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12" ish Barrel 6.5 Grendel

warnera1102

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Several years ago I built a 20" grendel for a target AR. Well over the years as I have gotten more into night hunting the rig has gotten alot of additional weight (NV scope, IR light, Suppressor and etc) and length. I have another stripped lower/upper laying around and I have been tossing around the idea of building a lighter/shorter dedicated 6.5 grendel for hunting. I love the grendel round as it is very effective on the coyotes and pigs.

Does anyone have an experience with the shorter barrel 6.5 grendel? Most of my night shots are under 300 yards, so I feel the shorter barrel will be sufficient with a 8" can.
 

drewthebrave

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Ask and you shall receive:


If I move to a free state, a 12-14" suppressed Grendel is at the top of my to-do list.
 

LRRPF52

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I love the 12” Grendel. Load it with 129gr ABLR for a DRT medicine blaster, or monoliths from Maker like the Trex. 12” Grendel ballistics smoke 24” .30-30, 20” 7.62x39, 22” .223 Rem, performing more like a 6.5x54 M-S or 6.5 Carcano.

20190301_184113_zpsfgcbtjq1.jpg


fullsizeoutput_f2_zps3qydsyhd.jpeg
 

warnera1102

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Feb 25, 2020
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Ask and you shall receive:


If I move to a free state, a 12-14" suppressed Grendel is at the top of my to-do list.
Awesome, Thank you!
 

warnera1102

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Feb 25, 2020
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I love the 12” Grendel. Load it with 129gr ABLR for a DRT medicine blaster, or monoliths from Maker like the Trex. 12” Grendel ballistics smoke 24” .30-30, 20” 7.62x39, 22” .223 Rem, performing more like a 6.5x54 M-S or 6.5 Carcano.

20190301_184113_zpsfgcbtjq1.jpg


fullsizeoutput_f2_zps3qydsyhd.jpeg
Awesome I just picked up some 110 Makers for the grendel, I cant wait to see the carnage on a pig.
 

newguy2k3v2

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If you can bypass any feeding/reliability issues it probably is the best do all ar configuration I've found. I've got a 11.5 or 12.5 lilja and a 12.5 BA and they're both accurate enough with factory ammo. Mine is set up with a nx8, 15" rail and a vox-s mostly tucked in the rail. Peq15 out front and plenty of room for A lwts in front.
 
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warnera1102

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In hindsight I wish I would picked up a tbox or the Lilja for my target gun and had the barrel I have now (but in a 12" ) for a pistol build.
 

Crews

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    If you can bypass any feeding/reliability issues it probably is the best do all ar configuration I've found.
    This is the key statement here. My hunting buddy and I use our SBR’s in a fairly challenging environment. All suppressed, lots of dirt, and high round counts thermal hunting hogs at night. He has a 12” Grendel, it’s handy to carry all night and shanks hogs effectively. However, it CONSTANTLY has mag failures and feeding issues despite proper maintenance. And he’s tried every mag in the market with sample sizes larger than one.

    I am not trying to start a caliber war here, but I have had no such challenges with 6.8SPC or 300BLK (supersonic) SBR’s. While I agree the 6.5 pill is more desirable…. there’s basically zero real world difference between any of them at practical/realistic hunting ranges and scenarios (especially at night with mostly unknown distances.)
     
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    warnera1102

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    This is the key statement here. My hunting buddy and I use our SBR’s in a fairly challenging environment. All suppressed, lots of dirt, and high round counts thermal hunting hogs at night. He has a 12” Grendel, it’s handy to carry all night and shanks hogs effectively. However, it CONSTANTLY has mag failures and feeding issues despite proper maintenance. And he’s tried every mag in the market with sample sizes larger than one.

    I am not trying to start a caliber war here, but I have had no such challenges with 6.8SPC or 300BLK (supersonic) SBR’s. While I agree the 6.5 pill is more desirable…. there’s basically zero real world difference between any of them at practical/realistic hunting ranges and scenarios (especially at night with mostly unknown distances.)
    I have had issues with feeding the ELDM in the Elander mags, I ran a few of the Makers Rex bullets the other day without issues (alll supressed) I think the ELDM issues I caused by my reloads OAL being right at the max and the tip of the bullet hitting the feed ramps. I loaded the rex bullets a little shorter plus they do not have the pointed polymer tip. Typically how far are your shots? I had to commit to one the other night just shy of 300 yards to keep a dog from becoming educated (long story). The high round count wont be much of an issuse where I hunt as the pigs/coyotes are not as abundant in Eastern NC as other places.
     

