Most of us are familiar at some level with the AR FOW.  At this point the AR has replaced the various milsurp bolt rifles as the preferred platform to build off of, hunt with, train with, etc.  There is a distinct difference between a work gun and a off duty piece. The off duty piece is the one we want to carry when we are out getting our mind right. This thread is geared towards the off duty AR.

Given that a small frame AR can be assembled into a very light, trim carbine with things like KMR-A handguards systems and MOE stocks; the platform lends itself to hunting and trekking on the weekend.   For our purposes, consider the usual range to be sub 200m, with occasional shots on steel to a maximum of 400m.  The carbine will not be shot a lot but will be carried extensively.  Consider its role as replacing the ubiquitous bolt rifle or .30-30 lever rifle that everyone shoots their deer and hogs with.   For the discussion, let's focus on the main three contenders that have both premium hunting grade and volume practice ammo available: 6.5 Grendel, 6.8 SPC, and .300 Blackout. The carbine may (likely will) be suppressed but will be fired exclusively with supersonic ammo.  Live targets will be up to the size of large deer or big hogs.
The question is: For a 16" barreled small frame AR carbine which is the prefered caliber outside of 5.56?

If you were building this carbine which caliber would you choose and why?
 

Original Post

I've had a fascination with 6.5 Grendel for some time and I don't know why, really.  Kind of flat shooting with good mid to semi-long (long for me) range ballistics from what I've been able to determine. There is cheap Russian blasting/informal range day ammo available. I believe there is good quality accurate/precision ammo as well.  Now there is 6.5 Grendel II, but I haven't researched the differences yet. I want to know more about the round but haven't found the time to really look deeply enough into it.  I'd really need to do my homework before I committed to it.  Until then it's 5.56 for me as that's what I'm already committed too, in terms of stocked ammo and gear.

Mojo/Mark
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Joined: 9/30/09
Location: Northern Nevada (Reno/Sparks)

I thought 6.5 needed an AR10 receiver? I know its certainly capable, Mark LaRue took an elk with one at like 400m. 

The .224 Valkyrie is making some noise as well in the market.

 

For me, Mlok fore end, either a CTR or fixed MOE stock, probably a 2.5-10x with BUIS, both folding. Caliber... probably 6.8, but I'd be looking hard at the 224 once more is known about it. SSA trigger.  Around here, deer run small, any of the rounds will do the job. 

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So low speed, i'm in Park.

"I could stand to hear a little more.." Jayne

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Joined: 6/14/03 1:02 PM

MrMurphy posted:

I thought 6.5 needed an AR10 receiver? I know its certainly capable, Mark LaRue took an elk with one at like 400m. 

 

6.5 Grendel uses small frame AR15

6.5 Creedmoor uses large frame AR10

I am unsure which one Mark used to drop his elk.

He used a custom Grendel, that was back around 2008ish.

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So low speed, i'm in Park.

"I could stand to hear a little more.." Jayne

Training is brief. Death is forever. PAY ATTENTION.

Joined: 6/14/03 1:02 PM

6.8 has the best choice of defensive & hunting ammo.

If one is using the TTSX, the .300 BLK works well.

6.5G gives a bit more range, but .224V is even better for punching paper at distance.

I'd also be inclined to just stick with 5.56 mm bonded or all copper loads and call it a day...

Longeye posted:
MrMurphy posted:

I thought 6.5 needed an AR10 receiver? I know its certainly capable, Mark LaRue took an elk with one at like 400m. 

 

6.5 Grendel uses small frame AR15

6.5 Creedmoor uses large frame AR10

I am unsure which one Mark used to drop his elk.

I think now that you bring it up my interest first started when I found that with basically just a BCG and upper swap on my 5.56 lower I could have a 2 caliber “system”. 

Mojo/Mark
__________________________
Yo homey, is that my briefcase...?
Vincent from "Collateral"
__________________________
You want the good life, you break your back, you snap your fingers, you snap your neck... Prong/Demon Hunter
__________________________

Because...I Can. 


