This will be used 100% of the time from a deer stand/blind. Engagement distances on deer and pigs from 50-180 yards. I'll likely slap a Luepy Mk5 2-10x with a piggyback ACRO P2 on top and it will be shot suppressed at all times. For the 6 ARC I am leaning towards the Hornady 103's and for the 300 BLK I'd run the Barnes 110's. So what says the hive, do I go with the shorter, tried and true 300 BLK or do I give the 6 ARC shorty a whirl?
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12.5" 6 ARC vs. 9" 300 BLK
- Thread starter Tex68w
- Start date
If you’re sticking within 200yds then I see no reason to go with the 6ARC. However, you would have more energy transfer and higher velocity with the 6ARC. About 900ft. Lbs. more according to the ballistics app for my rifles.
That was my thought as well and the 300 BLK ammo availability is much better literally everywhere compared to that of the 6 ARC. I have an 18" 6 ARC that I am really enjoying so I have been kicking around building a shorty for hunting use but it's strengths lie beyond 100 yds unlike the 300 BLK.
One of my buddies brought his 6ARC to go pig hunting, just my opinion but it hits significantly harder then 300. I checked, significantly more energy at 100 and 200 yards.
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You could also do an 8.5"-12” Grendel, which will hit harder than either of them.
From Precision Firearms published velocity testing of short barrels with 123gr SMK:
7.5 Bartlien at 100 Yards. Groups averaged 1.5 Inches 2000 FPS 123 Match King
8.5 Bartlien at 100 Yards. Groups Averaged 1.4 Inches 2100 FPS 123 Match King
10.5 Bartlien at 100 Yards. Groups averaged .9 Inches 2200 FPS 123 Match King
12.5 Lilja Blank Chambered by PF at 100 Yards. Groups .75 2300 FPS 123 Match King
14.5 Lilja Blank Chambered by PF at 100 Yards. Groups .5 2350 FPS 123 Match King
14.5 Krieger at 100 Yards. Groups averaged .38 2375 FPS 123 MatchKing
If you take that 8.5” barrel data with a 123gr SMK, an 8.5”- 9” Grendel will do:
80gr Hammer at 2550-2588fps
90gr at 2420-2456fps
100gr at 2308-2342fps
10.5” Grendel will do-
80gr Hammer at 2686fps
90gr at 2560fps
100gr at 2431fps
127 various current factory SKUs available for ammo as well, including the 3 new ones from AAC and their planned steel case.
From Precision Firearms published velocity testing of short barrels with 123gr SMK:
7.5 Bartlien at 100 Yards. Groups averaged 1.5 Inches 2000 FPS 123 Match King
8.5 Bartlien at 100 Yards. Groups Averaged 1.4 Inches 2100 FPS 123 Match King
10.5 Bartlien at 100 Yards. Groups averaged .9 Inches 2200 FPS 123 Match King
12.5 Lilja Blank Chambered by PF at 100 Yards. Groups .75 2300 FPS 123 Match King
14.5 Lilja Blank Chambered by PF at 100 Yards. Groups .5 2350 FPS 123 Match King
14.5 Krieger at 100 Yards. Groups averaged .38 2375 FPS 123 MatchKing
If you take that 8.5” barrel data with a 123gr SMK, an 8.5”- 9” Grendel will do:
80gr Hammer at 2550-2588fps
90gr at 2420-2456fps
100gr at 2308-2342fps
10.5” Grendel will do-
80gr Hammer at 2686fps
90gr at 2560fps
100gr at 2431fps
127 various current factory SKUs available for ammo as well, including the 3 new ones from AAC and their planned steel case.
Seems like a Grendel would have nothing but advantages: hits a little harder, cheaper ammo, better ammo selection, likely more reliable if running suppressed
On the Hornady website, it says the case capacity of 6.5 Grendel is 32.5 grains and for the 6ARC it is 34 Grains. If you look at the 80 grain 6 ARC data it looks like it hits a little harder then the Grendel with the same bullet. DISCLAIMER - I am not reloading guy and there may be some nuance that I am not getting.
Case capacity may or may not mean anything once you factor in bullet intrusion, and that varies significantly with bullet design.
I won't be reloading either, I will only use factory loaded ammo. For the 6 ARC that'd likely mean ELD-X 103's and for the 300 BLK I have always used the Barnes 110's with great success. Not interested in a Grendel as I don't want to add another caliber.
