I have a SIG M 400 with an ALG ACT in it, and its very accurate, but is limited somewhat by the trigger and somewhat by the Burris AR 332 mounted on it. Great 300 yard gun, but not a long range or high precision piece.

I have a couple of lowers to build, and would like to build one of them into a varmint or precision AR. Now, I don't compete, and I have 53 year old eyes, so I'm not looking to spend a couple of thousand dollars on this gun with optics. I'm likely to put a 4 x 16 or 6 x 24 scope on it, probably a good Nikon or Vortex with turrets. I'm thinking a 24 inch bull barrel, as this thing isn't going to be carried very far, I'll probably want a rail that I can put a bipod on. I plan to drop a decent trigger into the lower, and will likely use the BCG and Charging handle from my M 400 at least for now as the rifle won't get all that much use, and pick up a dedicated bcg and charger later.

Just a quick survey of available uppers shows Blackthorn at $259 up to White Oak at $650+. I could also order a barrel and have some local guys build me an upper. I have a 9mm upper from a local shop and it is great.

What recommendations do you all have for this rifle? Where am I good, where am I off base, what should I spend, how should I do this, and any thing else you can think of that will make this a fun project.

I'm looking for a modestly priced, long range, accurate shooter.

Thanks.

The heart of a precision rifle is a good barrel with the proper chamber.

If you will be handloading to chamber dimensions, a 5.56 chamber may work. If you're relying on factory 223 match ammo, get a barrel with a 223 chamber, or choice #2 a Wylde chamber.

Look for a stainless steel barrel. No chrome lining. Twist between 1/8 and 1/7. Some of the better barrels have 1/7.7 twists -- I have one and it shoots really well.

You want a heavier profile barrel. Bull barrel (aka truck axle) works, although not necessary. My most accurate barrel is a 20" with an H-BAR DCM profile. It's not light, but it does taper. It outshoots my 24" bull barrel from a lesser barrel maker.

Muzzle velocities for 223 loads continue to increase for barrels longer than 20", but the speed gains per inch fall off. My 20" produces just as fast MV as the 24" for 69 and 73 grain loads. However, the 24" has higher MV for 40-55 grain loads and 75-77 grain loads. FWIW, when I shoot out my 24" barrel, I will likely replace it with a better brand in a 20" to 22" length, and probably with a profile that's a little closer to an H-BAR DCM.

White Oak makes good barrels & uppers. Same with Compass Lake. Probably more than you want to spend, but I just replaced a shot-out Wilson barrel with a Craddock Precision chambered Bartlein. Haven't shot it yet, but my 'smith was pretty pleased with the barrel when he assembled the upper last week. FWIW, Wilson Combat barrels are quite accurate, especially their super sniper models. Krieger barrels are up their with Bartlein in accuracy, but they are expensive.

It probably won't be an issue, but if you're swapping BCGs between rifles, have someone check the headspace on your varmint upper.

You will want the varmint upper free floated. I recommend a rail with Mlok slots. I am at the start of evolving my handguards to Mlok, with the Craddock upper as the starting point.

What kind of accuracy are you getting with your M400? What accuracy do you expect with the varmint rig?

Given that your Sig M400 works to 300 yards, I suspect you're now looking for a 400-600 yard rifle. Accurate shooting at such distances is a different ball game. You need good technique, consistent loads, good bullets, good wind calls, and accurate dope tables. Whatever scope you choose, make certain the glass is clear, you have a reticle that works for wind & elevation, and turrets that match the reticle. This isn't the place for a BDC-type reticle. Maximum magnification can be anywhere from 15x to 25x. If you must make a tradeoff between zoom power and glass clarity, choose lower magnification with clearer glass.

Great info! Thanks. I'm not wedded to the bull barrel, and was planning on a Wylde chamber.

I have a 20" 1/8 twist with a mid length gas system. Purchased from the former Sabre Defense, this fluted 410 SS is a mid weight Varmint profile. I wish now I had purchased at least one more barrel, accuracy has been a delight. The 8 twist is the way to go, chamber differences have really not been an issue in my AR's. The match prepped handloads do not seem to care.

I am very happy with the RRA Predator Pursuit
https://www.rockriverarms.com/...lay&category_ID=1961

Second vote for the Rock River Predator Pursuit.
I know the thread says “build” but for the money, it’s tough to beat the Predator Pursuit, I love mine !

This message has been edited. Last edited by: GrumpyBiker,

Is it worth paying for a bolt headspaced to your barrel? Looks to be a $100 option from the barrel company I am looking at.

^^^^^^That's probably a good idea. Not a dealbreaker in terms of price by any means, and much more convenient.

Well I went ahead and went for a low mass BCG to be headspaced, adjustable gas block, and even a barrel for my bolt action project. RIP credit card.

