I threw this one together recently.  When I grab the soft case with it inside, it feels empty.  The thing is light.  I could go even lighter, but it's really well-balanced as is.  Handles smoothly, especially with the Phalanx carrier and JP SCS.  7.75lbs with scope and mount

Upper Receiver Group

Lilja 17.625" Wasp barrel with SAAMI chamber cut by AA, AA barrel extension, blended and polished by me (gas port diameter is .076")
Precision Firearms/Maxim Grendel bolt, 9130, with ejector radiused and phosphated by me
Precision Firearms Black Nitrided full weight bolt carrier (very smooth, beautifully made)

Aero Precision no Malfunction Assist Forward upper receiver, FDE Cerakoted
BCM Gunfighter Charge Handle
Sadlak lo-profile gas block, indexes off the barrel shoulder, Red Loc-tite'd
Custom gas system length gas tube made by AA for this barrel
Precision Firearms black nitride flash hider, with helical slots, 5/8x24

Midwest Industries Gen II SS Handguard, FDE anodized, and FDE Cerakoted

Lower Receiver Group
PSA lower FDE Cerakoted, color filled
Tuned RRA 2-Stage Trigger
JP Silent Captured Spring
M4 Receiver Extension Tube, FDE Cerakote
Magpul MOE+ (elastomer covered polymer, feels like rubber)
VLTOR Clubfoot FDE stock

Sighting System
Vortex Viper PST 2.5-10x32 MRAD w/zero stop, SF, Front Focal, Illuminated
NigthForce Unimount 20 MOA one-piece base, ring screws tightened to 18 inch pounds, base screws to 65 inch pounds
Bubble level Shoe Goo'd to back of scope base




Top Right:  .223 Wylde M4A1 Block 2 SOPMOD Clone, Middle: New Grendel, Bottom:  16" Grendel

Cool

Nice! Sounds and looks awesome.

more info on the gas system?

That thing is slick! What does it weigh with optic?

I had it short chambered and a new barrel extension timed to the gas port.  That required a custom gas tube length that is .6" shorter than a MLGS.  I would prefer a little longer than MLGS actually on an 18" barrel.

This one has a .076" port diameter, but the gas system length and dwell time indicated to me I was going to need heavy buffering and springing, so I wanted to see how the JP SCS would tame it.

Ejection was 2:30, which is a little more forward than I would like, indicating a bit of a fast cyclic rate, but still reliable.  Temp was 50 F.

I'm considering taming the gas a little with some other methods, not including an adjustable gas block though.  It does work as is, but we generally like to see 3:30 ejection.

Weight of the complete set-up is 7.75lbs with 2.5-10x32 Vortex and NF Unimount.

Without scope, it's 6lbs 2oz.

How do you like the PST 2.5-10? That's the optic I'm eyeing to put on my Grendel to replace this Leupold 4-12 which has awful eye relief.

I almost forgot about this barrel. How did she end up shooting?

At 100yds with 123gr SST factory load, it appeared to be around 1 MOA, but the targets got pulled down before I could measure them up close, so I just went off what I saw in the spotting scope.

At 470yds, I printed a group on steel that was basically rounds impacting on top of each other.  You could see the same splash on impact on top of impact, and I could spot my own hits since it's so pleasant to shoot.  

It's a very lightweight set-up, so it wants to get squirrely on you, but it makes an awesome little hunting/target rig.

I was also able to get hits at 1045yds on a 22" steel plate with it.  I'll work up a better load than the factory fodder with the 123gr and CFE223.

For comparison, I jumped on my .260 Remington gas gun, which is literally twice the weight, and I could not spot my hits due to the recoil, some primers were flattened and cratered, while others were dimpled.  I was pushing the 129gr SST at 2750-2800fps on top of a load of H4350.  My jaw was hurting from the .260 Rem initial recoil impulse as well, to the point I didn't want to shoot it anymore.

The charge handle clearance on the AR10 is such that we can't put the cheek piece where it needs to be, so you end up with odd residual muscle input that takes a beating from the recoil, at least I do.  I need to do some tuning on the .260 Rem to get it to run smoothly so that I can spot my own hits without an offensive muzzle break.  I'll probably drop in a JP AR10 SCS.

Another thing with the .260 Rem is that I really need to uniform my necks, or else the ES is all over the place, and my case length stretches considerably with each shot because of the pressure.  There is a lot of work at the bench required to keep a gas gun fed if it runs on high pressure, and you hand load for it.  No way can I run factory through it, so there's my options.