The more I think about it the more I should just stick with the 300 BLK, easy stuff and shortest OAL.
Grendel is in the 34-35gr, whereas 6mm ARC has a reduced shoulder position and has a little less case capacity at 33-34gr. 80gr is able to be fired faster from Grendel even at lower chamber pressure, and the current 6mm 80gr GMX has a low BC.
When I started comparing the Radar data to my real-world data out to 1000yds with that new Hornady 6.5 Grendel 100gr ELD-VT, the advantages to 6mm kinda disappeared, otherwise I would have one. I’ve shot some 6mm AR over the years, which is just Grendel necked down to 6mm, which felt recoilless with 105gr, but so does Grendel in those weights and shoots just as flat, drift within .1 to .2 mils on paper, overlaps on Radar data for some reason.
If the Radar data is overlapping/mirroring, that means the stated BCs aren’t really accurate for the speeds we’re seeing in the AR-15 at least. Same thing we went through with .308 back in the 2000s with the 155gr Lapua Scenar and its published BC of .547, which was much higher than the published BC for the 175gr SMK even. A lot of us naturally used the 155gr Scenars since why not get better BC and faster mv, but Litz got curious and ran his tests that showed the actual BC to be more in the ~.460 region G1, and his subsequent evaluation of manufacturer-advertised BCs showed there was a lot of marketing going on to sell product by using high velocity form factor comparisons at 300yds for most of the bullets on the market.
For the distances the OP is talking about, none of that matters much, though better BCs do retain impact velocity better within the short ranges too, but are basically academic. They do allow you to use a shorter barrel and smoke other cartridges though, like 6.5 Grendel vs 7.62x39 or 300 Whisper is not even fair no matter what you do. Take an 8.5” Grendel vs 16” 7.62x39 and the tiny Grendel still passes the 16.3” 7.62x39 by 175yds, not even shooting a very high BC bullet from the Grendel, just the 123gr SST with Litz BC of .462 (advertised is .510).
Not mine^
12.5" arc with handloads and depending on conditions it can stay super out to 1000 yards. It pairs as a great target rifle that you can confidently target shoot out to 600-800.
Barnes 300blk 110 tac tx is an awesome round.
300 blk also gives you the option to hunt and shoot sub sonic. With discreet ballistics selous you can confidently hunt deer with it at the distances you're shooting as long as you know your holds.
Longer barrel, supersonic to roughly 1k yards, great target shooting rifle.
Shorter barrel, supers, subs.
Either will take deer without issue.
Guess it would depend on what you'd rather own. I own both and would take either out depending on the mood I was in.
My 12.5" 6 arc
9" 300 blk
Yea I already own the 9" 300 BLK, I've had it since 2011, killed many pigs and a few deer with it over the years and even knocked down a stud Aoudad with it a few years back as well. I have an 18" 6 ARC setup for long range target shooting so I am good there, I was just trying to decide if adding a 12.5" 6 ARC made any sense over the 300 BLK!
5.56 with 77gr tmk is a nasty hunting round as well. You can look up a thread on rokslide with probably over 100 wound profile pictures on deer, elk, moose, bear, etc with that round. There are people taking elk at 400+ yards with it, shoulder shots dropping them quick. It's an incredible round if you were interested in going with a short 11.5-12.5 5.56 for inside 200 on deer.
Just Google 77 tmk elk and you should find it if you're curious/interested.
Edit, found the cheat sheet post. There is a link to another post for cheat sheet part 2.
More than just 77 tmk. Somewhat turned into a mostly tmk but also other 5.56 rounds
https://rokslide.com/forums/threads/223-for-bear-deer-elk-and-moose.130488/
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Yea, not interested in adding any new calibers and I don't reload so it takes a lot of the niche stuff out of the running as well.
I've thumbed through that thread on the slide in the past. I don't have any plans to add anymore 5.56 guns to the stable.
It's a 12.5" 6 ARC or a 9" 300 BLK.
Well just because arc is newer to me I'd want to use it personally and I also like building rifles and picking out the parts. So personally if it doesn't really burden you financially I'd build/buy it.
Having said that 300blk 110 tac tx or 188gr selous probably does less meat damage being solid copper vs a eld x or eld m.
