I always wanted an SBR, but didn't want to ask permission from unconstitutional continuing organized crime rackets to build or buy a decent compact AR15, so I stubbornly refused to apply for an SBR stamp and keep everything 16" or more.

These new pistol braces changed that, especially with the Maxim Defense and SB Tactical models.

After becoming familiar with real-world 6.5 Grendel ballistics and seeing the actual supersonic reach, I wondered if there was a short barrel/bullet combo that would stay supersonic out to 1000yds.  While getting close, most programs showed supersonic reach out to maybe 850yds from a 10.5" with 123gr Scenar or SMK (using about a .260 G7 BC), 875yds for an 11.5", and 900yds for a 12.5" barrel.  These are still very impressive numbers for a compact weapon that is PDW-sized, but still not breaking the 1000yd mark.

Nosler recently introduced the 130gr RDF with a G7 BC of .307 (.615 G1).  From a 12.5" Grendel Pistol or SBR, 1000yds supersonic reach is now possible with that bullet, according to the G7 drag model.

So now we're looking at an under-the-coat or inside the car gun that works extremely well for Close Quarters, then can be used to hunt medium game with, as well as shoot effectively out to long range with.  It has 1 mil of drift at 450yds, and 2 mils at 800yds, 2.8 at 1000yds, assuming a 2230fps mv with 1/8 twist.

Here is where I'm at currently.  I'm looking at some of the new compact, high factor variables right now for optics, either NXS8 or March 1-8 Mini.

TBAC Ultra 5 7.6oz Titanium suppressor has been in jail since September last year, which will go on the end.



Next phase will be some function-testing, followed by load development.  I'm thinking of just going straight into 130gr RDF from the get-go.

Once I have a decent load, I'll start smacking steel from 200-1000yds.

The goal is to do a video showing CQM drills, running up the stairs, then making 1st-round hits at 600-1000yds.

Update: Test firing and Long Range Work

Just got done running a 2-Day Long Range course and had the opportunity to test-fire and extend the range on this little pistol out to 800yds.

I was anticipating cycling issues since I'm in new territory with the Maxim PDW brace, mini buffer, and this barrel combo with CLGS, but it was flawless.

I tested first round hold-open with one round of 123gr American Gunner, locked back beautifully.

Then went through a mag while field-zeroing/holding at 200yds.  Everything ran fine, ejection is very positive at 4 o'clock, slings the brass out 15ft away.

Saturday, I dialed my reticle into POI at a rough 100yds, and proceeded to engage steel from 400yds to 800yds with at least a 90% hit rate, as I was figuring out the trajectory difference between this 5.56 GRSC reticle and the actual Grendel ballistics in that scope.

Here's a picture of Buffalo Canyon from a previous DM Course.  If you look at the top of the buttes on the left, then come down to the base of the cliff, that's where the 800yd steel is.



Out to 500yds, everything with the 5.56 M4 62gr reticle was dead-on center-punching the steel like it was easy.  For 800yds, I used 700 plus one dot below the 700yd line for repeated hits on the steel buffalo.

Recoil is noticeably more than a 16" or 18" lightweight Grendel, but it's a much smaller gun with a stiff recoil Maxim Defense spring that is very positive in returning the BCG into battery, love it.

No steel was safe within my view, and it only goes up to 4x.

Using 2 different Elander mags, a 17rd and 24rd, it felt like everything was tip-top and absolutely no hiccups.

I'm interested to see how this sucker is going to do with 107gr SMK and 130gr RDF, as well as 95gr Controlled Chaos.

Using the Hornady American Gunner, the wind drift is a lot more than a Scenar, maybe 1.4 mils for me at 500yds.

With 123gr Scenar, it's 2.5 mils at 1000yds at North Springs (6600ft elevation), supersonic to 1150yds, assuming a 2230fps mv.

This is what the GRSC reticle looks like:


The dot below 700 was dead-on for me at 800yds in the conditions we were in yesterday.

If I could start this build again, I would order the LaRue UU kit or the LaRue Stealth 2.0 upper/handguard combo with the 10.5" handguard.

The rail on the handguard I have is pretty sharp and will need covers.

I would also use a LaRue scope mount.

^^^

What 12” barrel would you go with?

