338 ARC

[LRRPF52]

I see these types of firearms as gateway drugs for your kids.

My kids love shooting suppressed, as I start them out that way (except for my oldest son, who shot an MP38 for his first gun experience).

For my younger ones though, they’ve been shooting suppressed 6.5 Grendel and Maxim9 a bit.

Once they were comfortable with those, it was funny to see my oldest daughter react with glee the first time she shot 9mm unsuppressed. “Whoah! Cool. It made a big bang!"

So those of us who have shot a lot of 300 Whisper already know it’s anemic on steel, no 2 ways about it, but still very fun at close range.

338 ARC will make hitting steel more enjoyable due to energy on-target that can clearly be heard when a 300+ gr impacts plates, vs 180-220gr.

The supersonic performance is secondary, but looking at their 175gr data, 44 Magnum muzzle energy/904ft-lbs at 300yds is still no joke. That’s of course from a 16” barrel, which I know I’m not interested in, but for those that don’t want to do 2 stamps.

LedZep said he’s being using a ThunderBeast FLY9 for his 338 ARC testing, which is a great suppressor, very light, very tough.

The approach Hornady is using with this increases chamber pressure into the low 40ksi range if I heard them right, which will cut SDs down into single digits.

I think an 8.5-12” 338 ARC would be very fun for the kids. Add it to their homeschool curriculum. There’s something about almost no noise at the gun and very loud impact on-steel that kids love.

 

[LRRPF52]

Here’s a blast from the past for the initial .338 Spectre ads:

 

[LRRPF52]

For those of you running 338 Spectre, have you been able to load a full 26rds in 6.8 SPC or Grendel mags and get feeding?

Any binding with the forward guide rib?

 

[st1650]

Cas des

Here’s a blast from the past for the initial .338 Spectre ads:

I remember those bipod being absolute dogshit.

 

[45-90]

Since 10mm Auto Mag has not been available, they've been cutting down 6.8 SPC brass and SR primers & running at 55,000 psi.
So the performance is very close to the 338 ARC at 52,000 psi.
Infact there is a fair amount of load data out there for the 338 Spectre from makers like Lehigh Defense, & on line data for the Spectre, that could be easily converted to the 338 ARC, since they are very close, in case capacity.

 

[LRRPF52]

Yup. Everyone saying this is effectively 338 Spectre with big industry support is right I think, along with Hornady expanding the Grendel case ecosystem under the ARC product lines.

338 ARC Subsonic Suppressed, embraces the AR-15 parts and ease-of-use market
6.5 Grendel (Hornady took Grendel to SAAMI way sooner than Bill A. ever thought it would happen.)
6mm ARC
22 ARC

 

[hseII]

Yup. Everyone saying this is effectively 338 Spectre with big industry support is right I think, along with Hornady expanding the Grendel case ecosystem under the ARC product lines.

338 ARC Subsonic Suppressed, embraces the AR-15 parts and ease-of-use market
6.5 Grendel (Hornady took Grendel to SAAMI way sooner than Bill A. ever thought it would happen.)
6mm ARC
22 ARC

I think they should do a 41 ARC straight wall & outsell the 350 & 400 legend.

I used to think straightwall was silly but now that I am in a straight wall state I get it.

 

[Mike Casselton]

Might as well go 450 ARC and use that 398gr .452 sub-x.

Basically a rimless 45LC, or a long 45 ACP

 

[hseII]

Might as well go 450 ARC and use that 398gr .452 sub-x.

Basically a rimless 45LC, or a long 45 ACP

IDK why Winchester did the 400 legend over a 41?

Hornady has a 190grain ftx already that would be perfect for supers.

The 450 BM is limited on magazine capacity to the point that I just don’t think I want one.

 

[Ledzep]

I think they should do a 41 ARC straight wall & outsell the 350 & 400 legend.

I used to think straightwall was silly but now that I am in a straight wall state I get it.

Shortly after the .350 Legend was released I (jokingly) took a pre-shouldered, basically straight tube 6mm ARC case to my boss with a .40 cal bullet seated in it and said, "Hey! Look! The 400 MYTHIC!!" to which he said, "What?! No. God No."

 

[hseII]

Shortly after the .350 Legend was released I (jokingly) took a pre-shouldered, basically straight tube 6mm ARC case to my boss with a .40 cal bullet seated in it and said, "Hey! Look! The 400 MYTHIC!!" to which he said, "What?! No. God No."