With the Grendel, none of those issues are there, and every single factory load specifically works in the AR15's gas system.

Just got back from the range with it.  Temp was around 22 F, with wind on top of that.  Fingers were getting frozen.  This gun is going to bughole when I hand load for it, I can feel it.  It's shooting extremely well for a lightweight barrel of .650" under the handguard, and .740" at the fore end, with a .750" gas block journal.

This is one I sent to AA to have it chambered.  Bill A. said the bore was the probably the best he has seen in terms of smoothness.  Lilja didn't earn their reputation by accident.  I'm really enjoying this carbine.  Even with the 2.5-10x32 Vortex, bipod, and mag, it's 8 lbs 12 oz., and I can spot my own hits with no muzzle break, partially thanks to the JP SCS recoil spring and buffer system.

Receiver face is square.

Barrel is bedded with Blue Loc-tite.

Precision Firearms flash hider is symmetrical.

wow.  awesomeness there sir....

That's awesome man! I do believe you need a 11.5" Lilja SBR Grendel to go along with that bad boy. HAHA

What I was going for here were 3 things that often contradict each other:

* Lightweight

* Exceptionally accurate

* Semi-auto

JP has been defying these combinations for years, cranking out very well-balanced, highly accurate, semi-auto rifles that pattern 10rds into an inch at 100yds consistently.

I wanted a lightweight intermediate target stick, that also makes a great hunting carbine with substantial retained energy.  Several companies came together to make this project happen.

* Lilja Rifle Barrels
* Alexander Arms-did the reaming
* Precision Firearms-Phalanx Bolt Carrier Group Black Nitrided, tuned tool steel Grendel extractor, Beautiful symmetrical flash hider
* Aero Precision Upper with square face-came that way
* NightForce Unimount
* Vortex Viper PST
* Wheeler FAT Wrench, for balancing the load on all fasteners for the optics mount

I'm gonna ask.even though I shouldnt...what does a project like this cost to do?

I bet he's sneaking up on 3k with scope

The only parts that really are above average costs are:

Lilja barrel.  This is one of the group buy barrels we did, so I got it for less than normal.  I got several of them through the group buy since I knew it was a rare opportunity at the time.  Lilja has since made 6.5 Grendel barrels a normal product line, and I recommend them highly. I think they are $450 from Lilja, without fluting.  The fluted barrels look awesome.

JP SCS recoil & buffer system.  $127

I got a great deal on the PST from Liberty Optics in Montana.  Way less than MSRP.

NightForce Unimount was over $200, but it's one of the best one-piece bases I've ever owned, and is at a nice height for my cheek weld to eye height.

Precision Firearms Phalanx Black Nitride BCG is $185, with a tuned tool steel extractor as a standard feature.  Bolt is 9130 AQ.

The Aero Precision upper is pretty cheap, nothing special.  I Cerakote'd it myself. $90

Ejection port cover assy:  $12

BCM Gunfighter CH:  $45

The lower is just PSA $49.95 blem, Cerakote'd again by me.

Handguard is MI Gen2 SS, Cerakote'd, maybe $160

Tuned RRA 2-stage was given to me.  I'm going to replace it, since I prefer single stage JP with the speed hammer.

Sadlak gas block, $22

PF flash hider:  $50

LPK (-):  $30

Magpul MOE + :  $19

Vltor Clubfoot, BCM special sale way back:  $50

Mags are $13-$14 a piece.

So we're looking at $1225 for the fire stick, not counting the free trigger.  About $900 for the scope and mount together.  I distributed the costs over a long period of time, so it wasn't all at once.  I have a lot in bench tools and AR15 specific parts already, so this felt more like throwing things together.  A lot of the work involves little tweaks to make the gun shoot and run well.  Radiused ejector, phosphated after material removal, feed ramps blended and polished, infrastructure to do metal prep work, airbrush, and bake on H-Series Cerakote.

Depending on what components you use, you could spend $1200, or $2400 on the rifle itself similarly configured.  It's a buyer's market still for a little while more, especially on common parts.  A BALIOS-Lite receiver set would have been really nice, but would have cost $340 more.

There was probably $100 additional in FFL and shipping fees for everything.  I think it's all worth it when you consider that this thing will reach out, shoots like it does, and is very lightweight.

wow,thats not nearly as much as it would seem.gunsmiths by me are like dentist,cant leave without dropping 350!