I haven't accuracy-tested this Faxon barrel at 100yds, but it sure is so consistent at various distances that all my impacts were within 2 MOA as observed by my spotter with an HD Razor Vortex spotting scope from 400yds to 800yds, and that was with the GRSC on 4x using dots and stadia lines for my aiming points, not a target scope with fine crosshairs.

To say the least, I'm genuinely very stoked about how this little blaster is turning out so far.

Barrel-wise, you could order one from PF to your specs starting with whatever tube you wanted to start with, whether it be Criterion, Lilja, or Bartlein.

Ballistic Advantage makes a 12.5" barrel, but all the feedback I've seen so far is that they are ported for suppressed use, and short-stroke with a lot of factory ammo unsuppressed.

It would be awesome if LaRue made a 12.5" option for the Ultimate Upper kit.

He does have the SUURG upper available, meant to mate with its own slip-over suppressor as a complete integrally suppressed system.

I'm planning on testing mine out tomorrow, and will let you know how it cycles with the 123 gr. American Gunner.

Okay, here's the range report for my Ballistic Advantage 12.5" barrel:

The first 10-15 rounds or so were sluggish. The bolt would lock back, but it was catching on the carrier and not the bolt. Ejection was weak, and around 4:00-4:30.

After the initial break-in, it really seemed to smooth out quite a bit. Ejection improved considerably, and was dropping brass in a pile at 3:30-4:00, about 6-8 feet away. Even Wolf cycled and ejected normally, at around 3:00. LRBHO was now working as intended, locking all the way to the rear.

Hornady American Gunner was clocking in at 2,245 fps out of the 12.5" barrel, and around 2,400 fps out of a Faxon 18" barrel. I still need to dial it in a bit more at 300 yards accuracy-wise, but overall it shot well. I finally have enough brass saved up now to start working up some handloads, which should help a bit.

I think the barrel might be on the verge of being under-gassed, but it ran good enough for me once it broke in a little. Overall, I'm very happy with the way this build turned out.

Interested and want to follow progress. I have a 300bo SBR that I'm leaning toward rebarreling for a grendel.

@LRRPF52

Your work with the 6.5 Grendel has definitely been inspiring, and I'm looking forward to getting a chance to try mine out beyond 300 yards.

You have a bit of an elevation advantage, but even at the 1,000-2,000' elevation that's common around here, it still has plenty of reach for hunting purposes.

I had fun shooting some steel at 300 yards today. I would often have trouble hearing whether 5.56 hit the steel target or not, but the 6.5 Grendel made it very easy to see and hear the hits. This really is a great cartridge for such a lightweight and adaptable platform.

Here's where my hold was for 800yds with 123gr Hornady American Gunner, .450" G1 BC.

I think my zero is around 150yds after crunching a bunch of variables with a ballistics program.

I love this reticle:

This is relevant to my interests. Currently playing with a 12" Odin barrel SBR, staying with Hornady Black ELD-M 123's for now, but if reloading it would be difficult to ignore the 123 Scenar. Actually, it's been awesome so far, but can't settle on which optic should be on there long term. The new 1-8 Nightforce is really tempting.

Yes, the NX8 is an awesome scope.

I would love it if they put a GRSC reticle in it with drop stadia out to at least 12.

My GRSC 1-6x24 Norden Performance scope should be here today.

I was going to get either the March 1-8, or NX8, but after being reminded of how user-friendly the reticle is in my 1-4x24 GRSC on the 12" Grendel, I got the Japanese glass/construction Norden instead.

I think it's the most ideal combo for a compact Grendel.

After seeing what my 1-4x is capable of with 6.5 Grendel, I would feel totally comfortable with it out to 900yds with any of my 6.5 Grendels at this point.

It would handle 1225yds on my .260 Rem or 6.5CM with 130gr Berger or Nosler RDF.  The 800yd stadia line on the 1-4x is at 10.5 mils.

Any idea why the GRSC scopes aren't more popular?

They don't have a huge marketing effort behind them.

LRRPF52, How long is the handguard on your FDE pistol?
Thanks

Man, how you like that brace? I'm building an AR pistol now and I want that brace.

Exactly 10".  I would have preferred a little longer at 10.5" like the LaRue Stealth option gives you.

The barrel nut for this handguard is way heavier than it needs to be also.

I really like the Maxim PDW Brace.  Got it on a special at SHOT Show, along with a bunch of others.

I also have the SB Tactical brace that looks almost exactly like it, but it has a standard-length (but unique) RET, so doesn't collapse as small as the Maxim.

