his trigger like? I'm very interested, because I have a bone stock 1/7 colt and The best I've done is 2-3/4" with hornady 75 hpbt match. 
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Yes
As I posted, rifle was put in a bench rest. Basically it removed 'the human element' and was done to determine the capability of the rifle (My brother had it made for DCM competition)
Its been 5-6 years, might have been Black Hills 55gr.
Very nice, its a two stage match trigger. I can ask my brother the brand if you want. I'm not much into 'DCM' configurations - but this is one nice shooting rifle.
See that is the difference. While all the barrel on my brother's upper are 'bone stock' - the parts were hand picked off the assembly line and assembled by one of Colt's R&D people (a man by the name of Ron Giddish - who's since retired). He built many of the ARs for the members in the rifle club my brother belongs to. Not all Colts will shoot that well - nobody has claimed otherwise. But 1:7 twist does not have a significant impact on how well it shoots 55gr. If the barrel is a 'good one' it will shoot 77 gr & 55gr well - if its a 'bad' one it will never shoot well. |
| Sorry about that, I didn't understand what bench rest was to you. To me, benchrest is some form of shooting off the bench with aids. There are alot of variations of "aids" out there. The only thing I've ever used is sandbags. I understand there are probably better rigs, but I don' t know If I want to invest in one yet. I like the idea of shooting without any artificial support but it's hard to get a good idea of which ammo is best without doing some kind of bench rest. In my opinion. I'll have to make friends with someone who's got this kind of equipment to test my gun. eh? |
If I were using SS193 ball ammo maybe, and even then, it's not "FAR" below the fragmentation threshold.... Here's the fragmentation chart from the Ammo Oracle:  Note that even below 2200fps, there is evidence of a piece of bullet breaking off, which suggests that the bullet is still yawing. But I plan on using PREMIUM ammo with Nosler bullets anyway, so I expect a lower fragmentation threshold... Also remember, these will mostly be armadillos which can be humanely killed with a .22. |
Maybe curts never heard of a "Soft Point". Or a "ballistic tip". Or a "hollow point", or a "open tip Match" or a "lead bullet" or a.... is that all of them? Frangible. That would be interesting. I'm just poking fun curt . But seriously, alot of us shoot bullets other than fmj, especially to hunt with. Not that I'm against it. The DNR in my state is against fmj for large game. Not varmints though. FMJ away!!!!!! I'm sure a .22 hole all the way through would probably do the job. 
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"Given two otherwise identical barrels... specifically, RRA/Wilson 16" mid-length 1:9 chrome molly barrels, one chrome lined, one not chrome lined, would there be a noticeable difference in accuracy between the two barrels?" Get an RRA SS heavy barrel with the quality of their DCM barrels, and you should be able to shoot 1/4in-3/8inch groups at 100yds with decent optics. Chrome lined heavy barrels are good for 1/2inch to 1inch groups at 100yds, and if you add a G6 Vortex FH odds are your groups might shrink to around 3/8-1/2inch. Your talking about a 1/2MOA difference, and if you get a crappy model 1 Sales SS or Chrome moly unlined barrel, you might see similar results as with a chrome lined Bushmaster or RRA. I would say the difference in accuracy is only worth mention when you are talking about higher end non-lined barrels, like Douglas and Krieger. In that case you'll probably see a 1/2 to 1MOA difference, and that could be signifigant depending on what you are doing. I had a model 1 Sales SS 1/8 DCM upper and a RRA SS 1/8 DCM upper, and there WAS NO COMPARISON, the Model 1 Sales shot 3/4-1.25MOA while the RRA consistently shot under 1/2MOA with the irons. |
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The chrome lined barrels with fluting most often have the flutes added after the bore and rifleing are cut, and that is suspected to put stresses into the barrel and can adversly affect accuracy, I have a fluted Dissy Hbar that shoots 3/4MOA, and my 14.5in HBAR without flutes would do 3/8MOA with a Vortex FH. I'm not sure if it is the fluting but I do think it probably is. The only way to get the flutes cut prior to drilling and rifleing is to buy Douglas or Krieger (top shelf brands.) |
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