10 years with the 17.6” Lilja Grendel

[LRRPF52]

I just realized it has been 10 years since I put together the 17.6” Lilja from the first forum group buy. It’s a unique Wasp contour barrel that is really lightweight, but has been repeatedly-accurate and quite precise for such a light AR-15. It has also been boringly-reliable after many range trips, shooting courses, and load-testing sessions over these years.





The main ammo I have fed this carbine is hand loads of 31.2gr of CFE223 under 123gr A-MAXs, as well as Hornady 123gr ELD-M factory ammo.

I basically shot this blaster from 2014-2017 almost exclusively for anything LR until I built the 12” Grendel. I shot some 16”, 22”, 20”, and 18” as well, but really focused on that 17.6 Lilja until I did the 12”, then have mainly focused on the 12”. I usually take them both though.




Since last year, I’ve been having my youngest son shoot it to get him trained-up and shooting steel at distance.





He has shot it at 300yds, 400yds, and 1000yds so far with a very high hit rate. I think he only had 1 miss at 1000yds out of 4 or 5 rounds of the new 100gr ELD-VT.

6.5 Grendel 17.6” Lilja

Lilja 17.6” Wasp contour barrel with MLGS, .076” gas port, bedded into the upper
Precision Firearms Flash Hider
Maxim/Precision Firearms Grendel bolt
Standard bolt carrier (later replaced with Bootleg adjustable gas carrier)
M4 with No Forward Assist upper, Cerakote FDE by me
Midwest Industries Free Float handguard with 12 o’clock continuous rail, FDE
BCM Gunfighter Charge Handle

Old School PSA A2 forged lower, Cerakote FDE
Geissele SSA, then LaRue MBT-2S trigger
SPR or Magpul MOE+ grip
VLTOR Clubfoot or LaRue RAT stock
Carbine RET, Cerakote FDE
Carbine spring
Carbine buffer

NightForce Unimount 20 MOA
Vortex Viper PST 2.5-10x32 the whole time, still tracking, dead-on at 100 to 600yds.

It has been just a great little lightweight carbine that shoots more like a heavy bolt gun on-target.

Things I would do differently (nit-pics):

I would use an ADM UIC Ambi billet lower receiver or cut a PDQ lever channel into the A2 before I Cerakoted it.
I maybe would have spec’d the gas system to Intermediate Length and had PF do the work on the barrel with their ILGS set-up.
I would have gone with the LaRue RAT stock out of the gate maybe with the bag rider attachment from LaRue.
I would have preferred a handguard with a small 6 o’clock section of rail for a QD bipod option.
I would have painted the scope and mount.
Maybe texture the SPR grip and Cerakote it FDE.
I would have Cerakoted the barrel FDE.

[Timitus]

It's a great feeling when something you put together ends up so reliable and still so useful after all the new gear that showed up in the safe.

[Timitus]

What would you say is the round count through that barrel now?

[LRRPF52]

I was just trying to figure that out myself. I failed to keep a round count log.

The various load development work alone is substantial though, aside from my go-to volume shooting.

I used it in events and courses at least 6-8 times per year from 2014-2019, not counting any zero confirmation, load development, or campouts. Since 2020, I would say it goes out 2-4 times per year, and picked-up over the last year since I put my kid on it.

I’m guessing 5,000-7,000rds.

I put a lot of Precision Firearms 123gr Scenars and 123gr SMKs through it, as well as 120gr Scenar-Ls that come in the 50rd boxes.

Shot a lot of 123gr A-MAX and 123gr SST until the 123gr ELD-M came out.

When Hornady had the 200rd ammo cans of 123gr American Gunner, I packed my shopping cart full to the point that my little guy got evicted from the child seat, and the bottom rack of the cart was packed too. I miss $139.99/200 days for Hornady. Sportsman’s had a grand opening and Black Friday event with crazy deals that day in 2017.




I don’t have any of that left. Great ammo that has high hit probability at distance.

I’ve also shot a lot of 120gr Federal OTM through it, as well as some 110gr PPU. For my hand-loads, I typically loaded 100-300x 123gr A-MAXs before any course or event.




Even with that round count, it’s shooting like it did out of the gate.

The only reason I’m posting this stuff is for people that are looking to roughly duplicate it for themselves if they want a formula.

I did de-edge, blend, and polish the feed ramps, chamfered the ejector, made sure the extractor didn’t have any sharp corners, bedded the barrel, and bedded the gas block and tube. I used low torque on the muzzle device per suggestions from AMU.

This one has a real SAAMI chamber cut by Bill Alexander. The original chamber was done with another reamer spec that we didn’t bless-off on, so I sent it to Bill and he short-chambered and re-indexed the gas port TDC for me, cut a special gas tube length for it since it’s actually maybe .625” short of a MLGS, hence the 17.6” and not 18”+ barrel it was originally.

[LRRPF52]

One thing I love about this carbine is that it still shoots like it did the first day I grouped it.

On our last range trip a few weeks ago, I made a 1st-round hit with it on a steel plate at 600yds in 4-16mph wind that was erratically gusting from left-to-right. The range flags down at 600yds were stood up about 75%.