12.5" 6 arc with the new hornady 80gr eld varmit match would probably make a great predator/varmint/pest set up in a compact package. I'm sure it would take smaller deer no problem as well.
To me, 300 BLK is meant for subsonic. 6 ARC is meant to fuck things up.
He just dropped a video showing terminal performance between 300 Whisper and 10.5” 5.56 NATO, which was interesting. Velocity wins. Ballistics testing starts at 3:08.
This is why I’m excited about the new extreme high velocity 6.5 Grendel work going on.
Think about a 12” doing over 3340fps without pushing the pressure.
Bye-bye long barrels.
I'd agree that subsonic is where it shines, no doubt, but I have killed too many things with it over the last 12 years with supers to deny that it doesn't work quite well inside of 200.
That's in gel and the best round available for 300 blk wasn't tested.
110 tac tx definitely kills stuff and had been doing so reliably for a while.
Go shoot a good size hog with a mk18 using 55gr m193 and then shoot it with a 9" 300 blk using 110 tac tx. Gel tests are good for extrapolating to some but not all things.
I love 5.56 and the 77 tmk, 64 gr bsb, 62gr bonded, 70 tsx, etc are awesome. But 300 blk definitely has its place when you want more energy and penetration in a compact package. The rounds designed for 300 blk (not stuff designed for 308 and other faster moving .30 rounds) also typically have a much lower expansion threshold. So you can shoot those 6-9" barrels and still get reliable expansion out to 2-300+ yards with supers and subs. Now shooting subs at distance is it's own challenge but supers shouldn't be as much of an issue.
Is there a meaningful difference in velocity between a 6" and 9" barrel? I've got a PSA 8.5" barrel and am looking to upgrade that barrel. I like to shoot subs but want 150y capability with supersThat's in gel and the best round available for 300 blk wasn't tested.
110 tac tx definitely kills stuff and had been doing so reliably for a while.
Go shoot a good size hog with a mk18 using 55gr m193 and then shoot it with a 9" 300 blk using 110 tac tx. Gel tests are good for extrapolating to some but not all things.
I love 5.56 and the 77 tmk, 64 gr bsb, 62gr bonded, 70 tsx, etc are awesome. But 300 blk definitely has its place when you want more energy and penetration in a compact package. The rounds designed for 300 blk (not stuff designed for 308 and other faster moving .30 rounds) also typically have a much lower expansion threshold. So you can shoot those 6-9" barrels and still get reliable expansion out to 2-300+ yards with supers and subs. Now shooting subs at distance is it's own challenge but supers shouldn't be as much of an issue.
I have SBRs in both calibers. Both are great for what you’d be doing.
For velocities, I have gotten;
6ARC 13”
2464 with Precision Firearms 95 gr LRX load
2344 with the Hornady 103 ELD-X.
300blk 9”
2105 with factory Barnes 110 gr blacktips.
300blk 6”
1968 with the Barnes 110 gr factory loads.
2222 with Maker 85 gr factory loads (I wish I had chrono’d these out of the 9” and 16” barrels. They advertise 2550 out of 16”)
You can’t go wrong with either.
Imo the 5.5-6" is made as a bag or truck gun. Unless you absolutely need compactness I'd go with a longer barrel length.
I ended up selling the 6”. A guy wanted it, and for me it was more of an exercise in seeing if I could make it run. It was 100% reliable with or without a can with supersonic loads. With subs it was 100% if there was a can on it. I didn’t monkey around with gas port size, buffers, springs, etc.
Truth be told, for deer I grab my 350 Legend SBR now. Even with the can on the end it is handy to maneuver.
I like Mike but there was so much he left on the table with that video. Wrong ammo, wrong barrel length, etc...To me it wasn't a good comparison.
Well I've decided to do both, sorta. I am going to run the 300 BLK shorty in the blind this year but I'll be moving to a shorter can which will save me nearly 3" in OAL, a small win. I will also be building a second shorter 6 ARC upper, I just have to decide between a 12.5" or a 14.5".
Can you elaborate on the extreme high velocity Grendel work you're referring to? I'm guessing something with hybrid cases or some such?
My vote for the original question in the thread would be to get the 12.5" ARC, I have an 18" and 22" , and have been thinking about grabbing a 12.5" barrel too for hunting as well. I'm sure the .300 would work, I just really dig how well my longer ARCs work, and getting 95% of that capability in a stumpy version using the same ammo is an attractive option.