Look at the 41 offerings vs. the 40- I think it’s a logical move for the big H.

I’ll buy 3 please.

 

[hseII]

And while we are on the wish list,

Roll that 338-300PRC out already that all yall have been slaying everything with for years.

The world needs a modern .340 weatherby without the belt.

270ELDX @ 2850-2900 with a 26” barrels

Yes Please.

 

[45-90]

I think they should do a 41 ARC straight wall & outsell the 350 & 400 legend.

I used to think straightwall was silly but now that I am in a straight wall state I get it.

Yes it was done in 1910, called the 401 WSL and the 351 WSL earlier in 1907 for Winchesters then new auto loading rifles.
The 351 WSL was popular with cops and prison guards, and used to kill Bonnie & Clyde, along with a host of others that day.
Now Winchester calls them the 350 legend, and the 400 legend, basically reintroduced. Add a 400 grendel? Hornady just might...

 

[45-90]

Might as well go 450 ARC and use that 398gr .452 sub-x.

Basically a rimless 45LC, or a long 45 ACP

Might as well go 450 ARC and use that 398gr .452 sub-x.

Basically a rimless 45LC, or a long 45 ACP

 

[45-90]

Might as well go 450 ARC and use that 398gr .452 sub-x.

Basically a rimless 45LC, or a long 45 ACP

You can load 500 gr in 45 Colt 16" trapper win 94 but they go sideways...the 400 gr work great in win 94 and Rossi 454 carbine, 9 rounds of subs or high velocity.

 

[Mike Casselton]

IDK why Winchester did the 400 legend over a 41?

Hornady has a 190grain ftx already that would be perfect for supers.

The 450 BM is limited on magazine capacity to the point that I just don’t think I want one.

Magazine capacity, or lack of capacity isn't an issue for me.

Subs would just be a play toy or something to kill the occasional deer or hog.

 

[epeet]

@Ledzep

How do pressures compare to a subsonic .300BO?

Curious if suppressors rated for subsonic .300BO will be able to handle this cartridge (i.e. Octane 45HD).

I would think as long as you have the clearance (i.e. + .338 diameter on can), shouldn't be any issue. Still a very low pressure round with little powder, compared to a most rounds.

 

[hseII]

Magazine capacity, or lack of capacity isn't an issue for me.

Subs would just be a play toy or something to kill the occasional deer or hog.

I agree however after shooting a 450BM a few weeks ago,
I think there’s some energy to spare & the 41 would be somewhat easier to run both supers & subs with.

But I have already sent an email to the above folks to get on the waiting list for a .338 ARC barrel.

 

[Mike Casselton]

I think with subs, it's like drag racing engines. There's no replacement for displacement.
Electric nonsense excluded.

 

[epeet]

I honestly won't be surprised if as the requisite gun magazine articles start rolling out Hornady tells us this was just a request/project from the same folks who want 6mm ARC. Because those same folks already have the bolt/mags for this round, and are likely the one edge case where 50% more subsonic energy is actually useful. Sure, .458 SOCOM would be even mo-betta, but I've been puzzling over who wants to pay another +$.50 a projectile over 300 Black, just to get back some ME. Not hunters, not target shooters. So it seems like a strange product to drop unless there was already a contract in place.

 

[st1650]

Just recovered my 395 SubX from that buck.
380gr (96% weight retention) and expansion to 0.86in
Pretty hard to beat as far as subsonic performance.

 

[LRRPF52]

Shortly after the .350 Legend was released I (jokingly) took a pre-shouldered, basically straight tube 6mm ARC case to my boss with a .40 cal bullet seated in it and said, "Hey! Look! The 400 MYTHIC!!" to which he said, "What?! No. God No."

New for 2030!!!

 

[LRRPF52]

I honestly won't be surprised if as the requisite gun magazine articles start rolling out Hornady tells us this was just a request/project from the same folks who want 6mm ARC. Because those same folks already have the bolt/mags for this round, and are likely the one edge case where 50% more subsonic energy is actually useful. Sure, .458 SOCOM would be even mo-betta, but I've been puzzling over who wants to pay another +$.50 a projectile over 300 Black, just to get back some ME. Not hunters, not target shooters. So it seems like a strange product to drop unless there was already a contract in place.