SB recently came put w a new telescoping brace that fits on a standared M4 reciever ext (or a Vltr A5) and works just like an M4 stock in its adjustment.  Somilar to the tailhook mod 2 but the new SB has the soft rubber arm loops rather than being very ridgid and square like like the Tailhook.  It is only like $120 too!  But not as compact as the Maxim collapsed.

Very cool work, LRRP.

If I didn't already have a Creedmoor, and felt like adding another cartridge, I'd be all over the Grendel.

The Grendel and Creedmoor compliment each other well. I love both cartridges.

I really enjoy my 12.5 BA SBR. I have had some function issues...can’t tell for certain if it’s magazines or the gun...but it is accurate.

I’d have to look back but I think the best group to date is a four shot .855 in group at 100.

Once I get the function lined out, it will be my HD SBR.

Excellent performance from a short barrel!

I am open to convincing. I have another AR build planned, and it would be no trouble at all to repurpose that to be a Grendel instead of 5.56.

Yep.  I have two CM and three Grendel.  They are great.

Nice.

Nice work OP.

Will that bring something up now that there are some really light weight 308 size guns like by patriot ordinance and what not why bother with Grendel when you could just build a Creedmore?

The lightweight ar10 platforms are $3k plus.   Also not quite as light as an ar15.  I have 2 that are under 8lbs with glass and ammo.

I also like the interchangeably of the ar15.  Any ar15 can swap major parts with others.  Not so with ar10s.   You need to be careful when buying parts for the ar10. That and as mentioned above most ar10 parts are at least 2x the cost if not more.

LRRP you rock and I've been following your posts for awhile.  For a few years now I've determined that my next build will be a 12.5 (pistol), 14.5 (pinned), or 16" grendel to go with my Specwar 762.  Awesome little pistol you've got there.  Good work.  I'm interested in seeing 100yrd groups, especially if you end up testing the 129gr ABLRs, which I was initially turned onto from some of your previous posts for the Grendel.

Nice view.  Glad you no step on snake.  Nice pistol and gorgeous snake.

LRRP: Would you mind providing some dimensions on that little suckah- weight, length with stock extended/collapsed? Cheers!

Well that is true

Empty weight with 1-4x GRSC and mount:  7lbs 13oz

Length extended: 30.5"
Length collapsed: 26.75"

It's piggish for a pistol build, main contributors being the barrel profile and that crazy huge steel barrel nut for the handguard.

Fantastic. I'll be going with a lighter barrel, rail, and barrel nut, but that gives me an upper limit to the weight. Thanks a lot.

That is one slick looking setup!

Is that a NSR handguard?  Old spare parts?

No, Rousch, which is a boat anchor and to be avoided if you want lightweight.

The barrel nut is about 4x as big as it needs to be, made from steel, and hard to time.

I can't recommend it at all, plus the rails are hand-shredders with no de-edging at all.  Feels like concertina wire, so I had to cap it with a rail cover.

Like I said, I would use the LaRue Stealth 2.0 upper/handguard combo if that had been available when I started the build.

Another good option would be an Aero no Forward Assist upper with BCM KMR, or 2A Armament set if you really want to shed weight.

Since I do like to shoot long range a lot, I wasn't so focused on racing to the bottom of the lightweight aspect, as a really lightweight gun will get squirrels on you behind the optic and trigger control-induced misses.

What buffer are you using?

The one that came with the Maxim Defense PDW kit.

It's very short, only 2.9 ounces, but the spring is very stiff.

Cycling has been very positive without a hint of wanting to choke so far.  Exceeded my expectations in that department.

Just got back from the range with some chrono data unsuppressed and suppressed.

Unsuppressed with the Bootleg gas system fully open, it wouldn't fully cycle 90gr TNT Federal American Eagle factory load, which is good to know.  Function has been 100% with 123gr Hornady American Gunner unsuppressed.  90gr TNT load probably uses a faster powder to punt the little varmint bullet out, and isn't driving the gas system with the port size and limited plug dwell.  This was common on the Alexander Arms 90gr TNT load, so they discontinued it many years ago.

