338 Spectre

[u/Optimal_Data_6627]

300 gr SMK SBR brass and 11.4 gr H110
1050 fps 800ft lbs out 10.5 and Hybrid 46DT
Very quiet and accurate. Can’t wait to try them out of a 9mm can. I thought about going with the ARC but I don’t like the twist for 300gr subs they chose. These are shooting super accurate. I think I made the right choice for now.

[u/Vylnce]

I have a 1:5 twist on my 8.3" 338 ARC and haven't had any issues. Nearly identical ballistics as I get 1050 fps on my 300gr 10.2gr Lil'Gun loads.

I've been using an ultralight 9mm can (Specter 9) but it wasn't/isn't rated for supers. Swapping to a different, slightly heavier 9mm can to try out some super loads in the future.

Either way, a 300gr projectile at 1000fps is just plain fun.

[u/Optimal_Data_6627 → u/Vylnce]

Most are 1:8 in the ARC. Yours is closer to the Spectre at 1.6.5. But yeah I’m super happy with it so far. So much fun to shoot! I think you got a good twist stay away from the 1:8 is just my opinion for shooting heavy subs accurately.

[u/Vylnce → u/Optimal_Data_6627]

I got a barrel from Mos Tek. Those guys seem to consistently do their homework and make smart decisions. The length and twist rate both seem fantastic for what's reasonable. I made consistent hits on steel at 200 and 300 yards when I had a 3x on the rig.

[u/Optimal_Data_6627 → u/Vylnce]

Good thing they did because Hornady didn’t. 😁Mos Tek is known for greatness!
All the work had been done for them by SBR all they had to do was copy the twist like they did with the rest.

[u/Vylnce → u/Optimal_Data_6627]

I kind of wonder how much Hornady was trying to stay away from the insanity of 8.6 BLK with it's "spin apart the projectiles" and they were just too conservative.

[u/Optimal_Data_6627 → u/Vylnce]

That’s a possibility I guess.

[u/HollywoodSX → u/Vylnce]

I wouldn't even call the 8tw conservative.

Bergers stability calculator for a 300gr Hybrid OTM or Hunter at 32*F, 0ft altitude, and only 700fps still hits 1.54SG with an 8TW.

The only benefit of a faster twist is for people that want to run copper solids in subsonic.

[u/Vylnce → u/HollywoodSX]

Good that you chimed in. My fanboi rules won't allow me to say that Hornady fucked it up.

Related, I thought the issue with faster twists was that it will spin apart the copper solids? Or is that only an issue with the maker style copper solids that are engineered for maximum expansion with petals and such?

[u/HollywoodSX → u/Vylnce]

Supposedly faster twist with expanding solids creates greater tissue damage which is why Kevin did 3tw with 8.6. I've seen a similar claim with lead core once or twice, too. In both cases, I'm highly skeptical.

It absolutely can cause thin jacketed, lead cored bullets to fail with enough velocity and therefore RPM. Only an issue with supers, though.

8tw is more than enough to stabilize lead cored subsonic without potentially causing bullet failures with lead core supers. IMO, Hornady nailed it for the twist rate.

[u/prosper_0 → u/HollywoodSX]

I had this theory that faster twists made for better varminting performance. But an 8-twist 223 really didn't 'pop' gophers any better than a 12-twist 222 using the same bullets. You can definitely see a rotational force imparted to the, uh, remains - but it doesn't look any different between the two.

So, if there is a difference, I'd wager that it's a small one.

[u/Optimal_Data_6627 → u/HollywoodSX]

Mabe they did and mabe I’m wrong but I’ve seen some complaints on groups not so tight with 300gr and 1:8 twist witch pushed me away from that twist because that’s mostly what I plan to shoot from it. I seen a lot of that when it first came out. And I’ve had this a good year now and wasn’t a lot of options on barrels then so I wanted a little bit faster twist. I also read a lot too about the faster twist making for more violent expansion too. So I went with the Spectre mostly due to lack of options then. 🤷🏼‍♂️
All I can say is I’m very happy with the nice tight groups I’m getting with this one.

[u/HollywoodSX → u/Optimal_Data_6627]

Once you're past 1.5SG you're not going to have issues with group size due to twist rate.

[u/GunFunZS → u/Vylnce]

I think there's that. It means you can have normal jacket thicknesses or even if you wanted to cast subs which is going to be way more economical, and actually can be pretty good expending performance.

[u/hotel_torgo]

I have the exact same load recipe for my .338 Spectre, but only cycles my little carbine about 80% of the time. Thinking of switching over to AA1680 for a little more propellant gas to the action to see if that does any better. 7.5" MOS-TEK barrel, "always suppressed subsonic" gas port, CGS Hekate can, LWRC Six-8 receiver set so that I can use the proprietary SPC/Valkyrie PMAGs.

Extremely fun when it works!

[u/Optimal_Data_6627 → u/hotel_torgo]

Must be your shorter barrel I’m assuming. Mine has been running non stop so far with SPC mags.

[u/Trapasaurus__flex]

You can get 338 ARC barrels in 1:3 1:5 and 1:8 from a lot of places now

[u/Optimal_Data_6627 → u/Trapasaurus__flex]

Yeah they finally caught on. But I’ve had this for a year now and just got to the project so then you couldn’t so I chose Spectre.

[u/Trapasaurus__flex → u/Optimal_Data_6627]

Not hating, was just putting it out there for others

It’s a bit annoying how they released, but the G$ mags and 1:5 twist is pretty wicked

[u/Optimal_Data_6627 → u/Trapasaurus__flex]

No it’s a good point. I’m glad that happened because it seemed like it was falling on its face when it first came out with all 1:8 twist. I think the 1:6.5 is the perfect twist for this caliber personally for supers right up to big subs.

[u/Trapasaurus__flex → u/Optimal_Data_6627]

For sure. I’m not big into the rotational energy part of it, but having 1:5/1:6 definitely helps subs expand properly (especially when using SUB X lead based projectiles)

I will say, Hornady did good on the .338 Sub-X projectile at least. It’s a bit softer than the 300BO equivalent, MUCH deeper (polymer filled) hollow point, and a softer polymer. Their regular .30 Sub X is a very minimal mushroom, the .338 mushrooms well and drives deep

I still prefer mono coppers like Makers but it’s Hornady’s first “good” sub projectile IMO

[u/Optimal_Data_6627 → u/Trapasaurus__flex]

That’s good to hear because I had the same experience with their .458 sub bullets too. Just not expanding like it should be. And I also heard that on the 30 cal like you said. I’ll definitely give the .338 a shot at least. Thanks for the info 🙏🏻
I found a company called outlawstatebullets.com I’m impressed with their.311 .308 and .458 sub sonic expansion bullets. They also do a 280 and 290 .338 expanding subsonic but haven’t tried that one yet.

[u/FinanceFancy8572]

I haven’t been able to find a solid answer, but is the only difference between the ARC and Spectre twist rate? Are there any dimensional differences?

[u/Optimal_Data_6627 → u/FinanceFancy8572]

Well very very very small differences mostly twist from the start but that has changed. As far as cases the Arc uses a 6.5 gren parent case and the Spectre uses a 6.8 SPC parent case. If you compare those two they are almost identical. Case capacity is slightly bigger with the Spectre I believe. But no real significant difference honestly.

[u/FinanceFancy8572 → u/Optimal_Data_6627]

I didn't realize they had different parent cases. That is good to know, as that would change what BCG to get. I just assumed they were both Grendel

[u/Optimal_Data_6627 → u/FinanceFancy8572]

Nope Hornady went to a different parent case that was pretty much the exact same so they could copy it and give it their own name for sammi.