I pulled out a magazine that had some of my 123gr A-MAX on 31.2gr of CFE223 hand loads, inserted it, and 1st-round connected centerline and near-center of the plate.

This fire stick just hits what I want with such confidence, while also being very lightweight. That was what I was aiming for with the build.

I knew I could have gone with a really heavy barrel, but after experiencing superb results with a SAKO 75 Featherweight .308 dropped into a McMillan and suppressed in Finland, I knew that some steels and barrel-makers can actually make a lighter pipe that will hold up to shooting sessions common in Long Range multi-day courses, and rolled the dice with Lilja, hitting 6s.

Here’s a 2016 photo of how it shot before I even installed the LaRue trigger:

100yds


1000yds rapid group of 6rds:


With Hornady 123gr ELD-M, it still groups 5rds into .8" to .9” at 100yds.


Brass ejects looking like this:



I normally don’t even mess around at 100yds unless confirming zero. I prefer to just shoot it at distance from 400-1000yds. It will be the main dial-based turret/reticle scope for the kids to learn on for long range work.

[LRRPF52]

Another thing I wanted to point out is that the only scope and mount I have ever put on it is what you see:

Vortex Viper PST 2.5-10x32
NightForce Unimount 20 MOA

That scope has held zero, tracked back and forth through endless rotations for elevation changes ranging from 100-1000yds across a wide range of environmental extremes. Every time I dial it to the indicated dope from my ballistics program, I’m center-punching steel with the 123gr A-MAX and ELD-M loads. It has the old school shim zero stop in it, which has worked fine for me all these years.

It has been used in everything from hot/dry/high altitude to below-freezing, windy, and snow storms:

[Okie_Poke]

Thanks for sharing all of this.

[LRRPF52]

Someone asked if I chronorgraphed the 100gr ELD-VT yet, which I have shot a bit out of this 17.6” Grendel. Some very interesting findings have come up.

I didn’t chrono it, so I took the box data of 2730fps from a 24”, plugged it into a Grendel internal ballistics engine, and got 2598fps for my 17.6”.

I used that and plugged it into my program, 1st-round connect at 700yds, dialed to 800yds, connect, went to 1000yds where we finished out water-lining it. Initial drop prediction for 1000yds was low and right on the target, so I adjusted up to centerline with the group, which ended up being 10.8 mils. It was pretty cold at about 20˚F if I remember correctly.

Truing it with Hornady’s program to 10.8 mils at 1000yds in the conditions I was in, it’s showing a mv of 2590fps from the 17.6” barrel. I just looked at 6mm ARC in that weight and this is basically duplicating or exceeding it. If you shot the 103gr ELD-X 6mm from ARC from an 18” at 2575fps, it has more drop and drift than what I’m seeing from the 100gr ELD-VT 6.5mm at 2590fps. You have to go to the 110gr A-TIP to get below the drift it seems. 108gr ELD-M didn’t do it when I ran it through the 4DOF Doppler program.

Weird. So this 100gr ELD-VT is like 6mm ARC performance without needing to make the switch. I just double-checked that I entered in all the same variables for the conditions, and I’m using real-world drop and impact data that I recorded from the 17.6” Grendel shooting factory Hornady 100gr ELD-VT.

[okiecat]

Thanks for the great thread, I too agree with the Sako theory of barrel making,and would include CZ. Have you put a bore scope down that barrel. It sounds like the 6.5 is very chamber friendly. If you dont mind, what part of the country are you hanging out? Looks great. When it works dont mess with it, must be your policy.

[LRRPF52]

Thanks for the great thread, I too agree with the Sako theory of barrel making,and would include CZ. Have you put a bore scope down that barrel. It sounds like the 6.5 is very chamber friendly. If you dont mind, what part of the country are you hanging out? Looks great. When it works dont mess with it, must be your policy.

I need to bore-scope it and look at the chamber, because this has an actual SAAMI chamber with the compound throat. I’m interested to see if the initial half degree leade is still present. But it shoots the same as it did out of the gate, so nothing to complain about.

This 100gr ELD-VT load at 2730fps seems slow for a 24” barrel, because that’s 18” barrel velocity with a 100gr.

I worked up loads with my first 16” AA barrel with 100gr Nosler Ballistic Tips and 8208XBR that did 2675fps about 14 years ago.

With cut-down 94gr GMX monoliths, the 17.6” did 2800fps using CFE223.

In Hodgdon’s data, they did 2900fps with the Nosler 100gr Partition in top of LeveRevolution, 2873fps with CFE223.

If I loaded the 100gr ELD-VT with Hodgdon’s LVR or CFE223 data in the 17.6”, it would give me:

2759fps with LVR
2734fps with CFE223

That’s going to have significant improvements over the factory load downrange. It will move my drop from 10.8 mils to 8.9 mils at 1000yds, with only 2.2 mils drift in a 10mph full vale wind.

It will out-perform the 6mm ARC with 1-8gr ELD-M substantially at those speeds.

Hornady is showing a max of 2575fps from an 18” AR-15 with the 108gr ELD-M. I know some guys have pushed it to 2650fps from 18”, but it still loses to the 100gr 6.5mm ELD-VT.