Got out today with the Larue Ultimate 6.5 18" upper build.

[Gman6.5]

I shouldn't really say build because all you do is mount the barrel, hand guards and install the LT Rat Stock combo.

Only have 60 rounds on it so far but it looks like it might be a shooter?

I will be working up my own hand loads for this build once I collect about 100 pieces of brass for it.
.
Put some factory Hornady 123 gr SST's through it and I ended up with 1" groups at 100yds.

The grid on the site-in target are 1' and the grid on the Larue target are 1/4".

The Larue target was set up at 150 yds and the groups opened up to 2+ inches there and I'm not sure why that happened? You would think that only 50 more yards wouldn't make that big of a difference, but of course the barrel is still new and maybe that's a factor?

I checked to make sure everything was tight and the barrel is torqued to 50 foot-pounds as per the Larue instructions and I'm wondering if maybe I need to go a little tighter, because I believe I remember reading here to go with more torque for Grendel barrels than you would for a 5.56?

Anyways below are the targets, and circled in red are not flyers but are three shots I took to zero to the center. Any other flyers other than those are me.

I did use a front and rear rest which were pretty solid and I do get 1/2-3/4" at 150 yds with my Larue stealth 18" useing 77 gr SMK's and Berger 77 tactical's with this same method.

[ATTACH=CONFIG]12360[/ATTACH]
[ATTACH=CONFIG]12361[/ATTACH]
[ATTACH=CONFIG]12362[/ATTACH]

[BCHunter]

Nice looking rifle, the 123 sst's are one of the finickiest bullets to get to group in a grendel. So that may also have contributed. The 123 eldm black is a more universal round that most rifles will shoot moa with.

[Kswhitetails]

My LaRue runs factory Hornady about the same. Try Federal American Eagle 120s, or 129 SSTs. Wink.

[Gman6.5]

Nice looking rifle, the 123 sst's are one of the finickiest bullets to get to group in a grendel. So that may also have contributed. The 123 eldm black is a more universal round that most rifles will shoot moa with.

Thanks!

Yes, that sounds familiar.

I noted that most hornady's in 223 builds are very finicky and I ended up just exclusively using their 75gr BTHP's which was the only one that grouped decent for me and they are much cheaper than the Sierras which I save for good days.

I also tried their newer 73gr ELD's and did not have very good luck with those either.

This coming weekend after work I'm going to pop another 40 threw it to get an even 100 brass and start a load work-up with some Sierra 107 and 120's I have from my last Faxon build that went south.

[Gman6.5]

My LaRue runs factory Hornady about the same. Try Federal American Eagle 120s, or 129 SSTs. Wink.

Thanks I'm hoping my local shop will order those.

Once I can get some dies again I will probably exclusively use my hand-loads.

I got into Grendel last year and had a mediocre experience with a Faxon barrel build and the Grendel project went to the back burner until I got the bug again over the past couple of weeks.

Had a couple of hiccups with not locking back on the last rd with this one and I switched to a carbine buffer from an H and also realized I never lightly lubed the inner buffer tube.

Once I did that the issue went away.

[revaew]

My LaRue runs factory Hornady about the same. Try Federal American Eagle 120s, or 129 SSTs. Wink.

My larue upper failed to eject every single it took with the Federal Ammunition. I got some weird jams with brass stuck, and getting mangled in, every conceivable spot.

[Kswhitetails]

My larue upper failed to eject every single it took with the Federal Ammunition. I got some weird jams with brass stuck, and getting mangled in, every conceivable spot.

Something is wrong. I've never had my LaRue sputter, on any factory or reloaded round, in any circumstance.

I had a bad Elander mag cause a bolt over, but I've bent it back in line, and never had a hiccup since.

I just put more than 200 Federal 120 AE, and GMM loads in a range and match setting last weekend, and not one failure that wasn't self induced (left the chamber flag in). Not a single hiccup. Two 24 round elander mags used.

Spend some time figuring out the issue, and call LaRue, they'll take care of you if it's their issue. I'd almost guarantee its not though, probably mag related. I'm sitting here thinking about it, and I can't remember a single ftf or fte. I'm sure it's happened, but I can't remember it doing so. The one mag induced bolt over aside, that is.

[LRRPF52]

My Stealth 2.0 complete rifle is smooth as silk.

Feels like a polished and tuned race gun when you hand-cycle the action or shoot it, and it doesn't even have adjustable gas or custom recoil systems.

