I plan on doing a barrel test at some point, and just got in two I plan on testing:



1. KAC SR-15e3 LPR mod 1 18" barrel

2. Larue Stealth 18" barrel


Both of these are "new" although the KAC was mounted and test fired on an LPR. The Larue may have been test fired as well.

A quick first impressions of the two:

KAC
Contour is much thicker than expected. Measures .980" all the way to the gas block. Barrel extension is a KAC SR-15e3 extension so I will be using the e3 bolt with it. I had originally assumed KAC bought krieger blanks and turned them themselves. However now I'm thinking they may come contoured and extension installed by Krieger and KAC only chambered it. It is advertised as "5R" rifled and while it indeed looks like "5R" style rifling, there are only 4 lands. This is consistent to what Krieger does as they only like to use 4-groove barrels so they can ensure the gas port is centered in a groove. The mark at the 12 o'clock position just in front of the barrel extension is the same as what I've seen with Krieger installed extensions. The chamber looks typical of KAC cut chambers in that it is highly polished and rounded at the entrance.

Larue
The obviously noticeable thing about the Larue is that it's a midlength gas. Many people don't like this and to be honest I'm undecided on it. A rifle length gas should result in a softer shooting rifle, although that can be mitigated somewhat with an adjustable gas block. The advantage in a midlength in an 18" barrel is that the gas port is considerably smaller. As you can imagine, a hole in the middle of your bore can't be beneficial to accuracy and a smaller hole helps mitigate this. The barrel itself looks well made, and the contour seems to be more reasonable for a rifle that will be carried around.

Gas port comparison, note the disparity in size due to gas port location


Unfortunately I don't have a lot of time to shoot due to work now so I can't guarantee when I'll get around to doing my test. I have not decided how I want to go about the test (receivers, lowers, handguards, etc.). The purpose of the test is to see which barrel I want to run on my rifles. The more accurate barrel is not necessarily the one I choose as I need one that is more accurate with the right load(s) since it will be a competition rifle.

Looks good, I can't wait for the test!

If your Larue shoots anything like mine, it'll be a real close competition.

I have the LaRue barrel on a build, it shoots very well.  I will be interested in your results.

To be honest, I'm not terribly impressed with the KAC contour. Too thick without any taper to the gas block. I doubt the Stealth contour gives up much accuracy at all compared to the KAC contour, despite being significantly lighter.

This will be going on an do-all 18" 100-700 yard rifle and unless the KAC blows the Larue away I'm most likely going with the Larue based on weight alone.

I'm interested to see your results.

I'm partial to LaRue, but honestly don't have much experience with many other barrels - mostly because of the value I have found from the LT barrels at the price I've been able to acquire them for.

I'm in on this! I have a Stealth and have shot into the .3MOA range out of my 16" .223. Still getting acquainted with it so hope to see more of that. .5 MOA has been almost easy. Always wanted a Krieger and we all know the performance of those barrels.

Keep us posted!

Can you weigh them and post the results before building them up. 

What's the testing plan?

Whats the twist rate on the Larue?

I bet Krieger makes that for KAC. It's marked just like their own barrels.

AFAIK, they only offer 1:8 twist.  Both of mine are 1:8.

I have not decided yet. I currently have an 18" RECCE build that I planned to shoot in RECCE class of a match series. That is currently running a 18" Douglas but it's pretty much shot out.

So the goal of the test is not necessarily to see which barrel is most accurate, but rather which is best suited for my purpose.

I've pretty much decided on the ammo I will test with:

Geco .223 (accurate enough to practice with and I have thousands)
70 grain RDF over 8208 (three different charge weights)
77 TMK over 8208 (three charge weights)

I may consider a different powder if neither of these like 8208 but I'd rather stick with it if I can due to supply.

I've decided not to test factory match ammo since it is not relevant to what I will be shooting out of the barrel. My handloads are usually much more accurate than factory ammo out of my ARs anyways.

My guess is krieger supplies it to KAC with barrel extension installed and gas port drilled but unchambered.

I'll update with pictures as to why I think so when I get home.

Of course I could always be wrong.

