All,
I realize that we have beat this twist rate thing to death for the 35 Whelen. I also realize much of the posts have been anidotal in nature.

My exact question for the mathaticians out there is will a 275 gr Hornady RN effectivly stablize in my 1:14 twist Shilen barrel?

Out of this rifle I have obtained some very decent groups of 3/4" and better at 100 yards, the holes all appear to be perfect circles. Will this bullet maintain adequate stability out to say 200 yards? What is the maximum weight that a 1:14 whelen is expected to properly stablize?

Muzzle velocity out of the 22" barrl is 2350 fps. If there is further information required to properly calculate stability, I will provide it.

Thank you for your help.

should,i can stabilize a 255 outta my 12 twist 358.

lamar,
as the bullet's weight and length go up, there's more room for the inadequicy of under-stabilization from too slow a twist than there is room for over-stabilization from too fast a twist of a lighter, shorter bullet.
bigbullet,
if your getting decent grups at 100 yrds with that twist, chances are it will work at longer distance because the rate of twist does not dwindle as velocity falls of, in fact the opposite occurs,...as velocity drops the rate the dynamic effect of twist increases because the tare of twist doesn't reduce. ie., the bullet is actually getting spun faster in relation to it's velocity as it slows down, sodynamic stability should increase.

BigBullet,
Would you mind sharing your load for the 275 Hornady RN?
regards,
Fury01

Google is a wonderful thing,
http://www.nfa.ca/content/view/132/197/
This link takes you to a bullet stability worksheet, just need to plug in the variables and a lot of good info is spat out.

We have been kicking around twist rates on the 35 Whelen a few times and what I have found is its all a bunch of whooy. The worksheet indicates that the minimum(maximum) twist rate required to fully stabibize a 310 grain bullet (the heaviest I know of for this caliber) is something like 1:22 inches. So all this discussion about weather 1:12 or 1:14, or 1:16 is best, no good or otherwise has been strictly opinion. The fact of the matter is that all the currect production rifles will stabilize the heaviest bullets available.

Fury, My load for the 275 gr Hornady RN is 56.0 grains of Reloader 15, in my 22" 1903 Springfield. For a long time I played with slower burning powders, like IMR 4350 and H414, but could not get tot he velocity I wanted. This powder works great in both my 35 Whelens. In my Remington CDL with its very long throat I can put an additional grain of powder; with this load and the longer barrel I get 2417 fps.These loads are max in my rifles, you know the rest.

So,if anyone has 275 grain Hornady RN that will not stabiblize in your rifle I will be happy to take them off your hands

Here is another link http://www.realguns.com/calc/riflingtwist

I was looking for the Greener formula which is a manual type formula for paper and pencil but too much eco type green in the searches these days.

I didn't want to edit the post as this may take a while. It is the Greenhill Formula for calculating rifling twist.



Greenhill Formula for Rifling Twists from Engel Ballistic Research

The Time-honored Greenhill formula was originally used for determining twist rates in the new rifled artillery in the 19th Century.. It is important to note that it is projectile *length*, not *weight* which is the determining factor when considering the best twist rate for your intended use. Weight can vary for a specific bullet length from use of different material and also is determined to some degree by projectile shape. Often long-range match shooters utilizing low drag or VLD projectiles will voice a preference for "lazy" twists; i.e. just enough to stabilize the bullet. The requirements of a Shooter who is utilizing both high velocity and Subsonic ammunition are quite different.

When utilizing subsonic ammunition there is another factor to take into consideration. The projectile not only has only (about) 1/3 of the forward velocity of standard ammunition in Rifle calibers, it also has 1/3 of the *rotational* velocity...think "RPM's". This makes for a less gyroscopically-stable projectile, so a faster rate of twist is indicated than by simply applying Greenhill alone. This wisdom was imparted to me in a conversation with the great barrel-maker Boots Obermeyer. It makes perfect sense, and doubly so coming from him, so we'll take it as Gospel.

Greenhill Formula For Rifling Twists

T*B=150*Sqrt (Density of Lead/Density of Bullet)

T=Twist

B= Bullet length

Both units have to be in 'Calibers', density portion is optional

**********

To determine the *approximate* twist rate for a given projectile (this varies a bit by shape):

Using the a 190 gr Sierra MatchKing bullet #2210M (.,30 cal) as an example. If we measure the bullet's length it is 1.375" long .

B=Bullet length in *Calibers* (Length/Diameter), hence 1.375/0.308= 4.46 *calibers* long

From formula we have T=150/4.46=33.6. This figure is now in *calibers*, so we convert the twist from calibers to inches. So T=33.6 x 0.308=10.34".

