AR15 Varminter


PDA






aaron77
October 1, 2006, 02:26 PM
I am planning on building a varmint/long range rifle on the AR15 platform. Could you guys please sell me on either a 24" vs 20" barrel for the .223 round. It will be a chrome barrel FYI. Thanks...

Aaron

If you enjoyed reading about "AR15 Varminter" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
mrmeval
October 1, 2006, 02:46 PM
Why chrome lined? I'd suggest a 24" stainless from a reputable maker.

aaron77
October 1, 2006, 02:47 PM
why SS over chrome...and could you explain WHY you would choose a 24" barrel over 20"

aaron77
October 1, 2006, 02:55 PM
Let me clarify. Will informed people please provide their opinion on 20 vs 24" barrel length (for the use I specified) AND provide an intelligent argument/theory for their statement. Also, I am curious on opinions re: fluted barrels (in terms of accuracy) thanks...
aaron

648E
October 1, 2006, 03:02 PM
Choose 24" over 20" because it's better! The only reason to have a 20" is the portability which isn't an issue for this use.

Fluting lets the barrel cool down faster, at the same time it makes it get hot faster. It is lighter, and more accurate because it does good things to the rifling.

aaron77
October 1, 2006, 03:08 PM
"...more accurate because it does good things to the rifling."

Could you explain these "good things" further?

What is the gen. consensus re: barrel harmonics in the longer barrels?

Busta Prima
October 1, 2006, 03:45 PM
If I may tag along on this thread with a related question . . . . I was thinking of "varminting up" my AR-15 as well.

What about a scope? Don't you need a scope on a varmint rifle?

How much magnification? What kind of mount? Handle drop in okay?

:)

Don't Tread On Me
October 1, 2006, 04:16 PM
Look, without writing a massive essay on why SS is better than chrome when it comes to accuracy, just realize that NO serious competitors use chrome-lined barrels. That should be enough of a reason. If you want details, do a google search or read the info on barrel maker's sites which explains why.

In a nutshell,

Stainless steel is the choice. Chrome lining distorts the rifling. It isn't as sharp, clean or purely uniform after being chrome plated.

Now, you could take a chrome lined barrel made by Colt, and it will shoot BETTER than a stainless steel barrel made by monkeys in some 3rd world country who make bumpy inconsistent rifling. However, all things being equal..the application of chrome hinders accuracy.


NEXT, barrel length has nothing to do with accuracy. In fact, shorter barrels are stiffer which is more useful for accuracy. 24" barrels are preferred because they generate more velocity, not because they are more accurate. Why would you want more velocity? So you can shoot flatter, which comes in handy for varmints.

Finally, if I were you, I'd choose a barrel made by Krieger, Pac-Nor, Obermeyer, Shillen etc...basically, from some custom barrel maker who will produce something that will shoot great instantly without having you having to jump through hoops to achieve accuracy. Expect to pay $350 or more for the barrel. There are also "varmint" uppers ready to go made by major brands. They are NOT all created equal. Avoid varmint uppers from kit makers. Stick to big brands.

Real accuracy isn't cheap. Or, you can roll the dice on a cheaper barrel and handload and hope you find the accuracy you want. You can believe all the sub-moa fish stories on the internet about how 75% of people's standard USGI barrels shoot 1/4moa....If you're determined to get an accurate rig, skip the internet bull, get something comparable to what the competitors use and guarantee the accuracy.

nico
October 1, 2006, 04:46 PM
It is lighter, and more accurate because it does good things to the rifling.

I haven't seen anything to supporth this, and I doubt that it's true given the fact that I've yet to see a serious benchrest rifle with a fluted barrel. In fact, I've seen comments by a barrel maker (it was Gale McMillan on TFL iirc) that if fluting is done improperly, it can screw up the riflling.

Onmilo
October 1, 2006, 04:52 PM
I like a 24" barrel on my Varmint and target rifle because they generate much less muzzle blast than a 16 or 20 inch barrel no flash suppressor or muzzle brake needed.
The 24" barrel will stabilize a lighter bullet when shot in 1 in 9 or 1 in 10 twist barrels.
As for an increase in velocity this isn't neccessarily so, some factory 50 and 55 grain bullet loadings will actually generate more velocity from a 20" barrel.
I like stainless steel over chrome lined for all the reasons listed in above posts.
If you mainly shoot at ranges less than 200 meters chances are you won't notice a major difference in a chrome lined bore verses a stainless steel barrel.
If you shoot at ranges past 300 meters, or you shoot for extreme accuracy, you will notice the improvement with a stainless steel barrel.
Anybody who tells you different is lying or delusional.