They actually said something like this in the podcast, but it was before 6mm ARC in 2016.

A customer set wanted more effective range than 300 BLK that worked across wide temperature ranges.

The Soviets had this same problem with 7.62x39 suppressed, which was the main application Spetsnaz used it for after adoption of the AKS-74. I have a book written by and for Afghan War Spetsnaz Veterans that shows the weapons they used, the weapons the Afghans used, and how their main mission sets were basically trying to interdict weapons being smuggled in from Pakistan along the mountainous border region.

AKMs with 1PN34 NVD Scopes and PBS-1 Accumulators (Suppressors) and GP-25s:

Here’s a rare example of Spetsnaz with a suppressed AKMS under-folder in the background while the foreground poses with a captured M-1 Garand.

The AK-74 and AKS-74 were the main workhorses for most guys, but they had a legit subsonic suppressed requirement for picking Mujahideen off quietly. The problem with 7.62x39 subsonic was reliability across the temperature extremes. You can get it to run subsonic fine that cycles the action in temperate weather, but then the temps drop and now it won’t cycle. They tried playing with 5.45x39 suppressed as well with the AKS-74U and the PBS-4, but realized it was best to just start from the ground-up and develop a whole new cartridge and weapons to fire it.

That program became the 9x39 cartridge, with the VAL and VSS integrally-suppressed weapons chambering it.

338 Spectre and 338 ARC are more refined answers to this same problem, though the projectile selection for 9x39 has some interesting ones with brutal terminal effects.

 

[45-90]

I'm all in just ordered a reamer, go gauge., and barrel....start with 6.5 Twist, 5 twist available, also.
I had good luck with 6.5 twist in the 8.6 Blk.
Some of the current expanding copper subs are requiring 7 twist from Lehigh Defense, and 6.5 twist from Maker to open properly at sub velocities. That's not too important to me, but it might be to others...but I want it covered until the 338 ARC becomes popular enough to support a change in bullet design.
Depending when all the goodies get here should be able to machine it and put it together on a day or two.

 

[hseII]

Knowing the history & performance of the .338 Spectre,

Which twist will be the best for the .338 ARC?

1:7 or 1:6.5 or 1:5?

 

[rlsmith1]

How do these subs work when impacting bone? This whole discussion really has me hoping the 375 Raptor / 37 Creed becomes more mainstream (and kinda makes sense if Hornady wants to flip the bird to Q and continue to ignore the 8.6 BLK while putting even more energy on target)

ETA: a 35 Creed could be very interesting too

 

[st1650]

Knowing the history & performance of the .338 Spectre,

Which twist will be the best for the .338 ARC?

1:7 or 1:6.5 or 1:5?

1:7 is fine

https://makerbullets.com/proddetail.php?prod=338300SUBREX

 

[45-90]

I believe 1-7 to 1-5 is the best area. I chose 1 in 6.5 and it works, no blow ups on lead and I ran the 350 Maker to 1670 fps in the 8.6 with the 6.5 Twist and 200 gr lead Speer to over 2550 fps. No problems and accuracy was excellent.
But the copper bullet for the 3 twist should be on the 1100 fps instead of the 1000 fps threshold.
Maker has bullets for the 338 Spectre, which is almost the same as the 338 ARC and they are for 6.5 twist.
This pertains to those specific hunting bullets, the match bullets will be fine in the 8 twist down past -20° and zero altitude before becoming a unstable. Hornady has tested their 307 gr bullets so they should work. Twist rate Depends on the use of the weapon, and available bullet choice.

 

[TxWelder35]

be more interested if it had the 1:3 twist and shooting solids. That 1:3 twist makes those solids do ridiculous things that you can’t with lead jacketed bullets

 

[Ledzep]

be more interested if it had the 1:3 twist and shooting solids. That 1:3 twist makes those solids do ridiculous things that you can’t with lead jacketed bullets

I mean do whatever you think is best, but I've shot a lot of .308 and .338 bullets into gel over the last 5-6 years with various twist rates, and I design bullets for a living, and I'm not sold on the idea. From a bullet design perspective it absolutely shrinks the "success" envelope for terminal ballistics.

Is there a 5-10% total KE boost by doing so put into the in-flight bullet? Yes.