Suppressed, it has plenty of gas for the 90gr TNT, enough so that I turned the gas down 3 positions.  Ejection was at 4 o'clock unsuppressed and suppressed with the final gas setting, very well-behaved, a joy to shoot.  I didn't notice any difference practically between shooting this suppressed and longer-barreled rifles that I've shot suppressed, as shooter's ear suppressed was very pleasant.  I don't ever want to shoot it without the can, not that it was crazy unsuppressed.  It's not bad at all unsuppressed, don't notice the difference between it and 16".

My younger kids' first shots from center-fire will be suppressed.

12" Unsuppressed 90gr TNT Federal AE, 91°F:

2702
2681 FTFeed
2670
2642 FTFeed
2654 FTLock on last round

Avg: 2670fps

Suppressed 90gr TNT
2675
2658
2660
2671
2685

2723
2700
2690
2682

Avg: 2683fps

120gr American Eagle Suppressed, 12" Grendel

2360   2411 2384
2375   2398
2374 2397
2387 2349
2384 2406

Avg: 2384 fps  (This is exactly 100fps slower than my 17.6" Lilja Grendel average speed across 20 samples.)

Accuracy results at 75yds, 1-4x GRSC Scope:

I haven't chrono'd 123 Hdy Am gunner out of my 12.5" BA.  But I assumed 2350 fps might be possible with my elevation and Omega 30 suppressor.

It turns out Primary Arms 4-14X ACSS scope reticle for 556 matches drops closely to that assumption if zeroed at 240 yards. I've only had a chance to try it out to 400-550 yards which isn't much of a test, but consistent first round hits from bench, bipod, and field expedient positions. For a cheap optic if it holds up it will do until I decide on something better.

JBM predicts the reticle will map closely out to transonic range. At some point I'll chrono various loads and mess around with Strelok reticle display before stretching out to 8-900 yds. It's a heavy scope for an SBR but it's mostly a range toy.  I can barely hear 556 hit the steel at 550 yards but the Grendel doesn't sound much different than a 308 hit.

Wow, 100fps.  Nice.   its just for an i terstate travel gun, I dont thik ill ever own another gun w barrel over 12.5”.

Turns out making the cartridge low pressure as per the sptial limitations of the AR evelope incidentally  made grendel on helluva SBR chamvering.

Is that a faxon barrel?

Yes, Faxon group buy barrel with Easy Engraving rifling.

Appears to be 50fps faster than speeds I'm seeing from other people's 12.5" samples with the same ammunition, but that could be the 91°F temp too.

I'm looking at getting a 13 7/8" barrel and pinning and welding a TranQuilo brake for my LaRue Stealth 2.0, which will bring it to 16".

Throw the LaRue TranQuilo can on that rifle without having to SBR or use adjustable gas.

I'm using Bootleg adjustable gas on this 12" with the TBAC Ultra 5, gas setting set to suppressed.  I thought I was one click away from S, but it's all the way over and ran both 90gr TNT and 120gr OTM with the same ejection, nothing crazy with the cyclic rate that I could tell.

Faxon 12" Group Buy Monster Logo barrel 5REE Rifling 1/8" twist
Group Buy Bolt with Monster Logo
Bootleg Adjustable Carrier
Maxim PDW brace, RET, stiff action spring, and small buffer (2.9oz)

Upper is an Alexander Arms standard forged upper with Mil-Spec dry film lube baked inside, checked for face squareness, Cerakoted FDE, with tunnel build-up.
Lower is a Precision Firearms standard forged option, with 50° funneled mag well and color-fill that I did.
Those receivers fit the tightest, while still allowing finger push of the Takedown pin.

Fire Control is LaRue MBT-2S, which makes shooting small groups a breeze.  I have the MBT-2S in at least 3 of my ARs now.  Love it.

I like the compact size of the GRSC 1-4x, but I'm looking for something with more magnification because this thing is fun to shoot at distance.  Thinking 1-8x.

Why are you looking to do a 14” permattach again?

Thanks for the info.

For my complete Stealth 2.0 Grendel so I can have a short profile with the TranQuilo can.

I'll probably do 13 7/8" pin and weld the TranQuilo brake.

I can already see my 12" Suppressed being commandeered by wife and kids.

Daddy has to have something to shoot suppressed as well.

Here's what another forum member did and what I'm talking about:

Attached File

^^^^ LRRPF52. I like where your head is at!

Also, what practical zero distance do you like? I’m considering a 12” or so and I already have an 18” LaRue. Typically shooting 123gr eldm or American gunner. Just wondering if you aren’t using a BDC reticle what you found works for you.