JJMoody
Well-Known Member
The most detrimental outcome between 8 and 9 twist in this case is overthinking which to get.
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MudRunner2005
Well-Known Member
Exactly. If you plan on going with any 7mm, just go ahead and get a 1:8.
Turnbolt53
Well-Known Member
Bullets are only getting longer, and they are much more concentric and better balanced than they used to be. Over-twisting a rifle isn't near the concern that it was in the old days.
Correct. Faster twist for the purpose of faster twist is not gain, in fact ^^^^ that happens. But we are talking about a 280AI and a 180gr long bearing surface bullet. With a 2800 fps velocity spinning at 252,000 rpm, that doesn't happen. For reference, at 9 twist , 242,000 rpm
FIGJAM
Well-Known Member
Plus I am anti-muzzle brake. My 300 rum give enough punishment. The 280 AI seems to be a sweet spot.
Lee Goodwin
Well-Known Member
Wish I could find a 280 or 280AI.
codyadams
Well-Known Member
I'll give an example of what it takes to "overtwist". In my .260 AI, I have an 8 twist. I usually shoot 140+ bullets in it. However, I fireformed some Peterson brass, and for fun and somewhat curiosity, I got some 85 grain sierra varminters, figured the extra twist would help the explosive affect. I loaded with varget, sent them at a mild 3350 fps. They grouped like this:
With the lower two of the group being from me yanking the trigger on both shots. HOWEVER, if my barrel got anything past warm, I would get every couple rounds as flyers, like 20 feet off, due to them coming apart.
But as you see, they were still very accurate, with zero load developement, they would just come apart. This is the extreme you have to go to to have twist cause a significant issue.
With the lower two of the group being from me yanking the trigger on both shots. HOWEVER, if my barrel got anything past warm, I would get every couple rounds as flyers, like 20 feet off, due to them coming apart.
But as you see, they were still very accurate, with zero load developement, they would just come apart. This is the extreme you have to go to to have twist cause a significant issue.
Lee Goodwin
Well-Known Member
Might as well buy a Browning hells canyon rifle already set up in 28N. Or just have a single shot rifle.?
MudRunner2005
Well-Known Member
Or start with a R700 donor rifle/action that was factory chambered in one of the RUM cartridges, and you're ready to go, other than blueprinting & building.
My go to chambering remains the .300 WM from antelope to elk size game (931 yards farthest thus far) up to 1K yards. Because the OP's purpose is ...
... TwoMore's .338 RUM above is a formidable choice especially when the majestic elk at 1200 yards is involved.
"My" unwritten rule is 1500 FT-LBS for elk and 1000 FT-LBS for deer at impact with consideration of the minimum velocity the bullet is designed for. There is no substitute for shot placement and displacement. The "NUT" behind the trigger remains the biggest factor.
The OP needs to process and synthesize all the information to make a sound decision, which sometimes that easy because we all have different "real-world" experiences, wants/needs, opinions, and personal preferences. For this reason, I never ask ... just build it, right or wrong, because it is not going to be my last.
Good luck to the OP. Cheers!
Canhunter35
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And the parameters given by the op are difficult to meet on a standard bolt face action, no matter any way you slice itMy go to chambering remains the .300 WM from antelope to elk size game (931 yards farthest thus far) up to 1K yards. Because the OP's purpose is ...
... TwoMore's .338 RUM above is a formidable choice especially when the majestic elk at 1200 yards is involved.
"My" unwritten rule is 1500 FT-LBS for elk and 1000 FT-LBS for deer at impact with consideration of the minimum velocity the bullet is designed for. There is no substitute for shot placement and displacement. The "NUT" behind the trigger remains the biggest factor.
The OP needs to process and synthesize all the information to make a sound decision, which sometimes that easy because we all have different "real-world" experiences, wants/needs, opinions, and personal preferences. For this reason, I never ask ... just build it, right or wrong, because it is not going to be my last.
Good luck to the OP. Cheers!
codyadams
Well-Known Member
This is true. In my opinion, there are zero factory options in a .280 AI, or any other standard bolt face offerings for that matter, that will have enough steam left at 1200 yds for an elk. Hand loads, doable, but you will be on the low end. But factory loads are a significant hindrance. There are some that will get you out there pretty far for sure, but 1200 is a poke on an elk.
FIGJAM
Well-Known Member
Just to clarify my original post - it was range work out to 1200. Then deer, elk and bears etc out to 800-900 yards. Looking back I could have worded that better.
Turnbolt53
Well-Known Member
Even better . . . . "deer, elk, black bears etc. out to whatever distance I feel comfortable"
