Thread: Fussy 243.

Greetings All.
Some notes on the 6mm cartridges.
After everything settled down after WW2 and the Korean conflict it was a good time for some new cartridges. Warren Page had been trying to persuade both Remington and Winchester to produce a 6mm cartridge based on a case around the .308 Win or .257 Roberts. He didn't get much responce but later found that both were working on a cartridge. Winchester were thinking of a varmint to deer cartridge and used a 1 in 10" twist on their .243 while Remington were thinking more of a varmint cartridge and went with 1 in 12" in their .244. Big mistake. The .244 tanked in the market and increasing the twist to 1 in 9" plus renaming it the 6mm Remington didn't help. The 6mm Remington is arguably a better cartridge with slightly better performance and load ability but it is gone.
The Brits had brought out a whole bunch of .240 cartridges in the 1920's including one just like the 6mm Remington and one like the 240 Weatherby but these seem to have gone as well.
Now there are heaps of new 6mm cartridges so we will have to see how that turns out.
Regards Grandpamac.

Think I’ve got some factory 100 grain Hornady interlock rounds left lying around I’ll bring them next weekend.

The 100gr Hornady Interlocks will work great in the Howa - I've used them a lot.

87 gr hornady v max shot well in every 243 I've owned, cheers.
But may not be suitable for your application??

Originally Posted by Micky Duck

Round nose heavy for calibre rule supreme up close.... I do recall 100grn .243 round nose being a thing a few years back...

There are heavier than that.
Geco do a 105, don't know if it's a RN
Have seen a 110gr for sale in the past.
Would imagine it would getting close to a RN for that weight

Originally Posted by TARGEX

Out of interest for anyone reading all this it is not bullet weight that decides required twist rate but bullet length!
if there was a heavy enough core material available I could make a 200gr bullet that would stabilise in a 6mm 10" twist barrel as long as the finished bullet length was short enough.
This is also the reason that plastic tip bullets in various calibers wont stabilise as the bullet LENGTH can exceed the barrel twist even though the bullet weight is supposed to work.
Hope this makes sense.
Cheers.

In the 1850s this was figured out by a bloke called green hill who came up with a formula to calculate the twist rate needed for any bullet length or alternately the longest bullet that will work with a given twist. It completely ignores weight . It also takes into account the projectile speed as as a bullet slows it's rotational speed slows and gyroscopic stability decreases. Which explains the occasional I'm on target at 100 yds but can't hit the target at 200. I know I've been there.

So working on that theory...if a trebly will stabilise a 70 grn Speer happily.anything shorter should work fine??? Trimming a long hollow nose back to the magic length should see it now stable??

Originally Posted by Marty Henry

In the 1850s this was figured out by a bloke called green hill who came up with a formula to calculate the twist rate needed for any bullet length or alternately the longest bullet that will work with a given twist. It completely ignores weight . It also takes into account the projectile speed as as a bullet slows it's rotational speed slows and gyroscopic stability decreases. Which explains the occasional I'm on target at 100 yds but can't hit the target at 200. I know I've been there.

Actually the opposite is true, rpm degrades much less quickly than velocity....so bullets on the verge of stability wobble there way out untill velocity has dropped enough that the rpm will hold them stable.