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123 Nosler CC in M96 problem

Posted: Thu Mar 01, 2018 12:21 pm
by polaris
I have been using the Nosler 123 CC for 200 yard match shooting over IMR 4064. Don't remember the charge weight offhand, but it's up near the safe max pressure for the M96 per Hodgedon/IMR data, so it's stepping along pretty well. Fantastic accuracy, low recoil, zeroes well to my sights at 200... but hold on!

In a match last summer, I had 3 bullets fail to make the target. 1 in rapid prone, 1 slow prone sighter, 1 slow prone for record. No impact on sand impact berm or front cover berm noted by the pits. My scorer thought he heard an odd "crackle" and a puff of smoke at about the 125 yard mark. They were definitely not misses, scored 178-9x on the 18 rounds that did make the target, I call my misses well, and these were in the black when the trigger broke. The only conclusion I can draw is that the bullets were rotationally separating between 100-200 yards. Emailed Nosler, and they said this should not happen, they've tested this bullet at 6.5x284 velocities in a similar rate of twist.

Conditions were warm and humid, and the barrel was quite warm from repeated firing. Fired a match in slightly cooler conditions, as well as several at 100 yards with no issues. Wondering if anyone else has had this happen with lighter bullets in the M96?

Cost me a strong match win against a very competitive field, I'm going back to the Hornady 140 BTHP. Have probably put 1000 of them past 200 yards without any going POOF!

Re: 123 Nosler CC in M96 problem

Posted: Mon Feb 25, 2019 4:55 am
by Lumberjack
I have had problems With 108grain Lapua scenar in my swedish mauser. one of five bullets gets away from the othes, makes what would be a 1/2 moa Group Three times bigger.

Re: 123 Nosler CC in M96 problem

Posted: Mon Feb 25, 2019 9:40 am
by Rapidrob
Bullet is coming apart in the air, i would drop the load down as it reads like the bullet is going too fast for the rifling twist. A slower burning powder will help as well.

Re: 123 Nosler CC in M96 problem

Posted: Mon Feb 25, 2019 11:05 am
by slowbob2
The problem is a tight bore , not groove . A 96 Swede with a very tight bore , some are as small as .253 , with tear the jacket on a thin jacketed .264 bullet . Going to a .263 dia bullet or a thicker jacket should cure the problem .

Re: 123 Nosler CC in M96 problem

Posted: Mon Feb 25, 2019 9:10 pm
by ammolab
slowbob2 wrote: Mon Feb 25, 2019 11:05 am The problem is a tight bore , not groove . A 96 Swede with a very tight bore , some are as small as .253 , with tear the jacket on a thin jacketed .264 bullet . Going to a .263 dia bullet or a thicker jacket should cure the problem .
“.253” bore in a 6.5mm barrel? Is that a typo?

Re: 123 Nosler CC in M96 problem

Posted: Mon Feb 25, 2019 10:40 pm
by slowbob2
No , the bore of a barrel is the small measurement . It is the lands . The average military barrel has around 0.010+ deep rifling . So if the grooves are .264 , the lands [ bore hole ] will be -0.010 = .254 . Or if it is tight 0.253