    MtnCreek

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    Probably seating depth issue like you said. 120eldm has worked for me in 17rd elanders loaded to 15.
     

    Crews

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    Seems like a lot of the time it’s the mag followers getting hung up.

    For night hunting hogs with thermal it’s 200 yards and in. In my humble opinion anything past that your hit probability goes way down regardless of caliber if you’re shooting an SBR. Depth perception and accurate ranging is just limited with a thermal. The caveat of course is that my style of hunting is very dynamic, still hunting might be different.
     
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    LRRPF52

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    This is the key statement here. My hunting buddy and I use our SBR’s in a fairly challenging environment. All suppressed, lots of dirt, and high round counts thermal hunting hogs at night. He has a 12” Grendel, it’s handy to carry all night and shanks hogs effectively. However, it CONSTANTLY has mag failures and feeding issues despite proper maintenance. And he’s tried every mag in the market with sample sizes larger than one.

    I am not trying to start a caliber war here, but I have had no such challenges with 6.8SPC or 300BLK (supersonic) SBR’s. While I agree the 6.5 pill is more desirable…. there’s basically zero real world difference between any of them at practical/realistic hunting ranges and scenarios (especially at night with mostly unknown distances.)

    I’ve used Elanders, CPD, and the new Amend2 polymer mags in my 12” Grendel without issue, all suppressed. I’m using the Bootleg Adjustable Gas Carrier which makes a huge difference in the cyclic rate when using a high efficiency can (TBAC Ultra 5). I also de-edge, blend, and polish my feed ramps anytime I’m doing an AR build. I also chamfer the ejector so it doesn’t hang up cartridges when feeding from right side presentation in the mag. I also seal my gas systems so the block and tube don’t leak like a slip-fit DIY build.

    Have shot the following from the 12":
    123gr ELD-M from the Amend2 mags
    123gr Hornady American Gunner from CPD 25rd mags
    120gr Federal Match OTM from CPD 25rd mags
    90gr TNT Federal from 10rd CPD mags

    The only time I got it to FTFeed was shooting 90gr TNT unsuppressed with the heavy spring in the Maxim PDW brace’s short RET. There just wasn’t enough gas to get the BCG to retract fully against the added spring weight of the Maxim PDW set-up unsuppressed. Once I attached the TBAC Ultra 5, in ran 90gr TNT on all 4 gas settings of the Bootleg carrier with very positive cyclic rate/feeding, like it was a perfect combo.

    The other 12” runs everything it’s been fed, including 107gr SMK on top of 8208XBR, 123gr ELD-M, from older CProducts mags. It has the Maxim PDW on it, while mine has a standard carbine RET, spring, and buffer.

    If your buddy trouble-shoots his 12” Grendel, it might be the gas system or ejector and not necessarily mags. If it doesn’t feed from a large sample of mags, that tells you something it likely wrong with the gun.
     

    Eric_F

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    I love the 12” Grendel. Load it with 129gr ABLR for a DRT medicine blaster, or monoliths from Maker like the Trex. 12” Grendel ballistics smoke 24” .30-30, 20” 7.62x39, 22” .223 Rem, performing more like a 6.5x54 M-S or 6.5 Carcano.
    Slightly off topic, but what speeds are you getting (with what load) for the 129 ABLR from a 12"? I'm hardly getting 2300 fps from a 18", using 26.4 gr 8208. I've tried LVR and there's maybe room way over book max but still getting around that speed.
     

    Hogrider2000

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    I have two 6.5 Grendel weapons. Both pistols. One is 10.5", and the other is 12.5"
    I use on ly Alexander Arms mags, and shoot only factory ammo. Probably about 500 rounds thru each. NO malfunctions--and killed a fair amount of pigs.

