From an SME's perspective.
Fast vs. Slow Projectiles
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CrankyYankee
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If your goal is longer range performance... BC trumps speed. But for shorter limited ranges, speed trumps BC. (Strictly Exterior Ballistics).
That 40 grain bullet at 3400fps will drop less and be less effected by wind than the 80 grain until the 40 grain velocity drops off enough to where the higher BC of the 80 grain maintains its velocity better.
A varmint hunter who is limited to 300-400 yards MAY prefer the 40 grain at 3400fps. Personal preference.
JBM will show the intersection where the slower but higher BC bullet will stay "faster" than the 40 grain speedster.
The 62 grain Eld-vt going faster has replaced the 80 grain SMK going slower in my 223..... to 600 yards.
Thanks for the vid.
That 40 grain bullet at 3400fps will drop less and be less effected by wind than the 80 grain until the 40 grain velocity drops off enough to where the higher BC of the 80 grain maintains its velocity better.
A varmint hunter who is limited to 300-400 yards MAY prefer the 40 grain at 3400fps. Personal preference.
JBM will show the intersection where the slower but higher BC bullet will stay "faster" than the 40 grain speedster.
The 62 grain Eld-vt going faster has replaced the 80 grain SMK going slower in my 223..... to 600 yards.
Thanks for the vid.
Berger recommends a 1:9" or faster twist. The choice is yours to make. In my last four builds, I opted for the faster twist recommendation for the bullet I am going to use.
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I had a 10 twist that would not shoot the 165/175 class in a 270. Went 8 and it was happy happy.
Gary in MD
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Yea, but we've known this for decades…
jseandsje
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So I was kinda asking 2 different questions with one.
Yes - you're right I'd need a new barrel to shoot 170's.
But do I really need the barrel and 170? The 150 and 170 cross over in energy and wind drift at exactly 1000 yards. The velocity crossover around 1200.
So I don't really need the 170 and fast twist right? At least not in this case.
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The 150 Bergers did great in my 10 twist, to much further than I would be comfortable shooting game with them.
Now, I remember this conversation before. It boils down to your impact velocity and energy goals at 1200Y. If you are happy with your 150's performance, then no, you do not need the 170 or a faster twist barrel.
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Not to mention the versatile bullet performance of the ABLR. It will smash bone AND expand, wrecking framework along with organs, plumbing and wiring. Hard to ignore the capability. The BC is pretty dang good…also.
jseandsje
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I think I'm gonna have to get a barrel. I'm very curious what a 170 c&c or 155 LRX will do in a long action 270wsm.
If you've been in a short action with your .270 I'd say you will make some gains to offset the heavier weight and faster twist. Useful, there.
It entirely depends the distance you are hunting. I ask folks wanting a new barrel what are the distances of your last ten kills? Then realistically what distance do you see your kills in text five years.
I have one 270 WSM and think it's GREAT cartridge in a longer barrel properly chambered. It's at its hunting best with 140 to 150gr bullets IMHO. 7mm's rule with the 168 to 180gr bullets, long distance hunting, so I always recommend moving up in bullet diameter——this for hunting which for me mean bullets that reliably stop game under the various and sometimes extreme conditions / circumstances.
In video example remember the heavy 22 bullet launched at 2600 will make a 1200 yards but will barely mark a steel target. Fun shooting but most of us hunt/kill stuff.
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