I could have cut costs by using an H2 or H3 buffer and standard recoil spring, but there's something about being able to spot my own hits without a muzzle break, while still having 85% of the energy of a .308 at 100yds, and 91% of .308 at 300yds, from a rifle that weighs 7.75lbs with optics that are just a bit large for hunting, and a nice balance point to the rear.

When you cleanly break the trigger, and watch round after round going in the same place, you get a certain affection for a rifle.

I like it a lot.  It's probably one of the top 2 scopes right now for bang for buck, with the features I like.

I bore-sighted it by leveling the upper, then leveling the scope, FAT Wrenched the screws to equal torque spec, then Shoe Goo'd the scope level in place.  It's right at the rear of the NF Unimount, and can be seen easily when in position.

My 16" Grendel has the earlier 2.5-10x44 MRAD PST, and I like that scope as well.  There is supposed to be a big difference in the glass, but I'm one of those people whose eyes adjust immediately to most optics, so I have a hard time seeing much difference.  Hensoldt?  Sure, I'll notice the difference, but not much with these.  I would have to side-by-side them.

Always enjoy reading your Grendel posts.  Very detailed and good stuff.

Looks like a great rifle.  Some questions for you…

Is there a noticeable performance gain over your 16" in the same configuration?  Weight, velocity gain, accuracy, etc.?  Curious why you didn't go with a 16" in the same barrel profile.
Does the thin barrel's spread widen considerably when hot?
Could describe more of the cheek weld issue you experience when shooting your .260 Rem?  I'm curious to understand this better.

Thanks

This one seemed to shoot better the more I shot it, but that's probably more to do with me getting settled into the gun.

I haven't chrono'd it yet.  I'm going to run my CFE223 /123gr ladder test batch protocol through it, and see what it likes.

On the AR10, you can't have the adjustable cheek piece too close to the receiver, because the charge handle needs enough room to retract to the rear.  The AR10 CH is a lot longer than an AR15.  I guess I could move my scope back a notch, but I like a bit of clearance from the ocular bell and the CH, so it isn't in the way, even with the Gunfighter Charge handles.

I'll probably drop a JP AR10 SCS in my .260 Rem to see if I can tame the muzzle climb that way.  I don't want a brake on it.

I'm building a Grendel now, and am very interested in that barrel. How exactly does that work? You ordered a blank from Lilja and sent it to straight to AA? Lilja doesn't chamber in Grendel, or do they not have the correct spec reamer?

Why the hell do barrel companies turn the barrels to a smaller diameter near the chamber, then increase it after the gas port?

Lilja makes drop-in 6.5 Grendel barrels with the SAAMI chamber.

This one was from a group buy we did through the Grendel Forum.  It had a different chamber in it, so I had it short-chambered, a new extension installed, and a custom gas tube made for the slightly shorter gas port location.

The M16A2 had a pencil barrel, then gets larger at the gas block and fore end.  Lilja calls it a Wasp profile.

JP also does it on most of their AR15 and AR10 barrels.  Makes for a great handling barrel that resists whip well if the steel is high quality.

How does the lija barrel compare to the JP barrels in accuracy? Iam also looking into a grendel . Iam torn between it and the 6.5 cm. One thing i like about the grendel is ,i could always put another 556 upper or blkout upper on it.The farthest I shoot is 600 yards.I may get to try 1000 one of these days.

Thats a very nice rifle.

To buy a jp or build will be my other problem.

I would say the accuracy is very comparable between the Lilja and JP, to the point that you will have to look at individual barrels, rather than the source.

If most of your shooting is at 600yds, then I wouldn't even mess with the 6.5CM unless you're actively competing and can afford the time to load for it.  Factory ammo poses a lot of problems for most 6.5-08 type cartridges in the AR10.  

JP makes very solid rifles, that feel like one piece, and are well-balanced.

Lilja makes 4 different profiles 24", 20" I believe it's a heavier contour,  2 18.8" one in wasp and the other heavier.

Thank You!

Out of curiosity, why did you choose the AA SAAMI chamber instead of one that allows for a longer COAL?

Because the one that allows for a longer COL is way too long for the magazine, and is poorly devised, but makes sense for people who want to run a reamer as long as raggedly possible, rather than have standards for their tooling.

The other reason is that the SAAMI reamer is a known performer, and I have seen it work well across a wide range of projectile shapes and weights on many different guns.