    Very good round..
     
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    LRRPF52

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    Slightly off topic, but what speeds are you getting (with what load) for the 129 ABLR from a 12"? I'm hardly getting 2300 fps from a 18", using 26.4 gr 8208. I've tried LVR and there's maybe room way over book max but still getting around that speed.
    I don’t recommend using 8208XBR for 129gr class of bullets as it’s fast for that weight, but can be done safely if you follow standard procedures and published data.

    I’ve mainly used ball powders like CFE223 and LVR under the 129gr ABLR.

    Using a calibrated pressure test breech cut with a mid-life spec SAAMI reamer built specifically for that purpose by Manson Reamers, 2410fps from an 18” was achieved using CFE223 without exceeding 50,000psi, 10-shot string average.

    I ran some pressure ladders with it from an 18” Lilja several years ago as well that tracked right along with that. A 2.284” COL (won’t work from Elanders) allowed a 31fps increase over 2.271”, which doesn’t amount to a hill of beans difference other than on paper, but could help with finding a node.

    I haven’t shot any 129gr from my 12” yet. Running that load through a Grendel-specific internal ballistics engine shows a 12” doing 2246fps with that.

    Factory 90gr TNT does 2698fps avg from my 12”.

    120gr Federal AE does 2418fps.

    129gr ABLR doesn’t really care what speed you shoot it at since expansion floor is 1300fps, and BC is .553 G1/.283 G7 according to Bryan Litz analysis.

    97EA6AFA-3C3B-49FC-BD94-836862C68281.png



    Even if we assume a 2200fps mv from a short barrel, it still retains over 900ft-lbs out to 300yds

    100yds 2057fps 1211ft-lbs Zero
    200yds 1919fps 1055ft-lbs -5.7”/ .8 mils
    300yds 1787fps 915ft-lbs -20.9”/ 1.9 mils......8”/ 2.5 MOA/.7 mils drift for 10mph full value wind

    The numbers are all really similar if you shoot it from 11.5” and 10.5”.

    It gives you a lot of options for more compact, carry-easy hunting set-ups, especially with a suppressor.
     

    Eric_F

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    I don’t recommend using 8208XBR for 129gr class of bullets as it’s fast for that weight, but can be done safely if you follow standard procedures and published data.

    I’ve mainly used ball powders like CFE223 and LVR under the 129gr ABLR.

    Using a calibrated pressure test breech cut with a mid-life spec SAAMI reamer built specifically for that purpose by Manson Reamers, 2410fps from an 18” was achieved using CFE223 without exceeding 50,000psi, 10-shot string average.

    I ran some pressure ladders with it from an 18” Lilja several years ago as well that tracked right along with that. A 2.284” COL (won’t work from Elanders) allowed a 31fps increase over 2.271”, which doesn’t amount to a hill of beans difference other than on paper, but could help with finding a node.

    129gr ABLR doesn’t really care what speed you shoot it at since expansion floor is 1300fps, and BC is .553 G1/.283 G7 according to Bryan Litz analysis.
    Thanks, I only recently found some LVR in stock so I'll be working on that more, hoping to get over 2400 fps. But yeah, this data (in 36 F) is a good match to G7= 0.283, and they've been great on deer. I'm not in a hurry to build an AR pistol given current possible regulation, but I love this round.
     

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    *Nine

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    I don’t recommend using 8208XBR for 129gr class of bullets as it’s fast for that weight, but can be done safely if you follow standard procedures and published data.

    I’ve mainly used ball powders like CFE223 and LVR under the 129gr ABLR.

    Using a calibrated pressure test breech cut with a mid-life spec SAAMI reamer built specifically for that purpose by Manson Reamers, 2410fps from an 18” was achieved using CFE223 without exceeding 50,000psi, 10-shot string average.

    I ran some pressure ladders with it from an 18” Lilja several years ago as well that tracked right along with that. A 2.284” COL (won’t work from Elanders) allowed a 31fps increase over 2.271”, which doesn’t amount to a hill of beans difference other than on paper, but could help with finding a node.

    I haven’t shot any 129gr from my 12” yet. Running that load through a Grendel-specific internal ballistics engine shows a 12” doing 2246fps with that.

