Started some load development for the 338 ARC in Quickloads. Just waiting on a 10" 1:6.5 McGowen Precision Barrel and a full length sizing die from Hornady.
338 ARC Load Data
- Thread starter 6.5x61Super
- Start date
I've been shooting the 338 Spectre almost identical to the 338 ARC.
The slightly longer case on the right in the pic is the 338 ARC it appears to have a bit over a grain extra capacity, then tbe 338 Spectre case on the left.
So 338 Spectre load data would be very close to 338 ARC.
This is a 6.5 twist barrel 16" AR 15.
This is a very accurate AR 15 cartridge with low S/D in velocities with subs and supers.
I've fired most bullets from 160 gr Barnes to 350 gr Maker.
The two cartridges are almost twins with the new 338 ARC with a tiny bit more capacity, so this should get ya started... work up on super loads
The slightly longer case on the right in the pic is the 338 ARC it appears to have a bit over a grain extra capacity, then tbe 338 Spectre case on the left.
So 338 Spectre load data would be very close to 338 ARC.
This is a 6.5 twist barrel 16" AR 15.
This is a very accurate AR 15 cartridge with low S/D in velocities with subs and supers.
I've fired most bullets from 160 gr Barnes to 350 gr Maker.
The two cartridges are almost twins with the new 338 ARC with a tiny bit more capacity, so this should get ya started... work up on super loads
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Glad to see Lil Gun as a powder you chose. I have lots of it and a good amount of A1680. I figure both of those will be good Sub Load powders. I just hope Hornady hurries up and gets Dies, Bullets and Data out. The 307g SubX Bullets will be a necessity.
My Barrel is ordered in a bolt gun 16" barrel. I probably will not have it till September or October.
LilGun is much better than 1680 for the 338 Slectre/ 338 ARC.
lilGun gets higher velocities with a hundred percent burn with supers.
And cleaner, with 100% burn with most subs with 16" and shorter barrels.
Giving excellent accuracy and very low S/Ds in autos.
AA 1680 will decrease in efficiency with subs down to 85% burned, and almost never reach 100% burnt, in these small cases.
LilGun, then H110, or W296 are where you'll likely find the most consistent loads, with every bullet weight from 160 gr to 350 gr. Making powder selection easy.
Already tried 1680 very dirty with subs...will not use again.
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No, I resizesd 500 Starline 10 mag pistol cases very easily and cheap too but run 40,000 psi area...just spray and run through FL sizing die. No split necks.
They are good for subs and moderate loads. And are accurate with low velocity SDs.
Want an extra 100 fps or so in supers go to the factory 338 Spectre SR cases $46 per hundred ...or cut and form 224 Valkyrie brass for the higher pressure loads of supers, in the 55,000 psi area, and run the 165 gr Maker Super especially made for the 338 Spectre and its 6.5 twist at over 2100 fps in a 16" AR accurately, which is its maximum muzzle velocity...you'll have to test it to see if it expands at 900 fps...that would give one a fair amount of range, on a super load.
The 338 Spectre (and so should be the 338 ARC) is an excellent choice for the AR 15 builder shooting subs. Lighter, more accurate, and more consistent... easy to get to shoot small groups, when compared to the 8.6 blackout.
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338 Spectre from 224 Valkyrie is trim it to length, run through a 338 Spectre FL die, I turn the necks, and probably should anneal for longevity and consistency.
Not much to it.
I use a Bridgeport mill to trim to length in one second....but any case trimmer works.
Picture shows pretty much cut off neck and most of shoulder.
Not much to it.
I use a Bridgeport mill to trim to length in one second....but any case trimmer works.
Picture shows pretty much cut off neck and most of shoulder.
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Straight walled cases don’t get annealed, annealing the straight cases helps to prevent split necks when they are formed into shouldered cases. I have formed hundreds of Spectre cases from 10mm Mag and have yet to have one split on me, granted the 338S shoulder is a very mild transition in comparison to necking a 357 Max case down to .17 caliber.
That looks like the 450 bushmaster big bore barrel extension.
These are for feeding blunt or round nose bullets...which describes the Hornady 307 gr for the 338 ARC.
The 338 Spectre which is almost identical to the 338 ARC has a more traditional 300 blackout type barrel extension for pointed bullets. This works 100% for all pointed or semi pointed bullets, from 160 gr Barnes to 300 gr SMK or 300 gr match.
Haven't tried a 250 gr rd nose to see how it would feed. Something I'd need to check into before buying a thousand round nose bullets.
These are for feeding blunt or round nose bullets...which describes the Hornady 307 gr for the 338 ARC.
The 338 Spectre which is almost identical to the 338 ARC has a more traditional 300 blackout type barrel extension for pointed bullets. This works 100% for all pointed or semi pointed bullets, from 160 gr Barnes to 300 gr SMK or 300 gr match.
Haven't tried a 250 gr rd nose to see how it would feed. Something I'd need to check into before buying a thousand round nose bullets.
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