aaron77
October 1, 2006, 05:19 PM
Thank you VERY much DTOM for your detailed explanation...it is precisely the type of answers I am looking for. SS it is. I simply did not want a... "Get a 24" barrel b/c it's COOL" response. I don't expect a dissertation on quantum physics, just looking for some informed opinions and logic to go with it.
So...a 20" barrel is "stiffer" than a 24" (makes perfect sense), and is thereby more accurate (I would assume the difference is nominal; though this is somewhat subjective). My intentions for this build/gun are as follows: 100-500 yd recreational target shooting and varmint hunting, ~1MOA. Would the > velocity/flatter traj. of a 24" barrel be of any significant benefit for my application? Also, is most factory/surplus ammo loaded with approp. propellant to maximize the potential of an add'l 4" of barrel? Any thoughts on this banter are welcome...
aaron

mrmeval
October 1, 2006, 09:46 PM
Exceptionally rude response I think I'll retract my statement and let you do a google search for why.

aaron77
October 2, 2006, 10:06 AM
I do not wish to be rude. Anybody can say..."get XXX product because I like it". Forums are full of these type of people, as I'm sure you know. I would like to hear people's opinions/preferences on barrel length and what logic/belief led you to these opinions. I will not likely receive the information I am looking for unless I make it known what knowledge I am seeking. So...anyone else willing to contribute?

swingcatt
October 2, 2006, 10:57 AM
This is what Bushmaster's faq had to say on the situation. All three questions in this thread are covered in it, plus much more. I'm not saying that I agree with everything they say, notably that the fluted barrel will "last longer", but it's a good place to start, and in the very least fan the flames. :) SC


----

Q. How much difference is there between the use of the 20" and the 24" barrel. I like varmint shooting, and someday would like to compete in DCM matches. Is there a notable difference?

A. With factory ammo, the difference between a 20" barrel and a 24" barrel boils down to about 100 fps (feet per second - velocity). If you handload, you have a greater diversity of loads/powders that will function reliably. The 24" bbl. really does not give you anything extra over a 20" bbl. until you get out to about 400 yards where the extra velocity starts to make a difference. And, the longer barrels do very well with the heavier bullets (69 - 72 grain) at those ranges. If your specific interest is varmint hunting or long range target shooting, you may well benefit from a longer barrel. "DCM" Competition gets very specialized (and very long distance - up to 600 yards) - and when you get to that level, you'll probably want an extra heavy competition barrel - however, "DCM" Competition rules require the use of a 20" barrel. To accurize your DCM use rifle, we also offer 1/4 Minute of Angle Rear Sights with Micro-peeps; DCM legal trigger jobs; "free-floater" type handguard and buttstock counterbalance weights. We have all of these competition parts, so give us a call (1-800-998-SWAT) or see the Competition Parts Section of the Internet Catalog.

------

Q. Does fluting make that big a difference in accuracy?

A. Fluting (machining lengthwise grooves into the outer surface of the barrel) increases the surface area of the barrel - thereby allowing increased radiational cooling of the barrel mass. This process also adds to the "stiffness" of the barrel which enhances its accuracy. A third benefit of fluting is that the barrel is lighter after machining removes the steel in those lengthwise grooves. A fluted barrel will last longer, shoot straighter, and is considerably lighter than a standard heavy barrel. The accuracy gains would be most noticeable at longer distances or to the competition shooter, but for only $50 additional for most Bushmaster barrels, many feel that the benefits of fluting are well worth the cost.

Q. Is a Stainless Steel barrel any better than a chrome lined?

A. Stainless steel is better at preventing erosion than regular 4140 steel, but we use mil. spec. 4150 ordinance steel. Then, our barrels are chrome lined and a chrome lined barrel will easily out-last a stainless barrel. A very good article on barrel manufacturing can be found in the '96 Shooter's Bible (Pg. 33). A typical stainless barrel is made from 416 stainless steel and then broach rifled. This process has been around for about 100 years. Our chrome lined barrels are made from 4150 ordnance steel and then button rifled - a process that's been around for about 50 years. This same process has set virtually every record for the National Bench Rest Association (NBRA). Shilen, McMillan and Browning barrels all use the same process but not the same steel. Mil. spec. calls for 4150 steel - same as used in aircraft machinegun barrels and all military small arms barrels. It costs more but we think its well worth the price. The button rifling process work hardens the bore - making tough steel even tougher. Then, after the barrel is fully machined, it is chrome lined, making it even tougher yet - and virtually impervious to rust or erosion. This chroming process isn't like car bumper chroming. It actually welds each chromium molecule to the steel bore. This chrome lining is far more resistant to wear than a bare steel bore and it gives slightly increased velocity due to the lubricity ("slipperiness") of the chrome. And, you'll see less fouling and easier cleaning with a chrome lined barrel - all in all, a superior product.