If you are not happy with the results consider a Lilja Recce barrel.  This is the true Navy SEAL recon barrel made by Lilja for Navy Crane:  True Recce profile, 416 stainless, 1:8 twist, Wylde chamber, pull button rifled and hand lapped.  It will do 1/2 MOA or better, if you can.  Nominal 16" but measures closer to 17".

Either one of the barrels should be accurate enough for the purpose. This is not going on a dedicated precision gun, but rather a general purpose rifle with a 1-4 optic mounted.

Lilja is known to make excellent barrels and I tried them out a couple years ago. The barrel performed poorly due to the extension being attached non-concentric to the bore. After much back and forth and skepticism, CS took the barrel back but wouldn't take the matched bolt that I also purchased from them. While I would try a lilja barrel again, that overall experience left a bad enough taste in my mouth for me to not consider them a first choice.

Bit off topic here but they allow 18" barrels in a RECCE match? Thought RECCE was a 16" match barrel?

You are correct, they used "RECCE" in name only just to represent 3-gun rifles, many of which are 18". The rules are that the rifles are limited to 6x magnification and not allowed a bipod. DMR class has the same course of fire but does not have those restrictions.

Subscribed and awaiting results.

Something not mentioned thus far, and important to a cheapskate such as myself, is the cost disparity between these two barrels.  The LaRue is $225 and the KAC I'll guess at $400+.  I have a Centurion (I think I paid $360 new for it, but typically $425+) and a LaRue and yes, the Centurion shoots better, but only by a very slim margin.  Once cost enters the equation the LaRue is very tough to beat.  

One thing about the LaRue though is that I had to deburr some sharp edges on the feedramp and barrel extension.

I may have to invite myself to your place to do the test. Easier to install and remove barrels if I decide to do it on same upper.

Also do you have a scale suitable to weigh these?

Yes, have suitable scales and am willing to help with my range.  Very curious about this test myself so I'd love to help.

Feedback like this is probably why KAC went with a lighter contour on the MOD 2 LPRs. Word is that it does not give up much for precision but handles much better. Their reps in the industry forum are very forthcoming with capabilities, materials and design considerations if you cared to ask.

Very interested to see how this turns out, but it is worth noting that the KAC LPR barrels are not generally available for separate purchase. It should, however, be a decent Krieger vs LaRue test.

Also very interested to see how the RDFs shoot for you. BC looks great and they are cheaper than TMKs...

Finally, has anyone figured out what Rearden Steel is? I get the Ayn Rand reference, but am more interested in type of stainless.

Yes, I have heard the same thing about the Mod 2s. Combined with the fact that the URX4 is lighter than the URX3.1 and the LPR mod 2 looks very appealing.

So far I have not had luck with RDF 70 grain bullets. I have tried it in my DMR (20" Krieger 7.7 twist) with no luck. Multiple loads and seating depths. A friend had similar results with his Shilen barrel, but since I have bullets available so might as well.

Not sure if this is a valid Krieger vs Larue test unless we confirm that Krieger did the chambering. I am of the opinion that the quality of the chamber is just as important if not more so than the maker of the blank.

No date as of yet, work has been crazy.

Good point. I am not sure if Krieger is making the Mod 2 LPR barrels. Either way, MOD 2 LPR would be on my short list if I needed a light 5.56 precision gun.

Too bad the RDFs aren't working. Loaded up some 77gr TMKs over TAC and 8208 last night to test in a couple weeks.

Berger's 70 grain VLD is comparable to the 70 RDF.  The VLD is very sensitive to seating depth for magazine cycling. I got lucky and found that mine shoots well at  max OAL of 2.260" from my 1:8 twist Lilja 16.  That long tapered shape back to the case neck may be a challenge with the RDF, too, and might explain the performance issue.

It'll be a nice shootout and am interested in the results.  I did one for myself against my 18" Odin Works vs. my 20" LaRue.  With the 80gr Nosler's the Odin Works was a 0.97 moa for 5, 5 shot groups.  The LaRue was 0.49 moa.  The LaRue has a MBT 2S trigger, the Odin Works a stock trigger.  Big difference in trigger pulls and not a fair test, but I replaced the trigger in the Odin Works to an MBT also.  When I get back from vacation, I'm gonna re-do the test between the two.