Does it transfer into the target? Maybe, but often not. You back yourself into a corner where only a few types/designs of (relatively) expensive monolithics work. Cup and core can't hold on. All for a 5-10% energy boost?

1:3" twist is the ONLY time I've ever seen a ELD-X bullet explode out of the muzzle and I know a guy personally that bought into the 8.6 thing and grenaded his can.

We saw the same thing when SIG went w/1:5" with the MCX, it degraded terminal performance (ripped off petals) and required the design of new purpose-built monolithic bullets in our TAP line of ammo. If the bullet sheds the petals, over penetrates, and the shank is still spinning fast as hell, what good is that KE doing you? The ammunition and the weapon have to jive, and IMO the negatives of the uber-fast twist rates easily outweigh whatever perceived benefits there are. YMMV.

 

[45-90]

be more interested if it had the 1:3 twist and shooting solids. That 1:3 twist makes those solids do ridiculous things that you can’t with lead jacketed bullets

I took off the 1-3 twist on the 8.6 and replaced with a 1-6.5. It was much better in every respect, along with no bullet blow ups.
But if you insist you can get a 1--3 twist... Go to Mos-Tek for a custom barrel 338 ARC, or 1-5 or 1-6.5 or 1-8.
Plus a bunch of other calibers like 358, .375, .400, 458, for the caliber and twist, you desire in many cases.
I considered their 5 twist for the 338 ARC, because it's mostly a sub gun...
But I will run bullets as light as 100 grs for supers in experiments in 6.5 twist.

MOS-TEK has SS blanks in stock in 3 and 5 twist, for those who chamber their own...or special order ready to install.

 

[TxWelder35]

I took off the 1-3 twist on the 8.6 and replaced with a 1-6.5. It was much better in every respect, along with no bullet blow ups.
But if you insist you can get a 1--3 twist... Go to Mos-Tek for a custom barrel 338 ARC, or 1-5 or 1-6.5 or 1-8.
Plus a bunch of other calibers like 358, .375, .400, 458, for the caliber and twist, you desire in many cases.
I considered their 5 twist for the 338 ARC, because it's mostly a sub gun...
But I will run bullets as light as 100 grs for supers in experiments in 6.5 twist.

MOS-TEK has SS blanks in stock in 3 and 5 twist, for those who chamber their own...or special order ready to install.

Lead and jacketed bullets don’t intrest me much in subs. 300blk has been underwhelming on making pigs hit and stick to the ground. Especially subs.

Buddy of mine got a 8.6. Solid coppers and fast twist makes the bullet do ridiculous things. Some live animal testing has showing it to be very promising.

The fast twist rate adds a whole other method of holding and delivering energy on target.

 

[45-90]

Lead and jacketed bullets don’t intrest me much in subs. 300blk has been underwhelming on making pigs hit and stick to the ground. Especially subs.

Buddy of mine got a 8.6. Solid coppers and fast twist makes the bullet do ridiculous things. Some live animal testing has showing it to be very promising.

The fast twist rate adds a whole other method of holding and delivering energy on target.

I had both the 3 twist and chose the 6.5 twist. For my use the 6.5 twist is totally versatile, the 3 twist is limited in usefulness. The 3 twist and any twist are limited to the laws of physics. Energy in equals energy out, it can not be created or destroyed...the fast twist looses more energy to heat in the forward movement due to fast rifling and will loose a bit of velicity, but gain in centrifical force. So the end energy is the same....minus heat, and friction loss. So one has a tiny bit more forward velocity and one has the difference in rotational energy....about the energy less than a sub sonic 22 short.
So the big difference is the bullet is about to come apart on impact ...depending on speed. The slower twist will get the same result at slightly higher velocity....but then you begin to get super sonic ...if that's important. The guys who make these bullets can change them physically to match the twist. They already make bullets for 6.5 Twist and 3 twist and state they are not interchangeable.
If the 8 twist becomes popular in the 338 ARC they will make copper hollow points for it ...just like they do in their pistol bullets, and other rifle bullets, in the slower twists.
But you can have the twist that you like in most any of these calibers as stated...
I'm a fan of what works for me...I'm already machining bullets for supers the 132 gr bore rider and 2 150 gr bullets.
Barnes hollow pointed, and a cut down Hornady copper. Checking the jacket thickness & construction of several bullets. So one can make bullets to fit your particular needs including sliting saw to slot into segments. A semi high velocity 338 ARC varminter? Or a 800 fps 100 gr rat gun that probably won't operate the bolt in an auto loader, but it cam be made to expand...inquiring minds want to know.

