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Cut Rifling - One Groove Deeper

lazyMlazyK

Silver $$ Contributor
Question for the group - in a cut-rifle barrel, if one of the grooves in the bore had one extra pass made on it, making that groove a little bit deeper than the others, how could that affect how the rifle shoots?
 
If I remember correctly, single point cutters remove about .0001 per pass. Given that, I do not think that it would make any difference. I think that the quality of the finish lapping would more likely to be a factor.
 
Thanks for your input. For the sake of the discussion, what if there were 10 extra passes made on one groove?
 
If a groove is a thou deeper... the bullet might not contact it at all? If it did, your exiting bullet would be lopsided.
 
Question for the group - in a cut-rifle barrel, if one of the grooves in the bore had one extra pass made on it, making that groove a little bit deeper than the others, how could that affect how the rifle shoots?
I had a 5r with one groove .0005 deeper. 4 dialed in to zero with one .0005 off. The bore dialed in well. I went ahead and chambered it since it was aleady in the lathe. 4 grooves looked great and one was not even touched. Lapping mark right to the end of the neck. The manufacturer replaced it. I gave that barrel to a buddy. I told him about the one groove being deep. But its free. He cut the tenon off and rechambered the barrel in 308. That rifle shoots extremely well for a sporter. How much worse was it than if it was right? Dont know, because youd have to test that on a known BR platform. And if i ever see that in a br barrel I doubt anyone would waste good bullets to even want it for free. I do have a BRA barrel here thats so big no groove was cut by the freebore. I doubt that one will shoot. As I got close to .244 on my groove diameter testing I did see accuracy start to fall off maybe .1 to .2 moa
 
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I had a 5r with one groove .0005 deeper. 4 dialed in to zero with one .0005 off. The bore dialed in well. I went ahead and chambered it since it was aleady in the lathe. 4 grooves looked great and one was not even touched. Lapping mark right to the end of the neck. The manufacturer replaced it. I gave that barrel to a buddy. I told him about the one groove being deep. But its free. He cut the tenon off and rechambered the barrel in 308. That rifle shoots extremely well for a sporter. How much worse was it than if it was right? Dont know, because youd have to test that on a known BR platform. And if i ever see that in a br barrel I doubt anyone would waste good bullets to even want it for free. I do have a BRA barrel here thats so big no groove was cut by the freebore. I doubt that one will shoot. As I got close to .244 on my groove diameter testing I did see accuracy start to fall off maybe .1 to .2 moa

But how would it shoot if it had a barrel nut? I kid I kid. Don't hate me.
 

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