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My father, a fine shot, called groups like yours (and a lot of mine) "knowing when the gun was going bang".

It was his theory that the actual firing of the gun should be a surprise, as you squeezed while on target and held while wavering off. Anticipating let off causes twitches in the trigger finger that translate to lateral twitches in the barrel.

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Well, I didn't have any proof to show that this friendly challenge to my manhood was unfounded , so I let it slide until I could show that my shooting skills are still good enough to remind me that the time I spent shooting rifles as a kid were not something I would likely forget - and that I'm a better shooter than this rifle.

So, suspecting that throat erosion might be the reason I was getting those annoying and unpredictable groups that led to Eddy pointing at my shooting skills - and continuing the sickness of "making it better" - I ordered some of David Tubbs' "Final Finish" abrasive-imbedded rounds to see if a fire-lapped, smoothed bore and throat would result in a better group. After firing the 20 rounds of abrasive stuff, I fired 2 shots to move the ~ 2" vertical point-of-impact change a little closer to the target center - but without trying to get it dead-on and then fired this 5-shot string fairly quickly:



Eddy, you'll have to sit for a long time at the range to see a better group than 4 of those 5 from a .30cal sporter rifle at 100yds.

The problem is the outlier. That was the 3rd shot in the string and the rifle jumped up on the bags on that shot. I changed to cheaper ammo and the same thing happened on 1 round out of 5, but with a larger overall group. I "think" I know now that the rounds with more recoil are the result of a pressure spike - maybe caused by throat erosion, which is allowing some rounds to cock as they jump to the lands. Maybe, maybe not, but I decided to trust my gut feelings and once again try to "make it better".

The barrel is now being rebored to .35 Whelen, 3-groove, 1:14" twist rate. It might shoot better when I get it back - or it might shoot worse..... dunno, because I've never had a barrel rebored. I did have the itch for a Whelenator anyway, though.

Frank

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'89 G-Raider Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 155k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, 165A alt., Lifeline AGM, Rust-Oleum

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