Joined: 9/30/09
Location: Northern Nevada (Reno/Sparks)

I reload and have suppressors.

 

For me:

5.56:  for training (identical setup to the 300blk AR).

300blk: suppressed, and SBR'd for Home/ hunting etc. (110 grain TSX).

I have a LMT AR10 with a 308 and 6.5CM barrels if I want to reach out and touch something.

 

MOJONIXON posted:
Longeye posted:
MrMurphy posted:

I thought 6.5 needed an AR10 receiver? I know its certainly capable, Mark LaRue took an elk with one at like 400m. 

 

6.5 Grendel uses small frame AR15

6.5 Creedmoor uses large frame AR10

I am unsure which one Mark used to drop his elk.

I think now that you bring it up my interest first started when I found that with basically just a BCG and upper swap on my 5.56 lower I could have a 2 caliber “system”. 

Another option:  get an LMT MRP upper.

I have a 22lr, 5.56 and 300blk barrel that uses the same upper, same optics etc.

Just turn 2 torx screws (remove barrel and use a new bolt).

 

It saves a little money if you don't want to keep buying expnsive optics/lights etc.

 

 

I'm with Doc on this one.

Unless there is a need for something different, I would stick with 5.56mm.

Everything you need the gun to do, can be done with 5.56mm using the appropriate ammunition.

Choose a lightweight, precision barrel, lightweight handguard and stock, and something like a Short Dot, and call it a day.

Regards.

Mark

Formerly known as ML

I was reading conflicting stuff on the Grendel receiver size years back and hadn't had a reason to look again. I hunt with a 7x57mm and my theoretical replacement would still probably be a bolt gun. I don't have a ton of cash and can't get multiple new calibers.  Any spare AR would have to fill as many roles as possible. 6.5 or 6.8 still aren't common or cheap, where a Ruger GSR in .308 would fill multiple offduty options. An AR would be cheaper to assemble part by part though.

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So low speed, i'm in Park.

"I could stand to hear a little more.." Jayne

Training is brief. Death is forever. PAY ATTENTION.

Joined: 6/14/03 1:02 PM

"Consider its role as replacing the ,,,  .30-30 lever rifle that everyone shoots their deer and hogs with."

I think of the AR as a modern Win. 94.  

Sounds like you are going for Cooper Scoutish AR.

The Grendel is interesting but I don't know if it is worth trading off a 5.56 with a 1/7 twist and its ability to use solid copper bullets, heavy and light bullets.   

With the right bullet for the job and the same placement I'm betting it'll be just as dead with either the 6.5 or .224 bullet.

It'll be interesting to see what you come up with.

Part of what is driving this is my realization of how light, trim and svelte the AR is with a Gov't profile barrel and a KMR-A handguard.  It puts my Winchester Featherweight Compact to shame, as well as my former Steyr Scout Rifle.

I just can't develop any love for lever actions, despite the excellent work that 22F and the Hill Bros. are doing with their respective cowboy guns.

It may be Luddite of me, but I want a little more bullet mass and diameter than 5.56 offers for dedicated woods bumming.  The .308 AR is generally too much of a good thing in my experience.

Longeye posted:
stray round posted:

 Sounds like you are going for Cooper Scoutish AR.

 

The Cooper rifle principle is in my mind, but the Scout crowd/cult gives off a funny odor, so I hesitate to invoke Coopers name for this, even though what I am doing fits abut 90% with the general idea of the Scout rifle.

There are a lot of fervent socially awkward zealots in the current Scout rifle community. 

 

I have a “few” 5.56mm guns and a couple .300Blk guns.  I have taken deer with both flavors, though only one with the Blackout.  It did considerably more damage than the 5.56mm has done in the past using a 125gr SST handload.   But none of the deer survived either caliber.  The .300Blk works with cast bullets, suppresses nicely, and blows up 5.56 guns if someone accidently sticks a big bullet in a little hole.  I never take both flavors to the range at the same time  

Two guys I know have rifles in 6.8SPC and profess much love.  They just never seem to bring them to the range, or discuss reliability, or take them hunting...  IMHO The 6.8 needs a mid sized magazine and mag well to work properly.  