 

[The_Wizard]

8.6 b/o and 338 ARC are different and share enough similarities to justify having both….

1. Murica
2. Subs
3. Murica

 

[st1650]

338 ARC with a 6.5 tw would be a good balance for the SubX and the maker/lehigh expanding coppers

 

[45-90]

338 ARC with a 6.5 tw would be a good balance for the SubX and the maker/lehigh expanding coppers

Yes those expanding bullets, are already available for the 6.5 twist, at sub velocities. They have proven accuracy in my 8.6, 6.5 twist, for 350 gr Maker and the 300 gr match bullets, with no speed limit like the 3 twist, with blowup problems.
The new 6.5 twist barrel arrives tue, for the 338 ARC, hopefully the finish chamber reamer & go gauge are not far behind.
Probably have to make the brass and dies just to shoot it... they are slow getting those things to market...dates have already been pushed back on dies being available.

 

[st1650]

Anyone has the 8.6 BLK h20 case capacity? How close is it to 338 Fed ? Just trying to run some numbers off quickload

 

[45-90]

Anyone has the 8.6 BLK h20 case capacity? How close is it to 338 Fed ? Just trying to run some numbers off quickload

Use the 338 whisper 7 BR page , adjust case length, COAL, capacity, and bullet parameters. Those will be different, but not far off. Your H2O case capacity depends on the cases one selects or the brass they are formed out of. The 30-06, 308, 6.5 CM, or brand of new 8.6 Blkout cases.
3 twist loads in my experience topped out long before the 6.5 twist, like 3 grains of powder...but my early Faxon barrel was very rough rifling, which didn't help, and had to be lapped to be useful.
H20 capacity will very 46.4 gr for my CM cases, 47.3 gr for hybrid cases, less capacity for 30-06 cases.
H20 capacity of the 338 Federal is listed as 56.7 gr.
But the 338 Federal velocity can be equaled in a bolt gun and even surpassed in long heavy bullets with long barrel and hybrid cases, by using some of the extra pressure needed from the hybrid cases.
There are always compromises, and choices need to be made. What is your main purpose for the gun.
You can't get these velocities in a 3 twist and ya can't get them in a short barrel.
I play with subs but never intend to use them on a game animal.
A 200 gr bullet at 2570 fps or a 160 gr Barnes at 2800 fps out of my 8.6 bolt gun, would kill very well, and lots cheaper than Maker, but I play with Maker bullets, and Lehigh Defense bullets subs, & Close Quarters, 300 blkout over 2600 fps.
Plus make my own, like 30 Mauser 86 gr pistol bullets hollow pointed for small game.
I just relate what I do, those who can barrow from it, modify it, report on it, are welcome to do so.
The subs are limited, but supers are wide open to velocity and better accuracy if one chooses a slower twist, and a longer barrel.
If you want a short barrel and subs, you will not get full supper sonic potential, you'll be way behind on velocity, energy, & trajectory, especially with the lighter bullets.
But who cares about that at 75 yds or less if your sub bullets are performing.
Choices, and compromise, what do you want to accomplish.

 

[st1650]

Use the 338 whisper 7 BR page , adjust case length, COAL, capacity, and bullet parameters. Those will be different, but not far off. Your H2O case capacity depends on the cases one selects or the brass they are formed out of. The 30-06, 308, 6.5 CM, or brand of new 8.6 Blkout cases.
3 twist loads in my experience topped out long before the 6.5 twist, like 3 grains of powder...but my early Faxon barrel was very rough rifling, which didn't help, and had to be lapped to be useful.
H20 capacity will very 46.4 gr for my CM cases, 47.3 gr for hybrid cases, less capacity for 30-06 cases.
H20 capacity of the 338 Federal is listed as 56.7 gr.
But the 338 Federal velocity can be equaled in a bolt gun and even surpassed in long heavy bullets with long barrel and hybrid cases, by using some of the extra pressure needed from the hybrid cases.
There are always compromises, and choices need to be made. What is your main purpose for the gun.
You can't get these velocities in a 3 twist and ya can't get them in a short barrel.
I play with subs but never intend to use them on a game animal.
A 200 gr bullet at 2570 fps or a 160 gr Barnes at 2800 fps out of my 8.6 bolt gun, would kill very well, and lots cheaper than Maker, but I play with Maker bullets, and Lehigh Defense bullets subs, & Close Quarters, 300 blkout over 2600 fps.
Plus make my own, like 30 Mauser 86 gr pistol bullets hollow pointed for small game.
I just relate what I do, those who can barrow from it, modify it, report on it, are welcome to do so.
The subs are limited, but supers are wide open to velocity and better accuracy if one chooses a slower twist, and a longer barrel.
If you want a short barrel and subs, you will not get full supper sonic potential, you'll be way behind on velocity, energy, & trajectory, especially with the lighter bullets.
But who cares about that at 75 yds or less if your sub bullets are performing.
Choices, and compromise, what do you want to accomplish.

