team tractor Posted June 1, 2014 Report Share Posted June 1, 2014 I'm looking at getting a 223 for foxy and maybe munty if they breed a little more . My question is about twist rates. I've seen anywhere from 1-8 to 1-14 What's it all about ? I know what it is but what does it affect ? If I don't home load and use anything from 40-55 gr rounds would it matter? Quote Link to comment Share on other sites More sharing options...
team tractor Posted June 1, 2014 Author Report Share Posted June 1, 2014 Ok doh I found something on google perfect to my question so I might as well share. Twist Rates The .223 Rem shoots a wide range of bullets very effectively, from 35gr flat-based varmint bullets, to ultra-long 90gr VLDs. However, you'll need the right twist rate for your choice of bullet. For max velocity and accuracy with the lightest bullets, a 1:14" twist may be ideal. More versatile is a 1:12" twist that will allow you to shoot the popular 60-64 grain match bullets. (However, a 1:9" twist is needed for the steel-core 62gr bullet used in the M855 military loads, because that bullet is as long as most 70-grainers.) For normal lead-core jacketed bullets, a 1:9" twist will let you shoot up to 73gr bullets. Since most .223 Rem shooters prefer bullets in the 50-73gr range, a good "do-it-all" solution is a 9-twist, unless you're a Highpower competitor. For long-range match purposes, long, high-BC bullets are favored for their ability to buck the wind. You'll want at least a 1:8" twist to shoot the 77gr and 80gr MatchKings and 80gr Bergers. To shoot the new 90gr pills, a 1:6.5" is recommended, though a true 1:7" will work in most conditions. Overall, what twist rate is best? For varminting we like a 12-twist. The slower twist will give you a bit more velocity, and minimize the risk of jacket failure at high rpms. For general use, an 8-twist barrel will let you shoot the excellent 77gr and 80gr Sierra MatchKings and nearly all varieties of non-tracer milsurp ammo. We'd only select a 1:7" or faster twist barrel if we had a need to shoot the 90gr VLDs. Barrel Twist Rate 1:14" 1:12" 1:9" 1:8" 1:7" or 1:6.5" Max Bullet Weight 55gr FB 65gr FB 73gr BT 80gr BT 90gr BT VLD Acknowledgements: Big thanks to Andy ("Graymist") for his load data and many hours spent measuring brass, Quote Link to comment Share on other sites More sharing options...
bornfree Posted June 2, 2014 Report Share Posted June 2, 2014 1-12 works well for standard 55g factory ammo. Quote Link to comment Share on other sites More sharing options...
CharlieT Posted June 2, 2014 Report Share Posted June 2, 2014 (edited) That must be from the 6mmbr site ! Edited June 2, 2014 by CharlieT Quote Link to comment Share on other sites More sharing options...
wymberley Posted June 3, 2014 Report Share Posted June 3, 2014 As a rule of thumb, the twist rate (TR) can be calculated by:- TR = 3.5 (a constant) x square root of V (muzzle velocity) x D (bullet diameter) squared Length (of bullet) Quote Link to comment Share on other sites More sharing options...
Kes Posted June 3, 2014 Report Share Posted June 3, 2014 fo.r all models of e.g. Remington 700 e.g. VLS its listed under the specifications section - mine is as stated 1 in 12. Slower for more velocity, better lower bullet weights but up to maybe 60grains, so that includes Munjac etc. Also allows me to shoot heavier match bullets. Quote Link to comment Share on other sites More sharing options...
Amazed Posted June 3, 2014 Report Share Posted June 3, 2014 That must be from the 6mmbr site ! Ia good write up was it done by graymist originally ? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.