I’ve had zero experience with any of the 6.5 guns.  

Really it’s hard to justify any caliber other than the 5.56 in a handy sized AR shaped object that is affordable to shoot and does 99% of what needs shooting. 

Well, I guess by off-duty you are meaning ' in the woods'? Honestly I get where you are coming from in regard to maybe wanting more caliber but for off-duty I look at traveling with it, having it in the trunk for 'what if's' etc. 

What drives me to stay with 5.56 is frankly the availability of ammo in a variety of austere / semi-austere areas of the country.  I have been in Wal-Marts and small stores, bait shops and even convenience stores in some very rural and out of the way areas where you can get .223/5.56 at 0200hrs, have not been able to say the same for  .300 blackout or others.

Same goes with pistol ammo, 9mm I can find pretty much everywhere they sell ammo-even if it has to be ball, .45 ball maybe but others? Not as much.

I like the 300 for the AR but if you can't source ammo damn near everywhere in  a pinch it concerns me for anything other than a use where I am sure of the continuity of my logistical train.  I have a really nice and quite accurate 6.8 but it gets very little use for exactly this reason.

Antonius posted:

@Domestique - Where did you get a .22 LR barrel and BCG for your LMT MRP or are you using one of the conversion kits that utilizes the 5.56mm barrel?

Tony

I got lucky and found a barely used Spikes Tactical 10.5" MRP barrel on a gear exchange on another AR forum. 

Unfortunately they are no longer being made. The LMT MRP isn't as popular as it was back in 2008. The aftermarket support really died away. 

If you can find a used Spikes Tactical, jump on it. Mine has been flawless suppressed.  

 

 

Just built a 12.5" 6.5 with the new SBA3 brace for personal use.  Brace keeps it off paper and limits ATF issues for an off duty rig, 12.5 keeps it handy.

 If you load, the ELD-X is a monster from what I understand.  Currently shooting the factory 130 berger hybrids and liking them.  Very limited experience as of yet. 

Had a shaw barrel cut to my specs to see what I thought before committing to one of the 11.5" Lilja 6.5 barrels but planning to go that route if it pans out.  

Longeye posted:

Part of what is driving this is my realization of how light, trim and svelte the AR is with a Gov't profile barrel and a KMR-A handguard.  It puts my Winchester Featherweight Compact to shame, as well as my former Steyr Scout Rifle.

I just can't develop any love for lever actions, despite the excellent work that 22F and the Hill Bros. are doing with their respective cowboy guns.

It may be Luddite of me, but I want a little more bullet mass and diameter than 5.56 offers for dedicated woods bumming.  The .308 AR is generally too much of a good thing in my experience.

I can totally appreciate that! The Hill Brothers' videos and posts have me constantly contemplating about updating my 30-30.

I have a 1980's Marlin 336 that I would love to chop the barrel to 16" and thread it for a suppressor... but it would still be longer and much heavier than my 9" 300BLK AR. 

I mainly hunt whitetail in PA, and I'm hoping that next year they finally allow AR's for big game. Last year they allowed semi's for varmint/predator, this year they allowed semi-automatic shotguns for big game... hopefully next year I will be able to use my ARs.

 

Agreed re: 5.56.  Hard to beat for availability and choices of viable terminal ballistics.

That being said, I have a dedicated Kotonics built 6.8 AR that has a Shaw barrel and is boringly reliable, no matter what I feed it.  I reload for practice ammo, and the only factory ammo it sees is when I'm confirming zero, or hunting.  Speaking of hunting, I've taken about 7 or 8 bucks with it with zero issues (SSA ammo with Sierra Pro Hunter 110 grain bullets).

