I am building a new predator hunting rifle and it will have an 18" barrel shooting light 58-75gr projectiles. It will be ran with a suppressor. I was going to chamber it in 6 Creedmoor but also considering 6xc and 6 GT. I started wondering if I would be losing much velocity with going to a 6GT over a 6 Creedmoor in that short of a barrel. Would the extra case capacity of the Creedmoor gain me anything over the GT with such a short barrel and light projectiles? Does anyone shoot a combination like this? If so what are your velocities?
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Which 6mm for 18" barrel?
- Thread starter 6.5grendel
- Start date
There’s a pretty kick ass deal in the classifieds here for an 18” dasher that I keep eyeballing. May be worth a look. Just @ you so you can check it out.
I was hoping to get around 3550fps with a 65gr or around 3400 with a 75gr with the 18" barrel and suppressor. Would the 6GT be capable of those numbers?
Thank you! That really helps give me an idea of what's capable. Looks like I'll have to go with the Creedmoor or XC to get close to the numbers I was wanting. Thank you for taking the time to run those numbers. I really appreciate it.
If you only plan to run light bullets and you aren’t already reloading for any of the other 6mm’s mentioned you might think about a 243. At least there are some factory options for 58 and 75 grain v max ammo from Hornady. I realize this was posted in the reloading section so I am sure you plan to run reloads but sometimes it’s nice to have ammo options when life happens. Not aware of any factory loads for the 6 creed with bullets lighter than the 87 v max.
No problem - just ping me if you want me to run numbers for a specific cartridge/bullet/powder combo.
Given your screen name I figured it makes sense to point this out - a 6 ARC or its various 6mm Grendel wildcat predecessors and a good load of Leverevolution will come real close to that, and in a smaller frame than a Creedmoor. You might need a 20" barrel, or sacrifice a little velocity, etc, but it's right there in the ballpark. Obviously that'd dependent on using Leverevolution powder though; you won't get there with 4895, Varget, etc.
And you didn't say if you're thinking of a bolt gun or an AR. If it's a bolt gun the .473" case head is a lot simpler to set up and something like a Dasher or GT or even 6x47L makes more sense.
Also just for reference, and to follow up on my comment above, one of my 243 LBC (a 6 ARC predecessor, just a 6mm Grendel) AR15s is a 19" shooting that same 95gr VLD at 2,800 fps. (Not making that up - same velocity as yours.) It takes 3" more barrel to get there, and a load of Leverevolution powder; I'm guessing your load is with a stick powder of some sort.
This one also does the 90gr TGK at 3,000 fps (give up 100 fps if you prefer the 90gr ELD) and the 70gr TNT at 3,225 fps - not quite the 3,400 mentioned above but not too far off either. Case life is good in my rifles with all of these loads, meaning 10+ loads per case.
I would consider the 6mm ARC with an 18" barrel, both of mine are very accurate, but I shoot 108 gr bullets in mine.
The 6 Dasher was tested with light bullets, 55 over 4000 fps 58 gr 4100 fps 70 gr over 3700 fps and accurate with a 7.5 twist with especially the 58 gr... But it has a 28" barrel.
The 6 Dasher was tested with light bullets, 55 over 4000 fps 58 gr 4100 fps 70 gr over 3700 fps and accurate with a 7.5 twist with especially the 58 gr... But it has a 28" barrel.
I get 3500 w/ 58 gr VMAX in my 18” 6 ARC with 32.5 A2230. Mild pressure ejector swipe on the case though. I backed down to 32.3.
It is an incredibly accurate barrel with those VMAX. The barrel is for sale in the PX if you’re ever interested. I upgraded to a Proof CF, but in my very initial phases haven’t seen the accuracy of that barrel with other heavier rounds. Haven’t tried 58s because they’re a different powder. Also just starting to work up loads for it so I’ll stay optimistic about spending 2.5x as much
It is an incredibly accurate barrel with those VMAX. The barrel is for sale in the PX if you’re ever interested. I upgraded to a Proof CF, but in my very initial phases haven’t seen the accuracy of that barrel with other heavier rounds. Haven’t tried 58s because they’re a different powder. Also just starting to work up loads for it so I’ll stay optimistic about spending 2.5x as much
6Max is SPECIFICALLY designed for the AR15. It uses a 350 Legend mag (as it is the parent case) to get the 2.3 length according to the info on their website.
Any ASC stainless mag will handle that OAL; doesn’t have to be a 350 Legend mag specifically. I’m sure 5.56 ASC SS mags would work well too.
But yeah, the max is obviously designed to fit the AR15. Not sure why some would be trying to use CBTO measurements to determine if it fits anyway; that’s the wrong metric.
ah so someone reused the name of an existing sherman wildcat
well if a 6MAX (the original from sherman...and what most people would assume when you see a Max or Mega) has a 2.2-2.3" cbto and magnum boltface it isn't fitting in an AR15
What part of 350 LEGEND parent case do you refuse to read and comprehend??????
what fucking part of 6MAX was a Sherman cartridge way before this 350 legend shit do you not understand
6MAX (Sherman)makes the sales volume of 6.5 SAUM look like 22LR. Next, let's all die on a hill about DPMS AR10's not being an AR10 because they aren't Armalite.
Well this is a thread about achieving higher velocity than a 6CM is capable of...so going down in case volume is definitely the way to go
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OP velocity number hopes
Your unreadable garbage that doesn't come close to hitting what he wants from a 24" barrel let alone chop 6" and 150fps off
I ended up going with the 6 Creedmoor. I was afraid of not getting the numbers i was looking for with any of the others with a 18" barrel so I played it safe. I've had the barrel for a while now and so far have worked the 75 vmax's up to 3475 fps and 65 vmax's up to 3575 fps without pressure signs. I went a little higher than that with both projectiles but started getting pressure signs. I'm glad I went with the Creedmoor but I might have been just as happy with a GT, XC, 243, 243AI, etc. This is flat and fast like I was wanting. Should be trying it out on the coyotes this weekend finally.
I am using Rl16 under the 87 V-Max in my 18" 6 Creed and getting 3230. They hit coyotes pretty hard.
My point was more about using CBTO measurements to determine if something fits in a magazine. It's just the wrong measurement when the constraint is OAL. I'd hope that all but the newest reloaders realize that OAL of a specific CBTO measurement can vary by a lot depending on the bullet used; could be anything from a blunt protected point or even cast flat point up to a long pointy match bullet like an RDF or VLD.
But I'd bet that very few people (definitely not most) have every heard of the 6mm Sherman Max, while the new 6mm Max cartridge for the AR15 is all over the internet and gun rags lately. It wouldn't be my choice of round, but it's getting plenty of press right now so I'm pretty sure most people here understood what was being discussed.
my point was more than 2.2-2.3" CBTO regardless of bullet isn't really going to fit in an AR15. like it's so not even close to fitting i can make that reference
i'd bet more people on this forum know about Sherman than the 'new hotness' in the AR15 world. and when in a thread about fast 6mm's i'd be expecting someone to reference something that's actually fast, not a gun rag fudd flavor of the month that does nothing new
try a 6X45 you'll never look back hits hard they stay dead and its a wildcat as for brass any necked up 223 works mine are tack drivers, from 52 - 105 grain any bullet i like Hornaday and Nosler
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