Hunter
Chasin' the Sunset
My shooting buddy has a Savage (with the target Accu-Trigger, which has a fairly-light pull) .223 with a 7-twist barrel and a three-inch wide flat forearm that he shoots free-recoil. When he shoots 80 gr bullets (off of a front rest that has “dog ears” on both sides of the forearm pad and weighs about 17 lbs.) the muzzle “jumps” WAY off the target to the right during recoil; however, when he shoots the same gun with a 9-twist barrel and a 53 grain bullet the muzzle doesn’t “jump” to the right near as much.
He also has a Savage (with the target Accu-Trigger) 6BR with a 12-twist barrel and a three-inch wide flat forearm that he shoots free-recoil, and when he shoots 70 gr bullets (off of a front rest that has "dog ears" on both sides of the forearm pad and weighs over 30 lbs.) the muzzle also “jumps” to the right – but not as much as the aforementioned 7-twist .223.
All three barrels are right twist and he makes an effort to be sure his rear bag is properly aligned with the front rest.
He thinks the torque imparted by the bullet’s rotation is what causes the “jump” – and I think I’ve read several places that suggest he’s correct. However, I don’t understand that theory so I asked someone who I thought might understand the matter (and he confirmed that he did understand it); his answer was that the torque was not the cause of the “jump” – but he didn’t say what was the cause; nor do I recall that he give a reason for his statement.
The reason I don’t understand the torque theory related to the muzzle moving sideways on recoil is because it seems to me that any torque imparted from a right spinning bullet (as viewed from the chamber and focusing on the 12:00 position on the bullet) would be offset by the fact that the bullet is also rotating LEFT (as viewed from the chamber and focusing on the 6:00 position on the bullet); thus, it seems to me that the two rotations would cancel out the effect of the other rotation.
Can someone shed some understanding on:
a. what causes the muzzle “jump” described above;
b. if it is torque from the bullet’s rotation, please explain why the “left-rotation” (as mentioned in my fifth paragraph above) does not off-set the right-rotation; and
c. would your answers be different if the gun was a custom gun?
He also has a Savage (with the target Accu-Trigger) 6BR with a 12-twist barrel and a three-inch wide flat forearm that he shoots free-recoil, and when he shoots 70 gr bullets (off of a front rest that has "dog ears" on both sides of the forearm pad and weighs over 30 lbs.) the muzzle also “jumps” to the right – but not as much as the aforementioned 7-twist .223.
All three barrels are right twist and he makes an effort to be sure his rear bag is properly aligned with the front rest.
He thinks the torque imparted by the bullet’s rotation is what causes the “jump” – and I think I’ve read several places that suggest he’s correct. However, I don’t understand that theory so I asked someone who I thought might understand the matter (and he confirmed that he did understand it); his answer was that the torque was not the cause of the “jump” – but he didn’t say what was the cause; nor do I recall that he give a reason for his statement.
The reason I don’t understand the torque theory related to the muzzle moving sideways on recoil is because it seems to me that any torque imparted from a right spinning bullet (as viewed from the chamber and focusing on the 12:00 position on the bullet) would be offset by the fact that the bullet is also rotating LEFT (as viewed from the chamber and focusing on the 6:00 position on the bullet); thus, it seems to me that the two rotations would cancel out the effect of the other rotation.
Can someone shed some understanding on:
a. what causes the muzzle “jump” described above;
b. if it is torque from the bullet’s rotation, please explain why the “left-rotation” (as mentioned in my fifth paragraph above) does not off-set the right-rotation; and
c. would your answers be different if the gun was a custom gun?
