Cut Rifling - One Groove Deeper

[lazyMlazyK]

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?

 

[BoydAllen]

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.

 

[lazyMlazyK]

Thanks for your input. For the sake of the discussion, what if there were 10 extra passes made on one groove?

 

[LVLAaron]

If a groove is a thou deeper... the bullet might not contact it at all? If it did, your exiting bullet would be lopsided.

 

[Alex Wheeler]

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

 

[LVLAaron]

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.

 

[Alex Wheeler]

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

Thats classified information.

 

[B Nettesheim]

One would think that it would put the bullet of balance

 

[DShortt]

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

Savage!

AGT reference there if'n you don't know.

And you are an instigator of the highest order.