I’ll feel more comfortable once we have more baselines for pressure data, but even some of the conservative loads are looking to be game-changers right now. Normal brass cases. No chasing pressure beyond SAAMI. You don’t need to with Grendel. Some of the things going on with case metallurgy development will only add more performance that many will feel is unnecessary once they see the numbers.
My faster-than-factory 123gr hand loads with CFE223 are in the 45,700 - 48,900psi region, same as Hodgdon’s newly-published data with that powder and LVR as well, both generating the fastest speeds of any of the powders under 123gr.
I’m very conservative, where finding optimum propellant for superior gains makes more sense to me than brute-forcing a problem. Anytime you brute-force a problem, it creates 2nd-4th order effects that end up costing you in other ways. Look at some of the other cartridge development that has happened over the past 20 years, for examples of what not to do.
Oh ok, I've used CFE223 in the Grendel before to pick up a little speed over AR-Comp and 8208, I don't remember it being a radical increase though.
CFE223 is way too slow-burning for what I’m talking about for the Ultra High Velocity projectiles. It’s great under 90-130gr, which is a different burn rate range than what I’m working with.
So here are my options in regards to adding a shorter 6 ARC. I am not looking for suggested alternatives in regards to parts/costs, I am simply interested in hearing which route you would choose if given these options and why.
change the overall weight or length by much but it does keep my overall expenditure to lowest possible number. I don't know what the
POI shift will be like between barrel and can swaps but I can't imagine it'd be more than a MIL or so in either direction and easily rectified.
2. 12.5" upper: I can get a 11.5" LMT stripped upper and combine that with a 12.5" barrel from Noveske which I would have to convert of
course and then run that upper on my 300 BLK NFA lower. I'd likely swap/borrow the can from the 300 BLK on this upper since only one
can be in use at the same time. If I went this route I'd likely take the NF ATACR 4-16x42 F1 currently on the 18" 6 ARC and run it on the
the shorty. This would require me to get new glass for the 18" gun but I'd be ok with that as it would allow me to get little more top end
for the range sessions at distance. Added cost would be roughly $1500 but that doesn't include the cost to replace the glass on the 18"
upper, est. another $2-3.5K.
3. 12.5" complete rifle: This would require me to purchase a new lower and register it as an SBR. This would add another $1K to the
equation and would take a little more time while waiting on the NFA but it would afford me an entirely new and dedicated rifle. I'd likely
share the can from the 18" rifle if I go this route to avoid having to purchase another can along with the added stamp. Added cost would
be roughly $3000 but that doesn't include the cost to replace the glass on the 18" upper, est. another $2-3.5K.
- 14.5" barrel in current setup: I currently have a 18" 6 ARC setup built off of an LMT full rifle with the monolithic upper. This allows me to easily swap barrels in the field in mere minutes. I could get a 14.5" barrel and have it converted by D. WIlson and then swap out the current 18" barrel for the 14.5" barrel and run with that. I would only drop 5oz. weight here which isn't much but the gun would be 3.5" shorter which isn't anything to sneeze at when it comes to using it in the blind. This would put the rifle at 10lbs 6oz. (with can and mag) and 39.5" long which is the same length as my 20" 336 Marlin 30-30. Added cost would be roughly $1100.
change the overall weight or length by much but it does keep my overall expenditure to lowest possible number. I don't know what the
POI shift will be like between barrel and can swaps but I can't imagine it'd be more than a MIL or so in either direction and easily rectified.
2. 12.5" upper: I can get a 11.5" LMT stripped upper and combine that with a 12.5" barrel from Noveske which I would have to convert of
course and then run that upper on my 300 BLK NFA lower. I'd likely swap/borrow the can from the 300 BLK on this upper since only one
can be in use at the same time. If I went this route I'd likely take the NF ATACR 4-16x42 F1 currently on the 18" 6 ARC and run it on the
the shorty. This would require me to get new glass for the 18" gun but I'd be ok with that as it would allow me to get little more top end
for the range sessions at distance. Added cost would be roughly $1500 but that doesn't include the cost to replace the glass on the 18"
upper, est. another $2-3.5K.
