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T3X 300WM and 7mm Rem Mag Twist Rates
Maybe someone can shed some light on Tikka's twist rtes for me. I've been looking at two different chamberings in a Tikka Varmint but both rifles seem to have somewhat unorthodox twist rates.
1. 300 Win Mag 1:11 – Based on my reading, and not experience, you need a 1:10 to stabilize a wide range projectiles. I would expect to only get stability out of lighter weight bullets (increased stability at higher temps and altitudes)
2. 7mm Rem Mag 1:9.5 – Based on my reading, and not experience, you need a 1:9 or 1:9.25 to stabilize a wide range projectiles. I would expect to only get stability out of lighter weight bullets (increased stability at higher temps and altitudes)
The other concern I have is the Tikka Varmints come in a 23.7″ barrel, (the T3x Lite is in a 24.3″ barrel) where others (websites) seem to suggest that a 26″ is required for no velocity sacrifice) so what kind of muzzle velocity am I going to sacrifice with the 23.7″ barrel?
I absolutely love the Tikka product (I currently own two T3X Lite models in 30-06 and 6.5CM) so I am not knocking them at all but more looking for others experience and knowledge on this. I am not a reloader so would be limited to factory ammo. I want to ensure that I don't purchase something without fully understanding what I am buying and it's potential limitations.
So I guess my questions are:
Which is the overall better chambering based on twist rate, barrel length and muzzle velocity/stability?Thanks
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4 Replies
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My .300 Win Mag seems to like 200 gr. bullets pretty well, but they're not the heaviest for caliber by any means.
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You are correct!
The 1:11 twist of the 30 calibers are somewhat limiting.
I have a 30-06 with an 11 twist and I don’t load over 185 grns
If I had a stock 300 WM I’d keep the Bullet weight below 200 grns.
Same is true for the 7mm
Keep the bullets lighter, maybe 160 max which will perform well. The 7mm heavies will not shoot well. -
Thx. Kind of what I was expecting.
What are your thoughts on muzzle velocity? Most of my reading suggests a 26” barrel for both the 7mm mag and the 300 win mag yet Tikka is running a 24.3” in their standard rifle and a 23.7” in the Varmint.
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Muzzle velocity will impact stability. Faster mv = faster spin for a given twist. The issue is the distance you intend to shoot I believe. Spin rate decays over time and atmospheric conditions make a big difference in stability. Find one of Brian litz’s books on ballistics and read up. He is a good writer and knowledgeable.
Good shooting!
Ps. Barrel length is irrelevant, it’s about velocity. Longer barrels allow higher velocity to a point due to more complete burning of powder, but 3000 fps in a 24” barrel = 3000 fps in a 28” barrel as far as exterior ballistics are concerned.
Pps you are correct btw higher velocity for a given twist will let you shoot a longer Bullet stabilly
Meaning if you shoot a 200 grain 30 cal at sea level at 2500 fps it might not stabilize, but at 3000 fps it might.
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