For example, on my original 16" Grendel, where I bought an AA Barrel/Bolt combo from Midway back in 2009, and built my own set-up, no matter what bullet I have tried, it averages 1 MOA.

90gr TNT
100gr NBT
107gr SMK
120gr SMK
123gr Scenar
123gr A-MAX
123gr SST
129gr SST

It's boringly predictable that it will just shoot, and I load those to 2.245 or longer, while still fitting within the magazine restrictions of the AR15.  And that's with an ER Shaw button-rifled barrel.

Whoever thought it was a good idea to make a chamber that creates insane amounts of jump might make Roy Weatherby blush, but in this case, it's a really bad idea, unless you single load over a lead sled that won't fit in the magwell with the projectile hanging off the edge of the magazine.

When looking at other rifles with the SAAMI chamber, I have seen 8rd groups in the teens at 100yds, and personally shot the rifles on steel at 700yds with an IPSC flagger (have to hit the center disk to make the flag fly out), that it was predictably boring.

I really shoot 123gr almost exclusively for my personal use, but also do a lot of load development with other bullets for work on the reloading handbooks, so it's nice to have the versatility of the Grendel chamber.  If I was only shooting 123gr, the .264 LBC-AR chamber would be plenty fine, although the neck is slightly tighter, and needs to be monitored a little more closely for reliability, which brings up another important point.

My Grendel's just work.  They eat everything I have fed them, to include that 123gr PPU soft point ammo, both Hornady Factory loads, AA 123gr Scenar loads, Precision Firearms 123gr Scenar loads, and all my hand loads, starting with weak minimum loads, to max loads.  The gas system works, feeding and extraction have been uneventful.  Guns just work.

I'm not going to try to fix that.

Just what I was looking for! Thanks a lot for the response.

Here's the rifle in question put to use in my Winter DM Course this past weekend.  Didn't skip a beat, very low-maintenance after being subjected to some pretty harsh conditions, high humidity, freezing precipitation, temp drops at night, high of 40* F.  This has been a great performer so far.  I'll continue to take it through the paces.

Bitchin

Knowing what you know now, what would you change about the build, if you could go back and do it again?

I grabbed a lower I had already on one of my .223 Wylde DM carbines, which has a RRA 2-Stage trigger in it.  That trigger has to go and will be replaced by a JP single stage.

I would have also Cerakoted the barrel FDE before building the upper.  I wasn't sure what I was going to do color-wise, so I left it stainless.

The critical core components of the gun are sound though, namely the barrel, bolt, bolt carrier, and JP SCS recoil system.  The gas system is sealed and aligned with the carrier key well.

It's very accurate, and it runs 100% so far including 123gr A-MAX, 123gr SST, hand loads, PF 120gr Scenar-L, PPU 120gr MPT, and 100gr Steel Case.

I'm going to probably put a Magpul MLOK low profile QD sling socket on the handguard.  In hindsight, I would maybe get the Keymod MI SS handguard since it has QD sockets all over up front.  I would also consider a carbon fiber handguard, which was my original intent.

I'm very happy with how it weighs and how it performs though.  It is striking how light it is when people handle it, even with optics and bipod.  I would put the smaller 6-9' Harris on it versus the 9-13". I have a 6-9" on my 16" Grendel right now.  I'm going to Cerakote my bipods, as they can accumulate a lot of moisture in places that are difficult to reach.

LRRPF52

Thanks for all your posts and sharing the vast amount of knowledge you have. I really appreciate...

I can't wait to build my grendel.

My pleasure gents.  There were 2 guys who attended this course and brought 18" 6.5 Grendel's.  When they felt this Lightweight Lilja build, they immediately commented, "Man, that thing is light."

The Grendel hits steel with much more authority than 77gr 5.56 load all day long, yet the handling is not that different.

These guys brought a lot of 120gr PPU MPT and the new steel case load for closer distance practice.  The 120gr MPT from PPU was impacting higher than the ACOG BDC calibrated for 7.62 NATO by 1.5 Mils at 600yds, with confirmed zeros at 100yds.

Great looking build. I enjoy 6.5G immensely as it is very easy to load accurately. So far I have found Lapua brass and 123gr Scenars to be the most accurate in my rifle.

Quick question for you. I have a Satern barrel that was made around 2011-2012 time frame. Would you by chance happen to know what type of reamer Satern was using then?