I picked up a bunch of 70gr RDF blems, and in my testing, I was able to find a node at mag length.  I also loaded some up .106 longer and single fed them and found a good load also.  I shot 15, 5 shot groups and 6 of them were sub moa at 100yrds.  The targets shown were the best of them.  Was shooting these out of a 20" Stealth barrel.  I duplicated the 24.0gr at both lengths to re-test, and loaded some at 23.9 & 24.1.  Hoping I can fine tune them some more.  I single feed 80gr Nosler's out of this rifle, so I don't mind if they're longer.  The node is there, you just have to find it.

I was using Win 748, LC brass and CCI400 on the targets shown.


Attached File

I was able to get some weights today, thanks to blazin.





The Larue barrel came out heavier than expected. I was under the impression that it was a lighter contour than an 18" SPR contour. The KAC was obviously much heavier.

We also took some measurements of the barrel extensions:





The KAC's extension measured from .997"-.999". We noticed the diameter varied quickly jumping from high to low points often.





The Larue's extension measured from .997" -.998" and transitioned smoothly.

The the lugs in KAC extension were very smooth with no sharp edges at all. Having rounded lugs probably helps. The Larue extension "looked" very sharp next to the KAC, but really wasn't too bad at all. They felt just fine when feeling with a finger. I have felt other brands (BCM) that felt like they needed filing immediately.

Looking to do this test soon. It may take a little more effort to do quickly since the KAC barrel has a pinned gas block.

Does anyone have a spare BCM barrel nut I can borrow? I'm hoping someone upgraded theirs to the V7 titanium and has a regular one lying around.

It would be much easier to just change out the assembly as opposed to worrying about the gas blocks.

In for the results

Not impressed with SR25 accuracy.  Done better with Larue OBR and LWRC REPR.  Like to see what these tests prove.

Like anything else seems to vary gun to gun. Some are hammers some are lightning. Had an SR25 that was more precise than one of my OBRs and pretty much on par with the better one. Oddly the OBR that came with a nearly .9xx" test target is the most precise of them all.

As applies to this barrel shootout it is a tube krieger made for KAC...I believe all the SR25s use obermeyer or in-house barrels.

Sorry guys, been crazy busy with work and match schedule. I have one upper assembled, but waiting on parts for the other. I ended up putting the KAC in the existing rifle and bought an Aero M4e1 for the Larue. That will most likely turn into a budget precision build that I'll build as a demonstrator and likely sell.

Update: I had to deviate from my original plans.

The Douglas barrel on my rifle bit the dust over a very short period of time, and I needed to replace it quickly as it is my loaner rifle for matches and I had several people interested in shooting them. I choose to go with the Krieger, mainly because I misplaced the Larue and couldn't find it.

In any case, since the Krieger had a pinned gas block and was a colossal PITA to install, I abandoned my plans to run both barrels on the same upper and just do a barrel swap at the range. I instead built a second upper for the Larue barrel (that I eventually found) to conduct the test. I also decided to use this opportunity to try out the Aero M4E1 upper as I am always a fan of handguards that attach directly to the upper instead of barrel nut for a precision application.

Unfortunately for whatever reason, the Aero M4E1 upper was too tight on my Aero Ambi lower of my 3-gun rifle, so I had to borrow a LWRC lower for it to make a complete rifle. Here are the two rifles to be used for the test:


They are a little different, and it may not be a fair comparison since one is set up for pure accuracy and the other one isn't.

Rifle 1 (KAC Barrel):
Aero Upper/Lower
BCM KMR (original, not Alpha)
Larue MBT
Young's SLC carrier, KAC e3 bolt
Standard assembly
KAC Barrel with approximately 300 rounds

Rifle 2 (Larue Barrel)
LWRC Lower
Aero M4E1 Upper
Larue MBT
KAC Bolt Carrier, Larue Bolt
Barrel bedded into receiver via Rocksett
Larue barrel with 0 round count

Rifle 2 is built more for precision as I feel the M4E1 is advantageous in regards to precision since the handguard does not touch the barrel nut. The Larue barrel has also been bedded into receiver via Rocksett. I previously used the method very successfully on my DMR. However, the KAC barrel has had a few hundred rounds to settle in, and is more accurate now than the first time I took it to the range.

