Reply with quote #1
I'am not new. but not old ether.
I'am looking for twist rates info for 6mm & 243 barrels.
the twist are 1 in 8,8.5,9,9.25,9.5,10,12.......
What is the Lightest,Best & Heaves Bullet Grain weight
For each barrel twist rates?
please do not give BAD or incret information
Reply with quote #2
You need to establish the
specific bullet length, weight and muzzle velocity (fps) and punch this into the Don Miller equation. You are looking for a gyroscopic stability factory in excess of 1.4.
Bryan Litz book contains all references you might need on this subject.
Reply with quote #3
If your looking for a compromise, a 1-9" twist will shoot the 95 VLDs well and the lighter 55gr bullets. I shoot the 105 Amaxes in my 243 ack imp and they work well.
Reply with quote #4
Here is one chart...
- 8" Special for VLD bullets over 100 gr.
- 8"* Ratchet rifled 4 groove
- 10" For bullets up to 120 gr. and VLD under 100 gr.
- 12" for bullets up to 85gr.
- 13"* for bullets up to 75gr.
- 14"* for bullets up to 70gr.
- 14"* Ratchet rifled 4 groove
- 15"* Special for bullets up to 70gr.
Reply with quote #5
I've owned more then one 9-1/4tw 27" factory 40x barrels chambered in 6mm Rem that shoot both 105gr and 55gr bullets equally well.
Reply with quote #6
My old 12" twist .244 Remington rifles were limited to lighter bullets, but the two newer 9" twist 6mm Remingtons are versatile. As RJ noted, they shoot everything from 105 A-Max and 95 VLD bullets to 55 grain Nosler BalTips. My 40-X with a Hart barrel shoots 58 grain Hornadys exceptionally well.
If you want to shoot 105 Berger VLD to 107 Sierra MK, you will need an 8" twist. IF you want to shoot the 115 Berger or DTAC, you will need a 7.8" or faster twist.
Reply with quote #7
So RJinTexas and sleepygator. 9-1/4" twist are the most versatile ove the 6mm&243 twist rates?
Reply with quote #8
As long as you do not want to shoot the heavy, long boattails like the Berger 105 and Sierra 107. Mine have a straight 9" twist. The heaviest that I can shoot is the Hornady 105 A-Max which seems a little easier to stabilize than others the same weight. It must be driven pretty hard.
If you do not care about the lightest (55 up to 70) bullets, go with the 8" so you can shoot the Sierra and Berger bullets. The light varmint bullets might have problems in 8" at .243 or 6mm velocities.