Undertanding Barrell Twist Rates

[HappyGA]

I am a newbie. As you can see by my post count. Yes, I searched the site, found a couple of threads talking about it, but they were vague and people started arguing about what is right and what is wrong. All other search results were people asking what twist rate should I use. I am trying to understand what twist rate does and what is is most efficient on, so down the road I can help add to this forum, and not just be another question asker (which I will still be for the for-seeable future)

I have a Savage 10-FCP HS that I purchased and I am putting in the time researching a lot about how to run this gun efficiently.

I will be signing up for the online training very soon. (have to finish a project at home, so I have time to actually watch and practice what is being explained)

I am trying to understand barrell twist rate and what is most efficient. I noticed that for heavier bullets, the twist rate goes down. like a 1:10 for a 208Amax versus a 1:12 for a 175 smk. Am i correct when thinking the twist rate is dropping or am i reading the twist rate incorrectly?

I do not load my own ammo. Thanks in advance for all information provided.

 

[Wylie Custom]

Re: Undertanding Barrell Twist Rates

Check out this link and it will help you with proper twist:

http://www.shilen.com/calibersAndTwists.html

 

[DMann]

Re: Undertanding Barrell Twist Rates

The short answer is that twist rate is the rate of spin imparted to a bullet by the spiral rifling inside the barrel. Through trial and error, the Greenwood formula and other voodoo, several "standard" twist rates have been found within a certain caliber to be most efficient with a certain weight and configuration of projectile. The best rule of thumb is that a heavy-for-caliber projectile with a high ballistic coefficient will require a faster (lower numbers) spin to stabilize the projectile at maximum range.

There are numerous permutations of this basic concept, but that is the basic concept. It is possible to choose a specific twist to shoot bullets of a specific weight and configuration if that is what you plan to do. It is possible to find a twist that stabilizes several bullet weights and configurations pretty well in case you plan on shooting different bullets and loads.

Bryan Litz is a rocket scientist who can explain this much better than I. Read the two articles on "Understanding Long Range Bullets" here: http://www.appliedballisticsllc.com/Articles.htm to get you started.

 

[HappyGA]

Re: Undertanding Barrell Twist Rates

Thank you gentlemen for the information. I just printed it off, and will be reading over it tonight after i get done cutting a couple of loads of firewood.