High IQ post, thanks mate.
Just about to pull the trigger on a ARC CDG prefit 12.5in 6.5 tw from MOS-TEK
I can find the Alpha brass semi locally
It'll be a dedicated subsonic to replace my 12.5in 300BLK anTI that I will be semi retiring.
I already got the 450BM for hunting but it's a heavy beast (DTA Gen2, 16in full 1.25in contour) and I'd like something a notch higher than 300BLK that the wife and kid can handle and I already have a spare ARC CDG SA with a 308 bolt face without a barrel.
I've had really good success with N32c for all my subs (300blk, 308win and 450BM) and that's what I'm planning to use for heavy subs 300-350 gr and I wanted to make sure I won't pressure out or bulk out. Seems like even a 350gr full copper should be able to reach 1000FPS out of a 12.5in according to Quickload (12.5gr N32c, 53K psi, 93% case fill)

 

[45-90]

High IQ post, thanks mate.
Just about to pull the trigger on a ARC CDG prefit 12.5in 6.5 tw from MOS-TEK
I can find the Alpha brass semi locally
It'll be a dedicated subsonic to replace my 12.5in 300BLK anTI that I will be semi retiring.
I already got the 450BM for hunting but it's a heavy beast (DTA Gen2, 16in full 1.25in contour) and I'd like something a notch higher than 300BLK that the wife and kid can handle and I already have a spare ARC CDG SA with a 308 bolt face without a barrel.
I've had really good success with N32c for all my subs (300blk, 308win and 450BM) and that's what I'm planning to use for heavy subs 300-350 gr and I wanted to make sure I won't pressure out or bulk out. Seems like even a 350gr full copper should be able to reach 1000FPS out of a 12.5in according to Quickload (12.5gr N32c, 53K psi, 93% case fill)

Those look like some sound choices for sucess. I didn't have any Tin Star bulky powder to try, but Red Dot is bulky.
Using QL as above I tested these powders, they may helpful as a backup plan.
Also the Lee Factory crimp die can be employed to help with velocity spreads...this will have to be checked with the powder you use.

These are 350 Maker loads for my 8.6 blkout 6.5 twist that may be helpful to your new barrel.
9 different powders fired at the same target from 51 yds lazered the 350 Maker was very accurate they tend to go through the same hole...If velocity is similar.

Also found some cheap 35 cent 272 gr fmj for accurate sub plinking, and post the pictures and loads.
For family fun with subs the 35 cent 272 gr bullets shipped to your door.
I fired 100 of em the first time out, and they can be used to get you into the sub velocity ball park instead of the expensive 350 Maker.

 

[LRRPF52]

For those wondering about hunting with subs, here’s a guy who shoots 570gr Lehighs from a 458 SOCOM bolt gun out to distances that are way beyond what I would have expected. Look at the blood mist from the deer upon impact-absolutely brutal:

 

[st1650]

Those look like some sound choices for sucess. I didn't have any Tin Star bulky powder to try, but Red Dot is bulky.
Using QL as above I tested these powders, they may helpful as a backup plan.
Also the Lee Factory crimp die can be employed to help with velocity spreads...this will have to be checked with the powder you use.

These are 350 Maker loads for my 8.6 blkout 6.5 twist that may be helpful to your new barrel.
9 different powders fired at the same target from 51 yds lazered the 350 Maker was very accurate they tend to go through the same hole...If velocity is similar.

