why a change in group size?

J

Jkob

Guest
I had done a new barrel, trued action, bolt, bedding on a clients gun. He came back with this: He said when he first shot the rifle, 200 rounds or so, the accuracy was great and group size occasionally smaller that 3/8" which is all he wanted in a prairie dog rig. It was a CM barrel and after he had shot it, he rust blued the barreled action. Beautiful job by the way. Anyway after this blueing, he took it out and shot it again and now can't get anything better than 1 1/2" groups. I did a recrown and re-lapped the lugs and sent him on his way. have not heard back yet.

I can imagine a bunch of stuff could have caused the increase in group size, but what is your opinion on this.

Oh, PS. It was a 204 ruger and the bore was scoped and appeared clean and sharp.

Jim
 
I am no gunsmith but just using a little common sense I'd guess the rust blue has done nothing. My guess would be the sudden accuracy loss is the result of some problem with the bedding or some aspect of the way the rifle has been reassembled. Maybe he was has got the magazine box bound up somehow or has something else making contact where it shouldn't ??

Perhaps there was some change in the components of his load, a change in powder lot number or a new batch of factory ammo or something like that.

Seems obvious to point the finger at the bluing job but unless the crown was damaged (which you fixed) there doesn't seem much else a blue job could hurt.
 
I've seen some rust blued barrels on which the bore was etched during the process. Accuracy was adversely affected. Regards, Bill.
 
IMO-- Suggest to look at "receiver bolt" torch's, bedding and lug issues, scope and mounts, or anything else that could have been affected when the rifle was taken apart for bluing.


Happy Shooting
Donovan Moran
 
Are talking real rust bluing here? Pickle the grease out, cover with the goop, stick into a steam cabinet until it rusts, then break off the growth with a wire brush, repeat until the color is right, neutralise & oil up?

Can't see any chance of that being an issue to accuracy! :eek:
 
Maybe the scope went south? I've seen that happen on several occasions. It can happen suddenly and for no apparent reason. Have him try a different scope.
Just a shot in the dark...........

-Mike-
 
Slow rust bluing is an entirely different process from hot caustic bluing. As opposed to hot caustic bluing with the multiple tanks for degreasing, cold water rinse, 300 degree bluing salts, boiling water and water displacing oil bath where the bore is usually blued, the slow rust bluing should have the bore sealed off to prevent the corrosive solution from damaging the bore. I would have a borescope down that barrel as soon as you can to see if it has been properly protected during the bluing process.
 
Thanks for all the input. I did not think the blueing had anything to do with the accuracy. The guy just got called and said it was back to shooting great again. I guess it must have been the crown. I think when he wire brushed the crown while blueing, he must have scratched it up a bit. I can't help but think maybe the lapping of the lugs may have helped also.

Thanks again

Jim
 
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