I was hoping to use the same optic to test these, but since I don't have a 34mm QD mount, but have standard mounts and will be playing optics musical chairs in the near future, I might as well use what I have. Rifle 1 will be tested with a 4.5-27X56 Vortex Gen II Razor on a Geissele mount. Rifle 2 will be tested with a Steiner M5xi 5-25X56 on a Spuhr mount. I know for consistency's sake I should use the same optic, but since I've already blown consistency out of the water I might as well do what's convenient. Both of these optics have a good enough track record so I'm not worried about them holding zero.

Lastly, since I'm testing these two rifles anyways, I might as well compare it with my DMR:



This rifle is currently #5 on the MOA challenge (and did so with a load development target) and is last year's winner of the PASASS Series. While it's not as accurate as it used to be from throat erosion, it will still be a decent benchmark to compare the two builds to.

How a mess is your gun room that you lose a barrel?

It's pretty bad. The good news is that when I was looking for the barrel, I found a case of 77gr ammo that I forgot about.

I find cases of ammo all the time...

Now that I think about it, rifle 2 is a perfect example of "budget precision", which is asked about a lot on this forum. The price breakdown:

Larue Stealth barrel(M4 cuts): $245
Aero M4E1 and quantum handguard: $160
BCG (user choice): $100
Gas block/tube: $40
Charge handle(BCM): $40

So something just shy of $600 gets an upper that I expect to be able to run with the best. I don't think the accuracy of this upper will be limited by individual parts but rather the nature of a semi-auto.

I just need the time to get out and shoot.

Looking forward to the results!

I have taken them out a few times but have held off on posting results because of what I am deeming an anomaly.

I have built several rifles for other people using larue barrels and they shot very well. This one however seems to be an exception. At the moment I am working on testing a known good shooting Larue barrel in my Aero M4E1 upper to make sure it wasn't an issue with the build.

The KAC barrel has been very impressive. Sub-MOA 10 shot groups with 55grain FMJ impressive.

Well Don't chase your tail with a LaRue barrel that won't shoot..... It's more than likely the barrel.  (Yes I know they have a reputation for accurate barrels)
A year or so ago I decided to ordered two LaRue Stealth barrels and come to find out, neither shot worth a shit!!
Like you, I have built over probably 15 precision Ar-15 or Ar-10 platforms in the last 15 years (all with Krieger,
Shilen, Noveske, Rock 5R, Bartlein, Douglas, Obeymer, Saturn, Ect Ect.) I've been shooting Precision Bolt/Gas guns since 2001 and I torque everything to proper specs, I square the receivers and use the best equipment and LaRue was the worst out of all of those barrels.
I tried at least 7-8 different Match grade ammunition with different bullet weights and nothing under 1.25 MOA and so I took my old Noveske barrel I took off of my rifle and the Noveske shot under 3/4 MOA rapid fire like it always has.
I sent the two barrels back to LaRue and they tried to call to tell me that both barrels shot UNDER an average of .60 MOA on a 5x5 target. I asked when they shot the groups and the guy told me that he shot them and then proceeded to call me right after shooting the 5x5 target so I asked him to send the targets back with the barrels and you guessed it..... no targets were sent back!!
So I ordered a Compass Lake Krieger that replaced the LaRue barrel and I will be going out in the next few days to shoot that one for accuracy.

I honestly believe the $200 Stealth barrels were reject barrels that didn't make the cut on their full rifle builds and that's why LaRue blew them out.

Is this one of the "in house" made Larue barrels? Or an older one that I believe Lothar made for them? I have a $220 Stealth barrel as mentioned above and it's just as accurate as my other best barrel (WOA). It shot a 5/8" group (5 shot) at 100 yards. Good enough for me.

One of the in house ones. One of the first when they started with the $200 sale.

Interesting. I think they may have had some teething issues to overcome when they stood up in-house production during the "get a field grade now, rebarrel later" era.

The LW50 barrels were very good. I hope the LaRue-made units since they have sorted things out are as good.

The xtraxn is a little bit of a turnoff, however. I find that brass sizes pretty hard after going through it.

My larue made barrel printed a .376" group @100 yards last time I shot for groups, they're gtg in my book, not sure about the other guys experience.