Also found some cheap 35 cent 272 gr fmj for accurate sub plinking, and post the pictures and loads.
For family fun with subs the 35 cent 272 gr bullets shipped to your door.
I fired 100 of em the first time out, and they can be used to get you into the sub velocity ball park instead of the expensive 350 Maker.

Red dot is good, burns fast and quiet. Blue dot is good as well. I used blue dot in my 500gr cast 450bm with very low SDs and good accuracy.
Am I correct presuming that your experience was less than great with the 1/3 tw and that you have no problem stabilizing the 350 with the 1:6.5tw even though 1/3 is the “recommended” ?
I’ve heard light crimp helps with the Lehigh/maker bullets but I haven’t personally tried it yet.

 

[LRRPF52]

Looking through the different .338 cal cartridge performance classes, 338 ARC seems to be a 338 Marlin Express that fits in an AR-15. It should be a hammer both with supers and subs.

Could get interesting with purpose-built lower expansion threshold monoliths.

The other thing I like is you have high mag capacity with heavy-hitting loads. It will be interesting to see if mags need stronger springs like 300 Whisper does for the significantly-heavier cartridge stack once you start talking about 25-30rd mags.

@45-90 do you have any 25rd ASC Grendel or 30rd Geissele 6mm ARC/Grendel mags?

@Ledzep what capacity magazines did you guys test with the AR-15s? I know in the podcast that there was discussion about how well they fed and cycled, which surprised some of the people who shot them in ARs.

 

[hseII]

Red dot is good, burns fast and quiet. Blue dot is good as well. I used blue dot in my 500gr cast 450bm with very low SDs and good accuracy.
Am I correct presuming that your experience was less than great with the 1/3 tw and that you have no problem stabilizing the 350 with the 1:6.5tw even though 1/3 is the “recommended” ?
I’ve heard light crimp helps with the Lehigh/maker bullets but I haven’t personally tried it yet.

Our only hand load subs experience has been with Red dot in a .308 bolt gun.

It’s good enough for our plinking use.
I want to try it in the .338 ARC when components become available.

 

[45-90]

Red dot is good, burns fast and quiet. Blue dot is good as well. I used blue dot in my 500gr cast 450bm with very low SDs and good accuracy.
Am I correct presuming that your experience was less than great with the 1/3 tw and that you have no problem stabilizing the 350 with the 1:6.5tw even though 1/3 is the “recommended” ?
I’ve heard light crimp helps with the Lehigh/maker bullets but I haven’t personally tried it yet.

Yes the 1-6 twist stabilized the 350 Maker.
The 3 twist is not for me, I have scrapped mine for the 6.5 twist and will never return to a 3 twist for anything. It's too radical IMO, and leaves alot to be desired and unsafe. Get it a bit too fast and the bullets blow up inside your muzzle device as I have experienced, destroying hundreds of dollars worth of muzzle device and magneto speed bayonet.
Besides lead bullet blowup, copper petals blow off before they reach the target.
Early on guys running cans and 3 twist kept their muzzle velocities at 900 fps for best results.
Too limiting for me.

 

[45-90]

Looking through the different .338 cal cartridge performance classes, 338 ARC seems to be a 338 Marlin Express that fits in an AR-15. It should be a hammer both with supers and subs.

Could get interesting with purpose-built lower expansion threshold monoliths.

The other thing I like is you have high mag capacity with heavy-hitting loads. It will be interesting to see if mags need stronger springs like 300 Whisper does for the significantly-heavier cartridge stack once you start talking about 25-30rd mags.

@45-90 do you have any 25rd ASC Grendel or 30rd Geissele 6mm ARC/Grendel mags?

@Ledzep what capacity magazines did you guys test with the AR-15s? I know in the podcast that there was discussion about how well they fed and cycled, which surprised some of the people who shot them in ARs.

The tiny 338 ARC supers will not even be close to the velocity of the 338 Marlin as the 338 Marlin is a full sized but rimmed 6.5 CM, compared to a shortened 6 mm ARC. The Marlin express can stuff 40 to 50 grs of powdet in the case.
To complete with the 338 Marlin you'd need the 8.6 blk and hybrid cases, preferably a bolt gun.
I'm not a high capacity mag guy....I have a few but almost never use them.
Mine in common use, is where I prefer 10 rd mags.
I ain't in combat, or gaming and I don't do many mag dumps, much anymore, even with 223...but I'm capable just in case, it can run at 1085 rds per minute. Plus it can be changed to 9mm, 300 blk, for putting ammo down range.
Even in the 9mm I prefer my 17 round Glock to the 32 rd Glock mags, in the AR 15
Others want all the capacity they can get.
But 10 rounders are reliable and get it done for me.