    Factory 90gr TNT does 2698fps avg from my 12”.

    120gr Federal AE does 2418fps.

    129gr ABLR doesn’t really care what speed you shoot it at since expansion floor is 1300fps, and BC is .553 G1/.283 G7 according to Bryan Litz analysis.

    97EA6AFA-3C3B-49FC-BD94-836862C68281.png



    Even if we assume a 2200fps mv from a short barrel, it still retains over 900ft-lbs out to 300yds

    100yds 2057fps 1211ft-lbs Zero
    200yds 1919fps 1055ft-lbs -5.7”/ .8 mils
    300yds 1787fps 915ft-lbs -20.9”/ 1.9 mils......8”/ 2.5 MOA/.7 mils drift for 10mph full value wind

    The numbers are all really similar if you shoot it from 11.5” and 10.5”.

    It gives you a lot of options for more compact, carry-easy hunting set-ups, especially with a suppressor.
    Are you willing to share what charge of LVR you're using with the 129s?

    I've got both 12" and 16" barrels and with 30.3gr of LVR and a 129 ABLR I'm seeing ~2400fps out of my 16" but I'm only seeing ~2160 out of my 12", which seems slower than it should be. At 60 degrees I'm only seeing 2200 fps out of that same 12" barrel with factory Hornady 123 SST loads, so maybe it's just a slow barrel?
     
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    shlouf

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    I used a 12" palmetto Grendel for a while until ammo got crazy last year, and I switched back to 223. Ran great with the 17 round e-lander mags.

    Strictly night hunting with thermal. 90% of shots under 100 yards, but the 123gr American gunner is hell on swine.

    hVQgf8n.jpg


    1oNiw8D.jpg
     
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    LRRPF52

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    Are you willing to share what charge of LVR you're using with the 129s?

    I've got both 12" and 16" barrels and with 30.3gr of LVR and a 129 ABLR I'm seeing ~2400fps out of my 16" but I'm only seeing ~2160 out of my 12", which seems slower than it should be. At 60 degrees I'm only seeing 2200 fps out of that same 12" barrel with factory Hornady 123 SST loads, so maybe it's just a slow barrel?

    I have CFE223 data for gas guns. Looks my personal LVR data is only under the 129gr SST in a bolt gun, so I’ll just post the CFE223.

    18” pressure test barrel/breech with mid-life cut SAAMI chamber with the compound throat
    Bullet: 129gr Nosler ABLR
    Case: Hornady
    Powder: CFE223
    Primer: CCI 450
    COL: 2.260"
    Start load: 29.0gr 2300fps
    Max: 30.4gr 2410fps

    Bullet: 129gr ABLR
    Case: Hornady
    Powder: CFE223
    Primer: Rem 7 1/2 BR

    2 different ladders with different seating depths shot from a 17.6” Lilja barrel, SAAMI chamber. Temp: 89* F/ 31.6* C

    1st Ladder
    COL: 2.284"

    30.0gr 2345
    30.3gr 2360
    _________________
    30.6gr 2427
    30.9gr 2453
    31.2gr 2501

    31.5gr 2441
    31.8gr 2548


    2nd Ladder
    COL: 2.271"

    30.0gr 2372
    30.3gr 2379
    30.6gr 2396
    30.9gr 2419
    31.2gr 2465
    31.5gr 2492
    31.8gr 2491

    Notice where the trend departures were. You could probably get more resolution on what’s going on with Base to Ogive measurements. Especially on a CLGS 12", I would not chase mv because of port pressure with ball powders and their effect on early unlocking, and unnecessary torsional loads on the lugs and extractor.

    I mitigate that as much as possible on my 12” with the Bootleg carrier, but I’ve only fired factory ammo through it so far. The original AR gas system and recoil system was really designed around fast-burning stick powders, one of which was 8208M in the late 1950s. Switching to the ball propellant caused a lot of those early problems with FTExtract, and necessitated the heavy rifle buffer as a rate-reducer to replace the original lightweight Edgewater spring guide.