3. 12.5" complete rifle: This would require me to purchase a new lower and register it as an SBR. This would add another $1K to the
equation and would take a little more time while waiting on the NFA but it would afford me an entirely new and dedicated rifle. I'd likely
share the can from the 18" rifle if I go this route to avoid having to purchase another can along with the added stamp. Added cost would
be roughly $3000 but that doesn't include the cost to replace the glass on the 18" upper, est. another $2-3.5K.
I have two LMT lowers, one of them is registered as a SBR.
I have two uppers, one MLOK and one quad pic.
I have the 12" Piston, 10.3" DI and 16" Piston for the quad.
I have a 16" DI and 16" 6 ARC for the MLOK.
I have 1 enhanced piston BCG.
I have 1 enhanced DI BCG
I bought 1 stripped bolt carrier and bought a bolt face and parts from JP for the 6ARC.
I have an Aimpoint T2, an EOTECH, a 4x ACOG, 1-8 ATACR, 4-16 ATACR.
If you can't tell, I say buy another barrel from D Wilson
I have the 6mm ARC, the 300 Blk, the 8.6Blk, the 300 Hamr, the 510 Whisper.
The 510 whisper is the energy king, it could easily take elephants.
But between the 6mm ARC 103 gr and the 300 BO Barnes 110 gr, ..my choice would be the 6mm ARC, for better range, velocity, and better BC, for energy retention, and trajectory.
At short range, both will get the job done...
The big boys, A picture of the 8.6 BO 350 gr Maker vs the 510 Whisper with 750 gr Amax.
The 510 W can shoot 1002 gr bullet at just 1100 fps with 2700 ft/lbs at the muzzle and arrive at 1000yds with 2000 ft/ lbs of energy, a 1.175 BC, helps.
Or the 510 350 gr copper Cutting Edge HP bullet with 4700 ft/ lbs or the 750 gr copper segmented Maker...lots of choices, and energy with the 510.
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Any interest in 375 Raptor or would you say 8.6 is where its at for a 308 based case?
Yes, I even bought a box of 375 bullets, and looked at the 45 caliber version too.
But I already have the 450 bushmaster with a fast twist for 500 gr subs.
There is a 416 Whisper also.
So I checked out the largest in the line, the 510 Whisper, and went with that...now I'm glad I did.
If ya go with the 6.5 twist in the 8.6 Blackout, its a good dual purpose cartridge. I scrapped the 3 twist as not workable for me.
My tests with both twist rates, bear this out.
I run the 350 gr Maker any speed up to 1700 fps. You are limited to 1000 fps of the 3 twist, even according to the manufacturer. And with 6.5 twist one can run any cheap lead bullet to maximum speed, like 2500 to 2600 for 200 gr Speer, or 2480 fps for the 225 gr. And over 1900 fps for the 300 SMK. With the 6.5 only twist, not the 3 twist.
Nothing wrong with the 375 Raptor, bullets are not as readily available or in as much variety, plus more expensive.
Since I already the 8.6 in 6 5 twist, the 375 & 8.6, are not that much different, so I went big.
I just decided to go to the 510, instead of the 375 or 416...plus, I already have a 416 Rigby.
The 510 compliments the 50BMG, as it's lot easier to carry around, and uses alot less powder.
I'm running a 24" on a bolt gun with a 6 5 twist.
My rough Faxon 3 twist was hitting max pressure like 3 grains below the 6.5 twist.
plus one can not run lead bullets and Maker 350 gr past 1000 fps and be safe with muzzle devices.
Yes I've run the, 230 gr eldx, 250, 225, 200, Speer, 160 Barnes, 300 gr SMK and Berger, and the 350 Maker.
The 3 twist has damaged my magneto speed bayonet and muzzle brake in one shot...have nothing but disdain for the Faxon 3 twist...but didn't give up on the 8.6 BO ordered a 24" 338 6.5 twist and chambered it , for a Rem 700 reciever.
I can go high velocity or subs with no fear of bullets coming apart ...with good accuracy.
My load data for supers is way over max in my Faxon 16" 3 twist. Example the 350 gr copper Maker is 1000 fps to 1050 max. velocity according to the manufacturer in the 8.6, but i run tbem at 1700 fps in the 6.5 twist, or 1100 fps.
My opinion if one chooses the 8.6 Blackout
get the 6.5 twist barrel it is dual purpose like the 300 BO, and not so limited and inaccurate as the 3 twist.
Some load development with the 6.5 twist with 100 yd accuracy.
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