Thanks again fritz. There is a ton of information in your post. I am trying to figure out what I want to build, vs what I want to spend. Funny that those things would be in conflict...

I've decided to take your advice on 20 to 22 inches, and go with a match profile, rather than bull barrel. If I don't get anything for the weight, I don't need the weight.

Given my eyes, and 53 years, I don't think that I will be going much beyond 500 yards at the longest. I have astigmatism, and even with good optics, things get funky way out there, and I have trouble discriminating my target.

I am really looking for a rifle with the precision to reward my training. I.e., if I put in the time on technique, practice and load development, the rifle will reward my learning. I am reminded of Townsend Whelen's phrase, "only accurate rifles are interesting" and want to explore what I can do in that arena without spending Lone Star kind of money.

If the best thing I can do is buy a White Oak or Compass Lake upper, that may be the way to go. I could also buy a barrel, and have a local smith mount it to an upper for me, and build my own lower.

As an aside, which is better, a match profile barrel, or a varmint profile barrel? I'm not going to be shooting high volume over a prairie dog field, so the extra weight of the varmint barrel may do me no good.

Thanks for all the help. This is proving to be an interesting project, and will likely cost me more than I had planned...

quote:

Originally posted by ArtieS:
As an aside, which is better, a match profile barrel, or a varmint profile barrel?

Varmint barrels will generally be a thicker & heavier than a match barrel. Probably .1" to .2" larger in diameter at the muzzle for the varmint. The breech diameters may be about the same, but the breech length might be a little longer on the varmint barrel.

IMO the barrel brand and the way the chamber is cut will have more effect on accuracy than the difference between match and varmint contours.

FWIW, I've shot really well in matches with my match contour barrel -- and out to 600 yards, sometimes even 700 yards. But either one will work.

Thank you.

quote:

Originally posted by ArtieS:
Given my eyes, and 53 years, I don't think that I will be going much beyond 500 yards at the longest. I have astigmatism, and even with good optics, things get funky way out there, and I have trouble discriminating my target.

Precision shooting with a 223 AR15 beyond 500 yards is a challenge, but it can be done with a good shooting system. The system includes shooter, barrel, ammo, optics, dope, and understanding atmospheric conditions.

I have poor vision -- horribly near-sighted, a little bit of astigmatism, floaties which continue to become more irritating. I wear progressive prescription glasses, which is the kind term for trifocals.

Do not underestimate the benefit of quality glass in a rifle scope. The benefits occur regardless of target distance or size. Better glass allows for better target identification, better reading of wind effects down range, better spotting of your own bullet's impact, and better resolution of subtle color differences.

This weekend I shot in a precision AR15 match, with targets between 200 and 700 yards on various stages. A bonus stage had one target at 885 yards. There were a few instances where my 4-16x ED-glass scope provided a noticeable advantage over my fellow competitors. The first was stage with 4-to-6 inch diamond targets in six locations from 300 to 400 yards. The steel targets had very little paint on them, and we had variable winds of 4-8 mph from the left. That's enough wind to really mess with accuracy. Spotters with 8x or 10x binos had trouble determining which side of the plates the impacts occurred on, meaning that the best retro-active wind calls were generally made by the shooter. I was able to call my left- or right-side hits with better precision than my spotters.

It's a challenge to accurately see 77-ish grain impacts on partially painted steel at 885 yards. Binos could spot misses in the dirt quite well. Impacts which didn't move the plate very much were more of a challenge. I was able to see my own hits much better than binos -- even Leica and Swaro binos.

https://www.budsgunshop.com/ca...oduct/36004/redirect

Just because you specify varmint shooting, I think the CR6724 deserves a look. 1x9 twist isn't fashionable anymore but fine for varmint bullets. A good rifle, if you aren't married to a build.

Bruce

quote:

Originally posted by RNshooter:
1x9 twist isn't fashionable anymore but fine for varmint bullets.

Fashionable really isn't the word -- faster twist barrels allow bullets which provide greater function.

The 1/9 twist generally limits the shooter to bullets of 69 grains or less. Some 1/9 barrels do OK with 73-77 grain bullets, but generally with longer barrels, higher temperatures, and thinner air. So it's a gamble.

One of the better all-purpose match bullets is the SMK 69, as it works in about a gazillion barrels with twists of 1/9 through 1/7. Its G1 Ballistic Coefficient is .317.

Another great all-purpose match bullet is the Hornady 75 HPBT, as it works in about a gazillion barrels with twists of 1/8 through 1/7. Its G1 B.C. is .395 -- which is a big jump up from .317.

I just retired an 18" 1/7 twist barrel which shot both loads extremely well -- Federal GMM 69 and Hornady 75 BPBT match. From 200 through 500 yards, the Hornady 75 flies with a consistent 10% less wind deflection, and flies 5% flatter to boot. At 100 yards it makes no difference. It takes a good shooter and small targets to see the difference at 200 yards. But from 300 to 500 yards the H-75 loads produce noticeably better flight ballistics, and shooters will hit more small targets with H-75 loads.

