.236 vs .237 Bore diameter for 6mm

[Steve Blair]

Hi,

what is .236 & .237 a measurement of? i.e. isn't a 6mm a .243 bore?

Wayne - IOW...In Other Words

Thanks

Thanks, I have never been good at abbreviations, and + 1 what ALF said
Yup, .243 bore, and .236 or .237 groove dimension.
Wayne.

No, .236 or .237 is the bore diameter, .243 is the groove diameter. How could the bore (the initial hole) be larger than the groove?

 

[alf]

Whoops, I knew that. Duh moment, I'll edit.

 

[bozo699]

Whoops, I knew that. Duh moment, I'll edit.

And I followed suit,....OOOOPS!
Wayne.

 

[6BRinNZ]

Thanks guys, so is the difference between .237 and .243 the land depth? I know I am getting this off track but I am just trying to udnerstand the dimensions and the significance of them. Maybe I should just google

 

[Steve Blair]

Thanks guys, so is the difference between .237 and .243 the land depth? I know I am getting this off track but I am just trying to udnerstand the dimensions and the significance of them. Maybe I should just google

Yes. If the bore is .237 and the groove diameter .243, individual groove depth (or land height) is .003.

 

[HPMike800]

My 6BR's for 105-107gr shooting have been .237's and they have been good 600yd guns.

I went with a 5R .237 for my 6SLR to be a little easier on the bullet. An attempet to keep them from going "Poof" we'll see.

 

[fullersson]

Sleepygator, I'm not trying to correct you I just want to make sure I haven't completely missed the boat somewhere. A .237 bore with a .243 groove gives you .006 groove depth (land height) doesn't it? Like I said I'm not trying to correct anyone just wanting to make sure I understand this stuff. If I'm wrong please explain how the answer is .003. Thanks, Brian.

 

[CaptainMal]

Oh man --- Why did I read this?

Probably because I just got my new Krieger replacement bbl for my 6mm Dasher and it's a .236"

If the top of the lands are .237" across and the grooves are .243" across (bore diameter), would not the depth of the land be .006"?

Sometimes the simplest thing is the most difficult for my feeble brain.

 

[NateG]

There's a difference in *diameter* of .006 between bore (land) and groove, but only half of it's on each side, which gives .003" height of the land. (Or, depth of the groove, if you want to think of it that way.)

And, having an odd number of grooves doesn't change the numbers, either.

 

[Steve Blair]

Nate is correct. The land height is the groove radius minus the bore radius or the groove diameter minus the bore diameter divided by two. Maybe the attached image will make it more clear.

 

[fullersson]

Man I'm slow. Thanks for clearing that up. Brian

 

[CaptainMal]

Picture is worth a thousand words.

I knew that. Thanks.