Twist rate in the 300 Whisper barrel

[Joe Kool]

What is the rate of twist in the factory T/C 300 Whisper barrels? I know that T/C used a 1 in 14" twist in their early 30 caliber barrels, and a 1 in 10" twist in their later barrels. The 300 Whisper is meant to shoot 220 gr. match bullets at sub-sonic velocity, is the twist faster than 1 in 10" to stabilize the long 220 gr. bullet?  

[RWD]

Joe, T/C's factory twist rate is 1-10. It will not stabilize the big bullets. SSK's are 1-8, and they will work .

[Joe Kool]

Thank you. I read the post about shooting deer with 300 Whisper sub sonic loads, and developed a 1060 fps.load for my 30/06, with Red Dot and a 220 gr cast bullet, Lyman #311284. It shoots great. A cast  bullet will stabilize with a slower twist rate then it takes to stablize a jacketed bullet of the same weight. I have a 10", 30 Herrett barrel with a 1 in 10" twist, that I'm going to try to develop a sub sonic load for. I just wanted to know  if T/C used a faster twist in their 300 Whisper barrels.  

[Bug]

That's something that mystified me. With all the hype about proprietary cartridges, and copywrighted names, why was T/C authorized to produce a barrel with the Whisper name, but in the wrong twist? It kinda bastardizes the whole concept of the Whisper. It was created to shoot heavy bullets, at subsonic velocities. If you're not gonna use the 200-220gr bullets, why not go with the .30-30, or .30 Herrett? Brass is cheaper, easier to get, and they are, arguably, ballistically superior.

 Re: Joe Kool: " A cast bullet will stabilize with a slower twist rate then it takes to stablize a jacketed bullet of the same weight".
Joe, I'd sure be curious to know how you arrived at this conclusion. I'm not argueing with the thought now, Just wanna know your reasoning.

[Joe Kool]

Bug, I think I read  an article in Handloader magazine about twist rate, that said a cast bullet will stabilize with a slower twist then it takes to stabilize a jacketed bullet. I've read it in a few other places, over the years. The factor is not the weight of the bullet but the length. A good example is a 223 with a 1 in 14" twist, will stabilize a 55 gr flat base bullet , but not the 55gr., M193 equivalent, full metal jacket boat tail. Both bullets are the same weight but the fmj is longer because of the boat tail and the thicker full metal jacket. Cast bullets have no jacket, so a cast bullet is shorter then a jacketed bullet of the same weight. Most cast bullets are round nose, flat nose, or the spitzer nose is blut, making them shorter, for the weight. In my experience with cast bullets, a 30/30 that will not stabilize a 170 gr jacketed bullet at 1400 fps will stalibize a 170 gr.cast bullet a 1200 fps.
 This afternoon, I tested the 220 gr cast bullets in the 30 Herrett, at sub sonic velicities. A charge of Red Dot got the velocity to 1050 fps., but the bullets were not stable. 3 out of 10 would tumble. I used my lathe to shorten the bullet's nose, and a file to put an ogive back on the nose. The weight was reduced to 205 gr. The shortened bullets were stable, and penetrated straight into the cardboard. I'm going to order a Lee 200 gr. bullet mould. I'll have to give up a little bullet weight for stability.  

[Kurt Heckman]

One of the reasons I went with the 300 whisper instead of 30 30 is because 30 is not legal for deer in Illinois unless it's pistol and you can only use bottle necks that the cases are 1.4 inches or less and must be factory published ballistics. I have some 220 grain subsonics but have yet to shoot them from what I have seen so far in IL most are using 125-150 grain on deer though and not subsonic. Kurt