I field-stripped the BCG recently, and noticed how smoothly the bolt slides within the carrier as well.

It's the nicest factory AR15 I've ever owned, and I can only compare it to a tuned JP when describing the way the action feels.

[Redomen]

Very nice

[Gman6.5]

My Stealth 2.0 complete rifle is smooth as silk.

Feels like a polished and tuned race gun when you hand-cycle the action or shoot it, and it doesn't even have adjustable gas or custom recoil systems.

I field-stripped the BCG recently, and noticed how smoothly the bolt slides within the carrier as well.

It's the nicest factory AR15 I've ever owned, and I can only compare it to a tuned JP when describing the way the action feels.

I'm really happy with mine.

It ran smooth for the last two boxes after I lubed and wiped down the buffer tube. I am also beginning to wonder if my issue was mags and that it running smooth after was just a coincidence ? I did have a couple bolt ride-over's.

I wonder if I need to adjust the lips on the magazine? I did take some emery cloth the day before to get rid of any burrs to smooth things out .

The ride over would mostly happen after the last round was fired and the bolt would not lock all the way back but come forward a bit and stop.

I also had two cases get dented from not going all the way into the chamber. Seemed like the bolt was moving too fast forward before the case could come all the way up into the mag lips and the bolt cought it midsection instead of behind the head.

[Gman6.5]

Very nice

Thanks man!!

[LRRPF52]

One thing to consider when shooting in all this hot weather, is to use a heavier buffer with the MLGS 18" barrel.

MLGS 18" combos are really one of the main sources of problems trying to find a nice balance between cyclic rate and excessive gas.

Since the port is closer to the chamber than RLGS, you have more port pressure, combined with a lot of plug dwell time with the projectile.

When shooting lighter-weight ammo in the 100-110gr class, it's probably about ideal (sans the Wolf steel case).

Shooting 120gr +, you start to see more back pressure into the system, which causes early unlocking and/or faster cyclic rate.

Faster cyclic rate is hard to tame on the return stroke when looking at the magazine and cartridge stack, as the mag spring is now struggling to get that stack up into presentation when the BCG is headed home after bouncing the bumper pad on the back of the buffer off the inside of the RET.

[Gman6.5]

One thing to consider when shooting in all this hot weather, is to use a heavier buffer with the MLGS 18" barrel.

MLGS 18" combos are really one of the main sources of problems trying to find a nice balance between cyclic rate and excessive gas.

Since the port is closer to the chamber than RLGS, you have more port pressure, combined with a lot of plug dwell time with the projectile.

When shooting lighter-weight ammo in the 100-110gr class, it's probably about ideal (sans the Wolf steel case).

Shooting 120gr +, you start to see more back pressure into the system, which causes early unlocking and/or faster cyclic rate.

Faster cyclic rate is hard to tame on the return stroke when looking at the magazine and cartridge stack, as the mag spring is now struggling to get that stack up into presentation when the BCG is headed home after bouncing the bumper pad on the back of the buffer off the inside of the RET.

Thanks.

I started out with the carbine buffer and spring that came with the Larue upper package and that was where I had the first trouble's.

The spring that came with the Larue was shorter then my spring I already had in my lower that has about 7-800 rds through it. The tip of the spring is painted white.

I ended up switching back to my original spring and still had lock-back issues but when I lubed the buffer tube it ran without issue for the last 60 rds.

I wonder if I should leave it alone for now and see if a few hundred more fired through will it run good and than leave it that way it is?

I also have a spikes t-2 that is just a tad heavier than an H-buffer I could try?

[revaew]

Something is wrong. I've never had my LaRue sputter, on any factory or reloaded round, in any circumstance.

I had a bad Elander mag cause a bolt over, but I've bent it back in line, and never had a hiccup since.

I just put more than 200 Federal 120 AE, and GMM loads in a range and match setting last weekend, and not one failure that wasn't self induced (left the chamber flag in). Not a single hiccup. Two 24 round elander mags used.

Spend some time figuring out the issue, and call LaRue, they'll take care of you if it's their issue. I'd almost guarantee its not though, probably mag related. I'm sitting here thinking about it, and I can't remember a single ftf or fte. I'm sure it's happened, but I can't remember it doing so. The one mag induced bolt over aside, that is.

my mags worked very well with hornady ammo. no issues at all. It only happened with the federal ammo, in all of my magazines. I had a few brass over bolt issues that ive never had before in any of my guns. I wouldnt think it was a magazine issue if the only thing that was different in my setup was the rounds being used?