    Going down to CLGS but with the added bore volume and lower chamber pressure of Grendel helps keep it under control, so my thoughts are to let the BC do as much work for you as possible if you’re looking for retained energy. If you just want fast mv up close, the varmint bullets are great for that and exhibit controlled expansion on medium game since they aren’t being slung at 3,000fps+ speeds.
     
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    *Nine

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    I have CFE223 data for gas guns. Looks my personal LVR data is only under the 129gr SST in a bolt gun, so I’ll just post the CFE223.

    18” pressure test barrel/breech with mid-life cut SAAMI chamber with the compound throat
    Bullet: 129gr Nosler ABLR
    Case: Hornady
    Powder: CFE223
    Primer: CCI 450
    COL: 2.260"
    Start load: 29.0gr 2300fps
    Max: 30.4gr 2410fps

    Bullet: 129gr ABLR
    Case: Hornady
    Powder: CFE223
    Primer: Rem 7 1/2 BR

    2 different ladders with different seating depths shot from a 17.6” Lilja barrel, SAAMI chamber. Temp: 89* F/ 31.6* C

    1st Ladder
    COL: 2.284"

    30.0gr 2345
    30.3gr 2360
    _________________
    30.6gr 2427
    30.9gr 2453
    31.2gr 2501

    31.5gr 2441
    31.8gr 2548


    2nd Ladder
    COL: 2.271"

    30.0gr 2372
    30.3gr 2379
    30.6gr 2396
    30.9gr 2419
    31.2gr 2465
    31.5gr 2492
    31.8gr 2491

    Notice where the trend departures were. You could probably get more resolution on what’s going on with Base to Ogive measurements. Especially on a CLGS 12", I would not chase mv because of port pressure with ball powders and their effect on early unlocking, and unnecessary torsional loads on the lugs and extractor.

    I mitigate that as much as possible on my 12” with the Bootleg carrier, but I’ve only fired factory ammo through it so far. The original AR gas system and recoil system was really designed around fast-burning stick powders, one of which was 8208M in the late 1950s. Switching to the ball propellant caused a lot of those early problems with FTExtract, and necessitated the heavy rifle buffer as a rate-reducer to replace the original lightweight Edgewater spring guide.

    Going down to CLGS but with the added bore volume and lower chamber pressure of Grendel helps keep it under control, so my thoughts are to let the BC do as much work for you as possible if you’re looking for retained energy. If you just want fast mv up close, the varmint bullets are great for that and exhibit controlled expansion on medium game since they aren’t being slung at 3,000fps+ speeds.
    Thanks for that data. I actually run the Grendel ARs without gas systems using side charging uppers to more or less make a straight pull bolt action rifle. They're just for hunting use and I liked the idea of having a compact, light, modular setup that uses easy to source off-the-shelf parts. I've always felt more comfortable making more precise shots with bolt action rifles, and without all the stuff moving around in the rifle these ARs feel like bolt guns to shoot.

    Anyways, my constant debate between the 12" and the 16" is that in my area I can take a 400 yard shot on a deer (which is about as far as I'd be comfortable taking a shot on an animal with one of these rifles) and while both barrels will easily keep the 129 well above the 1300fps expansion floor I'm just a bit cautious about the amount of energy retained by the 12" gun at that range, which is why I've been focused on trying to get as much velocity out of it as I reasonably can. Or perhaps I'm going about this all wrong and the energy really doesn't matter as long as I make a hit in the vitals and the bullet expands and penetrates.
     
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    LRRPF52

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    Even at 2260fps mv, you still have 847ft-lbs and 1720fps impact speed with the 6.5mm 129gr ABLR at 400yds.

    That’s the same numbers for a 170gr Winchester Silver Tip from a 20” .30-30 Lever Gun....at 200yds. (846ft-lbs, 1541fps at 200yds for the 170gr .30-30 Win, .256 BC)

    If you can consistently place the shot within the ~10” vital zone of deer at 400yds in field conditions, from field positions, the firearm/cartridge with 129gr ABLR is more than capable of putting a supersonic, highly-expansive, bonded bullet through the vitals.

    That makes a very nice little compact field package that rivals the performance of legacy rifles that have accounted for more deer killed than any other center fire rifle.