http://www.bushmaster.com/faqs/barrels-accuracy.asp

aaron77
October 2, 2006, 01:11 PM
Could some of you who currently own or have solid experience with an AR15 varmiter/target rifle share your experience with the rifle? What kind of groups are you getting at, say 200 yards or more? Could you please provide twist rate, ammo, etc?

ocabj
October 2, 2006, 01:30 PM
I'm not a hunter, much less a varmint hunter.

That said, you'd generally want a longer barrel for maximum accuracy. Depending on your bullets, you'll want the appropriate twist rate.

I have a Adco MK12mod1 18" SPR barrelled upper (which I'm selling, incidentally) that shoots inside 1MOA with 77gr Sierra Match Kings and 25.3gr Varget. 200 yards I get no worse than 1.5" groups.

Again, since I'm not a varmint hunter, I don't know what kind of bullets you'd use. From guys I've met, I usually see them handloading 50gr bullets, give or take a few grains. The most popular varmint uppers appear to be the 1 in 9" twist 24" SS barrels.

But as a target shooter, I'd recommend any barrel with a 1 in 7" twist. 20" for high power service rifle and a 26" barrel for highpower match.

Whatever you do, you don't want chrome lined. Accuracy is more important than barrel life in this case. Or at least, it should be.

aaron77
October 2, 2006, 02:19 PM
thanks for the info ocabj. I guess I'm leaning towards a 24" SS Bull barrel 1:9 w/o fluting. I appreciate peoples personal experiences with products/gear. I want to be able to shoot "bulk"/match ammo reliably, though I know this varies by rifle/load. Keep the good info coming.

Jim Watson
October 2, 2006, 02:26 PM
Anybody who says fluting a barrel "adds stiffness" has lost credibility right off the mark. You cannot make a given barrel stiffer by cutting metal off of it. A fluted barrel is stiffer than a straight barrel of the same cross sectional area. A large diameter fluted barrel is stiffer than a skinny straight barrel, the distribution of metal away from the centerline matters. But it is not as stiff as a large diameter straight barrel.

I would not want an auto rifle for varmint hunting. I barely tolerate one for target shooting. They throw my prepped brass away. I have a nice accurate AR (with long straight barrel) but that is because I had an otherwise unoccupied rifle on hand and all it cost me was a new barrel.

Sleeping Dog
October 2, 2006, 02:55 PM
To me, a 20" barrel is plenty accurate, especially with optics. My next one will probably be a 24 or 26 in barrel, just so I can put a front sight "way out there" at the muzzle and maximize the sight radius, again not necessary if you use a scope.

Jim Watson has a good point about throwing brass. Does anyone make a gas block with a valve, so you can shut off the gas and turn the gun into a straight-pull bolt-action?

Regards.

aaron77
October 2, 2006, 03:46 PM
JW--I had the same exact thought about BM claim that fluting = stiffer barrel. It defies common sense and probably so much more. There is some valid info IMHO in the BM FAQ. Claims like this don't cause me to discount EVERYTHING an individual makes...just makes me a little more cynical/speculative.

I'm not a reloader (yet!) so throwing brass isn't a HUGE concern. I have a Mauser bolt-action .308...I know I won't get quite the accuracy from a SA vs the BA rifle. From what I see/hear, it appears that one can get pretty close though.

aaron77
October 2, 2006, 04:06 PM
JW--I had the same exact thought about BM claim that fluting = stiffer barrel. It defies common sense and probably so much more. There is some valid info IMHO in the BM FAQ. Claims like this don't cause me to discount EVERYTHING an individual makes...just makes me a little more cynical/speculative.

mc223
October 2, 2006, 04:32 PM
Fluting does not = stiffer. Chrome is not detrimental to accuracy.

I have a 24 in Chrome lined barrel that routinely shoots 1/2 in groups at 200yds.

Light bullets slow twist. Heavys fast twist.