This is why most commercial rifles in .300 Win. Magnum come with a 1:10" twist barrel.

***********

One can go further and get involved in formulas for density, but for most conventional lead/gilding metal projectiles, the above will suffice. Note that this is for a normal High Velocity loading. Subsonics generally require a somewhat faster twist rate. If one plans to use both High Velocity and Subsonic loads in the same platform, a good compromise which works acceptably for both must be found. If the platform is a "dedicated" gun in which subsonic ammunition alone will be used, then a faster rate can be utilized in order to be able to accurately shoot longer (and thus heavier) projectiles subsonically and with good accuracy.

Example:

Twist rates for 7.62mm/.308:

High Velocity only: 1:11-1/8" to 1:12"
Both: 1:10"
Subsonic ONLY: 1:8"

Bear in mind that "dedicated" back at the shop might not be "dedicated" in the field. Most knowledgeable end users prefer to have the option of utilizing both loads so as to be able to address changing tactical requirements on the spot

somehow i missed putting in the velocity value for that 255 [cast] in my 358.
it stabilizes for me from 1200 up to 2300.

Good for you BigBullet!...

I have seen guys post that a 1:16 won't even stabilize a 250gr. bullet...They still don't clue in even when you point out them that Remington who legitimized the .35 Whelen from wildcat status to factory round and sells their .35 Whelen chambered rifles with a 1:16 twist also sells factory ammo loaded with 250gr bullets..

Went to the Horny web sight and could find no 35 cal. 275gr. bullet. What's the haps? roger

bartsche,
Discontinued many moons ago. The boxes I have are very old, maybe 20 years. I beleive these are actually fairly heavily constructed, maybe for the 358 Norma Mag type velocity, they keep going out the back of my bullet box of wet news.

Thanks BigBullet, good to know these things. Trying heavier bullets than 250 gr is something I have not done yet, but since I have been thinking of selling my 375 it may be a good idea. Not that I would need them, still nice to know what your limitations are. I will probably skip straight to the 310 gr Woodleighs.

How was the recoil with 275 gr buillets and a stiff load of powder?

Raybass,
Compared to our 225 gr TSX loads, the recoil is definately greater. This conclusion is based upon my Pachmyer recoil pad-o-meter. When shooting from the bench the 225 grain are sort of like a heavy 30-06, but with 250 grain bullets and heavier the recoil pad bottoms out and I can really feel it. Of course when shooting from normal hunting positions the recoil is very controllable and still significantly less then my 338 Win Mag which is what I alway compare it to, as these rifle fit the same catagory at least for me.

The 35 Whelen is pushing similar weight bullets within 150 fps, with 16-18 grains of less powder, you would expect less recoil, but my Whelens are both about 2 pounds lighter then my 338 Win Mag.

Hope this helps,

I can really tell the difference when shooting heavy 250 gr loads, easier on the shoulder than the 375 H&H with 300 gr loads though. I did try some 200 gr hornady's the other day, recoil was pretty light compared to the 250's and 225's.

BigBullet got me going on the 225 gr TSX's and RL-15 load for my whelen, if you haven't tried it you should ,very accurate.

The deciding factor is the length of that bullet, expressed IN CALIBERS.......

El Deguello,
Yes it is bullet length and not the weight that is the critical factor. When we talk about heavier bullets the length of the bullet is typically longer, but not always. So your point about the length is important.

quote:

Originally posted by BigBullet:
The worksheet indicates that the minimum(maximum) twist rate required to fully stabibize a 310 grain bullet (the heaviest I know of for this caliber) is something like 1:22 inches. So all this discussion about weather 1:12 or 1:14, or 1:16 is best, no good or otherwise has been strictly opinion.

I wish my rifles read internet sites ... the Woodleigh 310gr soft will not stabilise in a 1:14" from a 358Win (approx. 2000fps) at 100m, will show tipping from a 1:16" 35Whelen (approx. 2200fps) at 200 (2 shots out of 5), and are fine as far as I can hit the paper from my 350RemMag Ruger with 1:12". Finn Aaggard reported similar findings when he wrote his test of the Rem700 in 35Whelen. Problems dont appear at the shorter ranges ... then again whether you should be shooting at 200m plus with a 310gr is also a valid point!! Best thing to do is test your rifle at the ranges you require it to work.
Cheers...
Con

Who knows for sure till they test them in their gun. I know I would not be shooting a 310 gr a longer distances. 100-150 yrds would be tops