Rick R2 posted:

 

Two guys I know have rifles in 6.8SPC and profess much love.  They just never seem to bring them to the range, or discuss reliability, or take them hunting...  IMHO The 6.8 needs a mid sized magazine and mag well to work properly.  

Are they having reliability or accuracy troubles with them?

Are they the type of people that have multiple gun safes and take whatever flavor out each time?

I am just trying to understand the context of your remark.

An AR15 in 6.8 mm makes a great hunting rifle for all lower 48 game out to about 300 yds; hunt with 6.8 mm, practice with 5.56 mm.

As for home defensive uses, 5.56 mm has the advantage of optimal penetration depths when using barrier blind ammo; with the right ammo, 6.8 mm also works well in that role--some of the other choices, particularly .300 BLK using TTSX, tend to go a bit too deep for indoor use. I don't think I'd choose 6.5G for critical CQB defensive use.

Longeye posted:
Rick R2 posted:

 

Two guys I know have rifles in 6.8SPC and profess much love.  They just never seem to bring them to the range, or discuss reliability, or take them hunting...  IMHO The 6.8 needs a mid sized magazine and mag well to work properly.  

Are they having reliability or accuracy troubles with them?

Are they the type of people that have multiple gun safes and take whatever flavor out each time?

I am just trying to understand the context of your remark.

These are gun guys/hunters. Their guns apparently function well when the magazines are downloaded. Accuracy is much bragged about with both guns.  I don’t know if either is using the 6.8SPC specific Magpul magazines.    They have both flitted off to some new gun d’jour.

With the 6.8 allegedly about 80% as good as a .308 I want one to play with but I think some company needs to backup, design a magazine around the cartridge and then design a 6.8 specific lower that accepts the new magazine and AR-15 parts, uppers, etc. 

Longeye posted:

Incidentally, Consigliere voted for the 6.8 with his wallet over here:
https://www.lightfighter.net/t...-lwrc-6-8spc-carbine

Considering Consig buys just about 2 of everything cool, I don’t consider  him owning one much of an endorcement.   I mean other than high point, what doesn’t he own?  It’s like saying Ron Jermey votes brunettes with his Costco Polish Sausage (oops I crossed streams).  

Odd, but I agree with DocGKR on the 6.8SPC. Work gun is a 5.56mm, while I hunt west coast game and predators with a 6.8 upper using TSX. 

Participation does not equal Proficiency - Mike Pannone. Re-stated "Participation in one area does not equal Proficiency in another!"

 

Joined: November 2002

"I want one to play with but I think some company needs to backup, design a magazine around the cartridge and then design a 6.8 specific lower that accepts the new magazine and AR-15 parts, uppers, etc..."

Uh....That has been done.

DocGKR posted:

"I want one to play with but I think some company needs to backup, design a magazine around the cartridge and then design a 6.8 specific lower that accepts the new magazine and AR-15 parts, uppers, etc..."

Uh....That has been done.

Uh... No it hasn’t.   Unless I missed it manufacturers are still trying to shoehorn a cartridge with a 0.422” rim and 0.402” shoulder into a magazine dimensioned for a cartridge with a 0.378” rim and 0.354” shoulder.  This prevents the cartridges from stacking against each other properly. 

The 6.8SPC is a good enough cartridge in its own right that someone needs to create a magazine wide enough to allow the casings to stack properly and then an AR-15 lower receiver with a wider mag well for that new improved magazine.  Lowers are a @$100 part,  everything else could be normal AR-15 sized, you just wouldn’t be able to use it as a 5.56mm rifle by swapping uppers.   But the payoff is a rifle edging into .308 territory that doesn’t feel like you are carrying a truck axle.

I thought Barrett made a 6.8 only mag?

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So low speed, i'm in Park.

"I could stand to hear a little more.." Jayne

Training is brief. Death is forever. PAY ATTENTION.

