Does rate of twist = your bullet weight ?

I was talking to another reloader the other day and he said he based his bullet weight on his barrel rate of twist. Therefore he shoots 62 grain bullets through his 22-250. Any thoughts on this?

the rate of twist is very important to bullet stabilization. My .223 has a 1:9 twist and will not shoot anything lighter than 62gr some people say they have great luck with lighter bullets but I don't. I wouldn't have believed it either until i proved it to myself ... it matters a whole lot.

OK, so is there a formula or chart to figure out rate of twist and bullet weights ?

yes there is ... I dont know what it is but i use my Corbin twist rate calculator. Tell me what you got and i'll run it for ya

http://kwk.us/twist.html

this looks pretty good

I've got a Remington 30.06 it's about 16 years old, I don't know the twist rate.

While certain twist rates do call for certain weight bullets, there is a lot that plays into it. And I for one am like Reload30-06, don't believe it until its proven. I have a couple loads that shouldn't work in rifles due to twist, but they do.

A good read to understanding twist rates and more
http://en.wikipedia.org/wiki/Rifling

Here is an online calculator for the Greenhill Formula
http://kwk.us/twist.html

the easiest way to find out what it is is to put a mark on a cleaning rod at the muzzle of your barrel. pull it out when it makes one complete turn put another mark in the rod ... measure between the marks you have rate of twist.

brow_tines wrote:I've got a Remington 30.06 it's about 16 years old, I don't know the twist rate.

Search google you might find something.

There are also methods you can do to determine, fairly accuately, your twist rate. Both Ammosmith and IraqVeteran8888 have videos demonstrating the procedure.

Reload3006 wrote:http://kwk.us/twist.html

this looks pretty good

Reload3006 wrote:the easiest way to find out what it is is to put a mark on a cleaning rod at the muzzle of your barrel. pull it out when it makes one complete turn put another mark in the rod ... measure between the marks you have rate of twist.

Geez Reload, I can't finish typing my message with the same info and you've already got it posted beating me to the punch

GMTA lol

Your Remington is more then likely a 1/10 twist. I have a .223 with a 1/8 twist rate but it seems to shoot lighter bullets (45-55) better then some of heavier weight bullets that match the twist rate.

RemMan700 wrote:Your Remington is more then likely a 1/10 twist.

That's what I was thinking I will make sure tomorrow, I'm at work now.

this is very generic, but easy to understand.

1. faster twist rate = heavier bullet (longer)and/or slower speeds

2. slower twist rate = lighter bullets(shorter) and/or faster speeds

It's not just about weight....it's also about the length!

note: pistol calibers tend to react differently, so this is mainly for rifle calibers.

Take for example a 60gr bullet fired from a 223 may require a 1-9" twist and the same bullet fired from a 22-250 needs a 1-14" twist. Why the huge difference in twist rates for the same bullet? Answer: SPEED

The 22-250 is launching the 60gr bullet at higher velocities than the 223, so less twist is required to stabilize the bullet. Both the 22-250 and 223 will put close to the same rotational rpm on the bullet but at different velocities.

OK LIGHT BULB moment !!!!!!

Yes I tend to have brain farts and I'm gonna post it.

The calculator at http://kwk.us/twist.html works really good if you remember it's the BULLET LENGTH and NOT the OAL of the cartridge.

1. So, what you have to do, is get your hands on different weights of bullets and then measure the length of each.

2. Then go to your favorite load data, it will give you a approximate muzzle velocity range for that bullet.

3. Now you have the proper numbers to plug into the calculator.

Please tell me if this looks correct now, I only wanted to reply to this again to try and help someones else out, that is/was having trouble.

I'm not so sure I agree with that calculator. I put in all the info for a run of the mill 69gr SMK and it kicked out 1-10.5" twist is recommended when in all reality 1-9" and faster work best.

it comes close....so I guess if you pick the next available twist that is faster than what the calculator gives you, you should be good.

Example: It kicks out 1-8.6"....better go with a 1-8", not a 1-9"

Most manufactures list the bullet lengths in their data....sometimes it's even on the box.

hawcer wrote:I'm not so sure I agree with that calculator. I put in all the info for a run of the mill 69gr SMK and it kicked out 1-10.5" twist is recommended when in all reality 1-9" and faster work best.

it comes close....so I guess if you pick the next available twist that is faster than what the calculator gives you, you should be good.

Example: It kicks out 1-8.6"....better go with a 1-8", not a 1-9"

Most manufactures list the bullet lengths in their data....sometimes it's even on the box.