I built a fairly precise AR-15 to play in F-Class all the way to 1000 yards. It started life as an Armalite M-15(T) with a 24 inch barrel, but I redid it extensively a year or so into that type of competition.

As fritz so correctly identified, the barrel is the single most critical part of a rifle. If the barrel doesn’t measure up, everything else you do to the rifle will be essentially akin to putting lipstick on a pig.
So, when I decided to get serious and build up a top notch AR-15, I first considered the barrel and elected to bet one from Krieger. Krieger extremely experienced with AR-15s and they offer a number of contours that you can view here:
https://www.kriegerbarrels.com/contours#ar15
The ones to look at are: H-BAR DCM, VARMATCH and VARMATCH-28 IN. I selected the VARMATCH contour because at that time (2006,) they did not offer the VARMATCH-28 IN contour. I chose the VARMATCH in 26 inch length. The twist rate is 1:7.7 and I got Krieger to chamber it in what they now call 223 Long Range. It used to be call NATO Match or some other combination. I sent them my upper with its free-floated hanguard and BCG, and they sent it back to me with the new barrel installed and chambered, ready to drop into my lower.

Currently Krieger offer 3 chambering for .226/5.56: .223Rem, .223 Wylde and 223 Long Range. The latter is essentially the .223 Rem chambering with a longer leade to accommodate long bullets such as the 80JLK, 80Berger, 80SMK and their 90s. The Wylde chamber is a porky 5.56 NATO chambering to facilitate cycling, but with a tight throat for improved precision and a longer leade like the NATO chambers for the long M856 Tracer round.

Understanding that my goal was to compete in F-Class to 1000 yards, I wanted the longer length barrel and the longer leade to accommodate the long 80gr JLK bullet that I wanted to use for that purpose. I accomplished my goal and was able to continue climbing up the NRA rating with that setup until I plateaued and realized that I had essentially reached the limits of the .223 accuracy at 1000 yards in an AR. I switched to a .308 bolt and continued to climb.

I also changed a lot of things in the AR to make it an F-Class competition machine; stock, grip, scope, trigger, BCG carrier weight, etc., but for the purposes of varminting inside 600 yards, the extremes to which I went are not required.

I'm not sure if I saw the answer, but do you handload your ammo? If you are limited to factory ammo, you do not need or want the long leade in your chambering, so a .223 Wylde or whatever is the equivalent at various shops will work just fine for your purposes.

You can view that rifle here: http://img.gg/59sDw9W

Thanks NikonUser for all of this description and info. Beautiful rifle.

I do handload, but am not very experienced at it.

One of the purposes of this rifle is to give me a platform to experiment in that area.

quote:

Originally posted by ArtieS:
I do handload, but am not very experienced at it.
One of the purposes of this rifle is to give me a platform to experiment in that area.

There are many great reasons to handload -- they include getting better performance from your rifle at a lower dollar cost. Go for it, as long as your time allows. Uber-precise accuracy on small paper targets will always lean towards hand loads.

I shoot at steel targets, therefore I don't need bench-rest-type-ludicrous accuracy. Although I admit I'd like it at times. My competition rifles shoot rather well with Hornady's factory ELD-M loads. I won two competitions over the weekend -- AR15 and bolt action -- using factory ammo.

My AR15 did what appeared to be a 1/2" five-round group at 100 yards the last time I sighted it in on paper. Which by the way was last October. The barrel on this AR is 50-60% through its useful life. The rifle held vertical at distance equal to the guys handloading Lake City brass, Varget, and 77 SMK.

The bolt gun produced a .3" group at 100 yards using two different lots of ammo the evening prior to the match, just to confirm that mixing ammo lots in the middle of the match wouldn't be an issue. This gun's barrel is about 75% through its useful life, and I will pull it later this year.

I believe many shooters spend a lot of time and effort chasing tools made of steel, aluminum, brass, glass, and plastic -- but scrimp on the most important tool of all, the nut pulling the trigger.

Get that good barrel, get some reasonable glass, and get some time behind the butt of the gun. These three things will go a long ways to owning an accurate AR.

Excellent treatise from fritz, to which I will only add: do lots of dry firing, especially with an AR-15 trigger, any AR-15 trigger.

quote:

Get that good barrel, get some reasonable glass, and get some time behind the butt of the gun. These three things will go a long ways to owning an accurate AR.

This, by God, is what I am trying to do. I'm not trying to build the most accurate AR ever, I don't have the budget for that. I am trying to build an AR that will challenge, teach and reward me.

I truly appreciate the help and advice you are all so generously providing.

Do you think it is better to buy a built upper, even if that is $750 bucks from someone like White Oak or Compass Lake, or buy components and have it assembled, for a similar cost?