You'd think not, but it took forever to get 6 ARC brass as a component when it came out... Supply chains and whatnot back then, but still.
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338 ARC
- Thread starter Parham4020
- Start date
The Berger stability calculator uses the miller formula which is not intended for subsonic speed. It’s useless for that application according to Litz. I have not tried the 250 gr SMK or the Scenar/Lockbase, but I have tried to cut down the 300 gr SMK in the lathe. I chopped off 6mm of the tip, ending up with a bullet that looks like Hornady subX in the front.
At this point they make round holes again. Here at 100 meters
And here at 190 meters
I hope Hornady have tested the 338 Sub X thoroughly in 8 twist with Doppler radar before thy released it? Litz says subsonic flight is not yet fully understood, so I guess it’s all trial and error. I have examples of solids from Peregrine bullets that won’t fly straight in 7 twist that Peregrine says are stable in 9 and 8 twist.
All this .338 arc talk made me order a 300 blk barrel and superlative arms gas block. Oops
10 mm mag brass is available I just bought 500 rds, and formed it, and so is SBR SR brass.
The 10 mag brass has been great for subs and really cheap. So I'll use it for subs and moderate loads. The SR SBR brass appears to have a bit more strength so far, and is less than half price of Hornady.
Hornady has not been great brass either and I avoid it as much as possible. So you're right none of this brass is Lapua but it will do, for the intended purpose of the round, mostly subs. Mine is very accurate with a variety of reloads, especially 300 gr SMK.
The 165 gr Maker super expanding bullet hit 2100 fps for a super load along with cheap 200 gr Speer at subs to 1900 fps with SR brass. The pistol brass will not make 1900 fps more than once, so 1750 or maybe 1800 fps would be a good max for it.
So I'm finding out what this brass will handle. May try some cut down 224 Valkyrie brass to see how it works for supers. But for subs the pistol brass works fine...so far in my experience.
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I think that you may have to allow that this could be a "your mileage may vary" type of thing because my subsonic load is less than 9gr of Lil Gun with 300gr Makers and one firing of that load significantly weakened the primer pockets on the large pistol primer pockets SBR brass that I have. I don't think I could load it a third time in that brass.
I checked the primer pockets on all these loads they appear as new after 1 firing with subs, and moderate loads, where they are giving excellent accuracy, with pistol primers, then checked the next batch from 2 days ago...all is good on the first loading, 300 gr SMK, 300 gr Maker, 272 gr FMJ plus a bunch of 200 gr Speer.
Out of all the loads I tried I lost 6 cases with too much case expansion on top loads with both primers
Like the 165 gr Maker at 2136 fps one was too loose and the others were a one shot more with the no go gauge, with the SR.
I noticed no case head expansion at all when miked at the case head, with AA 1680 cases came out very sooty as powder gas came back along the case toward the shooter...even felt it.
But velocity was still 1160 fps with the 200 gr Speer. It had large velocity variations and less accuracy...not the powder for light 200 gr subs.
Not very efficient here but I haven't tried it with the 300 gr bullets where it's lower pressure may help you with primer pockets, and the extra bullet weight will help build pressure for a better burn.
I have 50 338 ARC cases coming to check them against the 338 Spectre, for capacity and strength...most likely about equal, but I'll find out.
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Since I have 224 Valkyrie and 6.5 Grendel cases lying around....I decided to make 338 Spectre cases out of them.
The 224 Valkyrie is easy, trim to length, lube, & run through the 338 spectre FL die.
The 6.5 Grendel is a bit more involved for the average reloader.
Cut to length. Turn the sold head to size, blend out and recut extractor groove, lube, size in the FL 338 Spectre die.
Anneal and resize. It goes pretty quick with a lathe once set up.
So the 224 Valkyrie is really easy.
Both chamber in the rifle at the same die setting as the 338 Spectre brass.
For what it's worth, pressures jump pretty fast in this tiny case, so even tougher, harder case headed brass, might not increase velocity much but hang in there longer for a few more firings.
The 224 Valkyrie is easy, trim to length, lube, & run through the 338 spectre FL die.
The 6.5 Grendel is a bit more involved for the average reloader.
Cut to length. Turn the sold head to size, blend out and recut extractor groove, lube, size in the FL 338 Spectre die.
Anneal and resize. It goes pretty quick with a lathe once set up.
So the 224 Valkyrie is really easy.
Both chamber in the rifle at the same die setting as the 338 Spectre brass.
For what it's worth, pressures jump pretty fast in this tiny case, so even tougher, harder case headed brass, might not increase velocity much but hang in there longer for a few more firings.
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The 338 ARC and the 338 Spectre are almost identical, as I suspected earlier.
I jumped on the Spectre to check out these small cased 338s while waiting for 338 ARC reamer, brass etc.
Well the 338 ARC brass arrived, so let's compare it to the 338 Spectre I now have been shooting is very accurate.
Hornady brass is $104 per hundred, Spectra brass is $46 per hundres for SR primer or a bit cheeper for LP primered cases.
Here they are side by side.
The 338 Spectre holds 29.4 grs of H2O,
The 338 ARC holds 30.5 grs of H2O, probably increase a grain when fired, depending on chamber.
Maybe the ARC will have 25 to 40 fps more velocity with supers...but the difference is insignificant...but with good barrels the ARC should be accurate.
The Spectre has been around a long time over 10 yrs I believe.
The Spectre has a 6.5 twist and I have fired bullets from 160 to 350 grs in it.
Hornady has an 8 twist, that may make a difference with the long heavy 300 gr match bullets at sub velocities. Maker already makes a variety of sub and super expanding bullets for the 6.5 twist.
Their 165 gr super expanding is running 2100 fps in the Spectre 16" barrel and supposed expand around as low as 900 fps.
I jumped on the Spectre to check out these small cased 338s while waiting for 338 ARC reamer, brass etc.
Well the 338 ARC brass arrived, so let's compare it to the 338 Spectre I now have been shooting is very accurate.
Hornady brass is $104 per hundred, Spectra brass is $46 per hundres for SR primer or a bit cheeper for LP primered cases.
Here they are side by side.
The 338 Spectre holds 29.4 grs of H2O,
The 338 ARC holds 30.5 grs of H2O, probably increase a grain when fired, depending on chamber.
Maybe the ARC will have 25 to 40 fps more velocity with supers...but the difference is insignificant...but with good barrels the ARC should be accurate.
The Spectre has been around a long time over 10 yrs I believe.
The Spectre has a 6.5 twist and I have fired bullets from 160 to 350 grs in it.
Hornady has an 8 twist, that may make a difference with the long heavy 300 gr match bullets at sub velocities. Maker already makes a variety of sub and super expanding bullets for the 6.5 twist.
Their 165 gr super expanding is running 2100 fps in the Spectre 16" barrel and supposed expand around as low as 900 fps.
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I've wanted to see a NAS3 case for the 6arc for some velocity gains. With the 6 arc gaining steam that could be a future possibility and converting it to 338 arc wouldn’t be too much trouble.
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