Joined: 6/14/03 1:02 PM

Magpul and LWRC made a receiver set and magazines built for 6.8. It is slightly longer and wider than a standard receiver. It was from their Six8 series of rifles. Barrett makes a 6.8 mag but they are a full 30 round magazine, and slightly longer. I don't believe the internal dimensions are different between PRI/Barrett/CPD with the exception of they each use a different style of finishing the magazines which usually leads to CPD having less OAL available due to the overlapping metal and the spot weld. 

Extrabonez posted:

Magpul and LWRC made a receiver set and magazines built for 6.8. It is slightly longer and wider than a standard receiver. It was from their Six8 series of rifles. Barrett makes a 6.8 mag but they are a full 30 round magazine, and slightly longer. I don't believe the internal dimensions are different between PRI/Barrett/CPD with the exception of they each use a different style of finishing the magazines which usually leads to CPD having less OAL available due to the overlapping metal and the spot weld. 

I stand corrected.   Googlefu reveals that the LWRC lowers are @$700 but the design may become open source eventually.  I find myself in danger of building a new $2K rifle. 

Thanks for the info.

I will say that I would choose a 6.8 rifle for a rifle that isn't going to see thousands of rounds a year, due to the ammo availability and cost in comparison to 5.56. I personally went the 6.8 route  in 2014 or so and have been happy with mine. I am confident in the rounds ability to do what I need it to do within 300m or so. The hunting bullet selection is decent with 90grain(TSX, Gold Dot, TNT) all the way through 120-130(SST,TTSX) bullets with 110 grain Vmax and BTHP bullets in the middle of that range.   If you end up looking for 6.8 parts for a build, pay attention to the chamber specification. When the cartridge was introduced, manufacturers were using the original SAAMI SPEC chamber which can have pressure issues due to Remington having a dimensional discrepancy during original testing. Newer manufacturers should be using the SPEC II chamber that fixes those issues, and there is a chart out there showing what spec of chamber manufacturers are using. I have a feeling the 6.8 might have been more accepted or prevalent had Remington not had that issue from the get go.

If I could have only one as a general purpose rifle, I'd go for the 6.8.  I've hunted with a number of 6.8 AR's for at least 10 years now, probably longer.  I'm no smart guy, but I seem to recall a 16" barrel being the sweet spot for the 6.8.  While it and the Grendel are pretty similar to 500yd, I think the Grendel thrives as a long(er) range cartridge and likes long barrels for that purpose.  That and the 6.8 has a pretty wide variety of factory loads where the Grendel is much more limited, although for plinking there is some very cheap stuff out there (Wolf).  Where the Grendel likes long range, the Blackout thrives at shorter ones.  I own them all, but I love my 6.8.  To me, it's the best combination of size (AR15 w/16" barrel), weight (no 20+ inchers like the Grendel), terminal performance up to 3-400, and load variety.  Just my two cents.

 

"These are the rules. Everybody fights, nobody quits. If you don't do your job I'll kill you myself."

 

Joined: 04/01/2004     Location:  Twin Cities, MN

Add another vote for 5.56 here. If you're determined to skip it, though, then 6.5 Grendel gets my vote of the ones you listed. The 120-130gr bullets work well with it, including the new ELD offerings from Hornady. Factory ammo is available (if not as common as 5.56/.223), solid ballistics, and good terminal performance. 

.224 Valkyrie is also a valid option, but it seems there are still some bugs to work out. I got to check out a prototype JP a while back, and I was impressed with what I saw in terms of splash on steel and wind drift out to 840 yards. I wish @Qwa-Heatis was still posting regularly to chime in on it. Maybe the tag will get his attention.

If you reload, 6.8 is not the high mountain that some have tried to make it in terms of availability.  I routinely find NOS .277/.270 bullets for sale a number of places, from 90-130 grains although I don't bother loading above 115 grains.  It's an easy enough cartridge to reload for, too.  To repeat what others have stated, chamber spec is crucial.  

DocGKR posted:

Rick R2--glad to you found the info; this might be a subject I know a bit about....

I don't know much....but I definitely know not to ever question DocGKR when it comes to bullets...

Joined sometime in 2008.                  Live in Canada.        

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