Good Shootin.

swingcatt
October 2, 2006, 04:54 PM
More info on barrel fluting. Looks like the key to making a fluted barrel more rigid barrel is that they compare barrels of comparable weight, so if you compare a flutted barrel and a non-fluted barrel that both have the same outer diameter, the non-fluted barrel will be more rigid. However, comparing a fluted barrel to a non fluted barrel that do not have the same OD, but have the same weight, the fluted barrel wins. I'm no metalurgist, but personally I've never been able to tell a difference. SC


http://www.snipercountry.com/Articles/RealBenefitsBarrelFluting.asp
http://www.kriegerbarrels.com/rapidCat/WebPageImages/1246/3392/Fluting72006revb.gif
http://www.fulton-armory.com/fluting.htm

(another interesting thing that the snipercountry article claims is false, is the claim that fluted barrels cool quicker. The author has some interesting theory behind it...like I said before...just more fodder to fuel the flame) :)

648E
October 2, 2006, 05:06 PM
Anybody who says fluting a barrel "adds stiffness" has lost credibility right off the mark

Or not. There's a good explanation for this, I have it in a book at home.

Think about corrugated tin for instance, it's going to be stiffer than flat tin, right?

aaron77
October 2, 2006, 06:17 PM
If you take the cross-sectional measurement of a fluted barrel from "valley" to "valley" (narrowest possible diameter measurement of fluted barrel) and compare that to a straight barrel of that identical diameter then a fluted barrel would indeed be stronger. This is, of course, with all other factors being equal. I suppose the fluted ridges would act as a "scaffolding" for the barrel, giving additional rigidity.

So, will a SS regular bull barrel get hot enough to affect accuracy when firing only ...let's say...8-10 rounds/min for a few hours?

ocabj
October 2, 2006, 06:57 PM
Every good barrel maker will tell you fluting does nothing for strength and little to nothing for heat dissipation. The only known confirmed benefit of fluting is lighter weight.

Firing 8-10 rounds per minute sustained for several minutes (much less an hour) will most likely affect accuracy. How much? It will depend. Too many factors. Barrel quality, ammo quality, weather conditions, etc. Will it affect point of impact? Maybe. Same factors apply. Firing 8-10 rounds per minute sustained for an hour would definitely see accelerated throat wear.

Jim Watson
October 2, 2006, 07:22 PM
mc223, what brand chrome lined barrel do you get .5" at 200 yards with?
That is quarter MOA and would be a great target rifle.

lycanthrope
October 2, 2006, 08:02 PM
You can build an honest to goodness Varmint rifle for under $1200 that will print 1/2" all day. The two easiest options:

Grab a complete Stag/RRA lower complete for about $225 ($320 with RRA two stage trigger).

Slap on a Clark Gator for $879. If you're a member of USPSA ($40) the price goes down $100. You could shave $60 there, at least. The upper is GURANTEED to shoot .5 moa. Mine does.

http://www.clarkcustomguns.com/gatorar.htm

Or.....another choice that is under rated:

Slap on a White Oak Armament match or varmint upper. The Match uppers are $672 and the Varmint is only $590. These guys make CMP rifles to shoot to 600 yards. They have the 1:7 twist barrels that will shoot the heavy bullets and Compass Lake turns their barrels. I had one of their CMP guns. Simply amazing.

http://www.whiteoakarmament.com/

With a White Oak varmint upper and a Stag/RRA lower you would be out $815. Like a true 1lb pull on the second stage? Add Jewell trigger from Midway for $209 You now have a TOP NOTCH AR for under $1050.

Just don't go out and spend $800 for a shelf rifle that will be half the quality.

nico
October 2, 2006, 08:54 PM
A typical stainless barrel is made from 416 stainless steel and then broach rifled. This process has been around for about 100 years. Our chrome lined barrels are made from 4150 ordnance steel and then button rifled - a process that's been around for about 50 years. This same process has set virtually every record for the National Bench Rest Association (NBRA). Shilen, McMillan and Browning barrels all use the same process but not the same steel.

the way they're playing with semantics here bugs me. The process they're referring to is how the rifling is cut before the bore is chrome lined. What this thing basically says is that they use the same method to form their rifling as all these match companies, AND THEN they line them with chrome. However, because of the way it's phrased, it seems like they're trying to have you believe that chrome lined barrels have set every NBRA record, which I'm almost certain is not true.

Chrome lining makes a barrel easier to clean and last longer, at the expense of some accuracy. That doesn't necessarily mean you can't have a chrome-lined barrel on a 1/2 MOA gun. But, all other things being equal, a stainless barrel will be more accurate than a chrome-lined one.

If you enjoyed reading about "AR15 Varminter" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!