 

[45-90]

For those wondering about hunting with subs, here’s a guy who shoots 570gr Lehighs from a 458 SOCOM bolt gun out to distances that are way beyond what I would have expected. Look at the blood mist from the deer upon impact-absolutely brutal:

Nothing brings energy like the 510 Whisper, for subs 750 gr Maker...1002 gr solid, 2600 ft / lbs at the muzzle at 1100 fps.
Military bullets that explode in impact begin to penetrate 3/8" armor plate if ya push the velocity or supers or subs for hunting elephant if your into that with 5000 ft/ lbs of energy on light supers. Bullets from 300 gr to 1002 gr.
I have a 16 twist bushmaster that I shoot 500 gr resized .458" subs, but some require faster twist in expanding copper to stablize or open at low velocity.
The 458 SOCOM sub is a good tool for sub hunting, but I personally an not into LR with it, or deer plinking.

 

[CaptNemo]

I think with subs, it's like drag racing engines. There's no replacement for displacement.
Electric nonsense excluded.

In Drag Racing, the only replacement for Cubic Inches is Rectangular Dollars.

 

[LRRPF52]

The tiny 338 ARC supers will not even be close to the velocity of the 338 Marlin as the 338 Marlin is a full sized but rimmed 6.5 CM, compared to a shortened 6 mm ARC. The Marlin express can stuff 40 to 50 grs of powdet in the case.
To complete with the 338 Marlin you'd need the 8.6 blk and hybrid cases, preferably a bolt gun.
I'm not a high capacity mag guy....I have a few but almost never use them.
Mine in common use, is where I prefer 10 rd mags.
I ain't in combat, or gaming and I don't do many mag dumps, much anymore, even with 223...but I'm capable just in case, it can run at 1085 rds per minute. Plus it can be changed to 9mm, 300 blk, for putting ammo down range.
Even in the 9mm I prefer my 17 round Glock to the 32 rd Glock mags, in the AR 15
Others want all the capacity they can get.
But 10 rounders are reliable and get it done for me.

I was looking at Hornady’s data for the .338 Marlin Express, and they’re showing a 200gr FTX at 2400fps from a 24” barrel out of a lever gun.

Hornady is saying 2075fps from a 16” barrel for the 175gr in 338 ARC.

When I drop the barrel length for that 200gr .338 Marlin down to 16”, it gives me 2232fps.

This is the closest of the legacy .338s I could find to 338 ARC performance, comparing Lever gun pressure to AR-15.

 

[45-90]

I was looking at Hornady’s data for the .338 Marlin Express, and they’re showing a 200gr FTX at 2400fps from a 24” barrel out of a lever gun.

Hornady is saying 2075fps from a 16” barrel for the 175gr in 338 ARC.

When I drop the barrel length for that 200gr .338 Marlin down to 16”, it gives me 2232fps.

This is the closest of the legacy .338s I could find to 338 ARC performance, comparing Lever gun pressure to AR-15.

It would be nice if that was the case....but your comparison is totally flawed.
Comparing a 200 gr to a short 175 gr you instantly gain back the 150 fps you lost in the Marlin cartridge by going from 24" to 16" barrel. So you're still 350 to 400 fps down in velocity.
Hornady produced light 338 bullets cause regular 338 bullets would be too long and intrude in the tiny powder space, for supers to even be effective at their designed velocity for hunting.
The 338 ARC is primarily just a subsonic cartridge.
I'm building a 338 ARC, the 6.5 twist barrel should arrive tomorrow, but the chamber reamer hasn't shipped.
Mocked up case, and machined some Hornady & Barnes copper bullets down to 150 gr and 132 gr bore riders to gain some velocity.
I do have some Hornady 200 gr flex tips for 338 Marlin that preform down to 1800 fps, but 1800 fps is probably about max at the muzzle for the 338 ARC and 200 gr...it may be as slow as 1600 fps, for the 16" barrel.
The 350 gr Maker may not even be able to be used....have to see if max velocities top out before expansion maybe as low as 600 to 800 fps. Soon we will know....