Question: 223 loads:

wingman · May 14, 2010, 10:01 AM

Two rifles in 223, both set to shoot 1 inch high @ 100 yards both guns average .550 or less, and both shoot the same point on target with various loads except for the Sierra 69 Matchking, one prints 1 inch high while the other always impacts 3 inches right and low. Groups remain about same.

Barrels are both 1:9 twist, of course some difference is always expected I'm somewhat puzzled by such a large difference, perhaps someone with more knowledge can explain.

mjm · May 14, 2010, 10:18 AM

Are the barrel lengths different? If so what are the barrel lengths?

wingman · May 14, 2010, 10:36 AM

Quote:

Are the barrel lengths different? If so what are the barrel lengths?

Sorry I needed to state that, both Savage rifles, one a heavy barrel 26 inch the other a Varmint weight barrel 24 inch, the 26 inch is the problem with the 69gr matchking.

mjm · May 14, 2010, 11:54 AM

Thanks! The reason I asked was something I picked up reading about Optimum Charge Weight at:http://optimalchargeweight.embarqspace.com/# which said the following:

"Engineer Chris Long's model of barrel behavior suggests (simply put, and in part) that the initial shock wave, generated by the powder charge's ignition, travels at the speed of sound in steel (about 18.000 fps) from the chamber to the muzzle, then back, in a repeated pattern. When this wave is present at the muzzle, there is naturally much turbulence and obturation of the
"roundness" of the bore at the muzzle. However, when this main shock wave has reverberated back to the chamber end, the muzzle is relatively stable. This window of opportunity, according to Chris, is the best time for the bullet to exit the muzzle. The barrel is basically straight, and relatively calm."

If this is true, this might explain what you are dealing with.

wingman · May 14, 2010, 12:28 PM

Excellent link, I think I will try a 70gr flat based bullet see how it compares in both rifles, if it shoots consistent in both guns then perhaps it's linked to the design of the 69gr BT.

May 14, 2010, 10:01 AM	#1
wingman Senior Member Join Date: August 20, 2002 Posts: 2,108	Question: 223 loads: Two rifles in 223, both set to shoot 1 inch high @ 100 yards both guns average .550 or less, and both shoot the same point on target with various loads except for the Sierra 69 Matchking, one prints 1 inch high while the other always impacts 3 inches right and low. Groups remain about same. Barrels are both 1:9 twist, of course some difference is always expected I'm somewhat puzzled by such a large difference, perhaps someone with more knowledge can explain.

May 14, 2010, 10:18 AM	#2
mjm Member Join Date: October 14, 2009 Posts: 84	Are the barrel lengths different? If so what are the barrel lengths?

May 14, 2010, 11:54 AM	#4
mjm Member Join Date: October 14, 2009 Posts: 84	Thanks! The reason I asked was something I picked up reading about Optimum Charge Weight at:http://optimalchargeweight.embarqspace.com/# which said the following: "Engineer Chris Long's model of barrel behavior suggests (simply put, and in part) that the initial shock wave, generated by the powder charge's ignition, travels at the speed of sound in steel (about 18.000 fps) from the chamber to the muzzle, then back, in a repeated pattern. When this wave is present at the muzzle, there is naturally much turbulence and obturation of the "roundness" of the bore at the muzzle. However, when this main shock wave has reverberated back to the chamber end, the muzzle is relatively stable. This window of opportunity, according to Chris, is the best time for the bullet to exit the muzzle. The barrel is basically straight, and relatively calm." If this is true, this might explain what you are dealing with.

May 14, 2010, 12:28 PM	#5
wingman Senior Member Join Date: August 20, 2002 Posts: 2,108	Excellent link, I think I will try a 70gr flat based bullet see how it compares in both rifles, if it shoots consistent in both guns then perhaps it's linked to the design of the 69gr BT.