Is the SMK bullet a boat tail if so try the length from the tip to the bevel of the boat tail (a bullet comparator helps with this) I use the twist calculator on Nosler 168gr and it was a lot different .

That jumps it up to around 1-12" twist....which is waaaay off.

That's not good. So now were back to if it shoots well don't over work the why. LOL

Its pretty much right on. :-)

I found this calculator to add to the mix. play with the fps # 2800 and above or 2799 and below and it will be a lot different because the constant in the formula changes from 150 to 180.


Oops fogot to add the link.

http://www.realguns.com/calculators/riflingtwist.html

XbonesX wrote: I have a couple loads that shouldn't work in rifles due to twist, but they do.

Are the bullets that work well that should not Hornady? The reason I ask is that seems to be the case in my Savage model 16 in .223 with a 1 in 9 twist. That is this gun:
http://www.savagearms.com/firearms/model/16FCSS

It shoots the 69 grain fine but I could not get good accuracy from lighter bullets like 53 or 55 grains. Except Hornady. It seems to like the lighter Hornady bullet are ok but no other lighter bullets.

EdgarEg wrote:

XbonesX wrote: I have a couple loads that shouldn't work in rifles due to twist, but they do.

Are the bullets that work well that should not Hornady? The reason I ask is that seems to be the case in my Savage model 16 in .223 with a 1 in 9 twist. That is this gun:
http://www.savagearms.com/firearms/model/16FCSS

It shoots the 69 grain fine but I could not get good accuracy from lighter bullets like 53 or 55 grains. Except Hornady. It seems to like the lighter Hornady bullet ok but no other lighter bullets.

actually what really counts is the length of the bullet that contacts the rifling. So generally a heavier bullet will be longer It stands to reason that it would have to be because it cant get larger in diameter. Ok so the slight twist that comes to play here is the Ojive radius. a bullet with a blunt nose will give more rifling contact .but can be a shorter bullet .. A bullet with the same weight can be much longer with a sharper Ojive but less rifling contact. In general the heavier bullets will fly better in faster twist barrels but this doesn't exactly tell the whole story. Most Arms manufacturers try to strike a happy medium with their barrels so that their guns will work acceptably with a wide range of bullets in a given caliber. But you will find a certain weight and type of bullet that your gun happens to like and IMO barrel twist has a big part to play in that. But Speed also plays a factor you can shoot a lighter bullet slower and probably get good results.

EdgarEg wrote:

XbonesX wrote: I have a couple loads that shouldn't work in rifles due to twist, but they do.

Are the bullets that work well that should not Hornady? The reason I ask is that seems to be the case in my Savage model 16 in .223 with a 1 in 9 twist. That is this gun:
http://www.savagearms.com/firearms/model/16FCSS

It shoots the 69 grain fine but I could not get good accuracy from lighter bullets like 53 or 55 grains. Except Hornady. It seems to like the lighter Hornady bullet are ok but no other lighter bullets.

This seems to be the case with my Savage....I really need to test these in my DPMS 1-9" 24" upper and compare.

I get the same size(dime sized) groups as 69gr SMK's or Nosler cust comps with 52gr Hornady A-max's. They also have the same POI with out any scope adjustments @ 100 yards. The 52 gr Amax bullets are the Boat tail type and are designed for the 22-250, but work very well in my 223.

So far accuracy sucks with anything else lighter than 60gr.

Rate of twist is one of those things that seems like it should be hard science with set rules but does not work that way.

My Rock River 24" 1-8 5.56 loves 69 and 75 gr SMKs, and hates anything under 60 gr.

My 1-12 24" 22-250 loves 35-45 gr Nosler and Hornady varmit grenades.

My 1-14 28" 22 Cheetah Mk1 loves the light stuff in the low to mid 40s but will also for some reason toss the 69 - 75 SMKs well within 1 MOA. I can hold under 3" groups at 300 yards easy with this barrel. Not sure why, the specs say it should not shoot anything above 50 gr well.

My 26" 1-8.5 6.5-284 barrel loves the 120 - 140 gr SMKs and most hunting bullets in that weight range. Only the Speer Grand Slams and Barnes TSX in the 160 does it shoot well. Accuracy is fair with 150s and poor with 160s other than the Speer and Barnes TSX. My brother calls my 6.5-284 a boring gun to shoot because it will group 3/4" all day at 100 yards with my favorite load of either a Barnes 160 gr TSX or a Hornady SST 140 gr and 52.6 gr of R22 or 52 gr of 4831SC.