.236 vs .237 Bore diameter for 6mm

[xp100Rem700]

Does any one have any experience with the .237 bore diameter in the 6mm. I was told that accuracy was better with .237. Anyone have both for a solid conclusion instead of opinion or hear say? Thanks
Ray

 

[skeetlee]

ray
this is a good question and all i know is brux 6mm 8 twist barrels sure do there fair share of winning and they are .236 bore barrels. anyone else have an opinion base fact or comment? Le

 

[dreever]

A couple of years ago I took a survey among a dozen top gunsmith/shooters at the time and ask them that exact question. It was about evenly split. An interesting note however is that the short to mid range guys chose the .237 bore and the 1000 yard guys opted for the .236.
Myself I've always bought .237's and have been happy. Undersized bullets like those from Lapua seem to work better in the .236 bores. I like Bergers leaning toward the fat side (.24310-.24330) for my .237. Seem to shoot real good for me.

Danny

 

[VooDooMagic]

I agree that the Lapua Scenars and JLK bullets shoot best in my .236 Kreiger 8 twist...

 

[alf]

This question comes up almost weekly.......

General rule of thumb is to shoot close range BR with the .237, cause most BR bullets are flat base with a pressure ring that runs the diameter up to around .2435 or even more.

Long range, for 600 or 1000, use the .236 cause most all shoot boatail bullets that have no pressure ring to speak of, so they run on the smaller diameter size, around .2430, give or take.

I had a good shooting barrel that measured .2367, and shot great with some of the first 105 VLD's that were fat, and measured .2435. All was good......til I ran out. I had several other lots of 105's, up to .2433 in diameter, but none shot as well as the originals. That barrel is now on a prairie dog gun, and all my Kriegers are .236.

Some claim there's no difference, but I'll gladly let them have the .237's.......

 

[Phil]

The response i received from Krieger parallels what Alf has said...

The .237 bore is better for the lighter bullets.

The .236 is used for the longer/heavier/streamlined bullets.

 

[dreever]

If you buy any 6mm barrels from Bruno's they'll be .237. That's all Bruno's ever orders.

 

[tenring]

Does the same theory hold true for other calibers? Can various bore diameters be ordered in say 22 or 30 caliber?

 

[fullersson]

Krieger offers tight bore barrels in 22 and 30 cal.

 

[rcw3]

Sometimes I wonder if it's more a "flip a coin" decision than anything. Right now I have some Bartlein 6mm 1:8" twist Heavy Varmint barrels I am selling and I have them in both .236" and .237" bore size and some customers buy the .236" and some buy the .237" (i.e. for the same expressed reasons) and all seem to be happy with them. I have shot both and I am not sure it really matters. Alf's analysis is probably as good as it gets. I don't know there's ever going to be anything conclusive on this. Make a choice and work with it. Good luck!
Robert

 

[cmillard]

i have a .236 krieger 5R 8 twist that shoots 105 berger vlds extremely well. also shot 107 sierras in the .2s.

 

[alf]

If you buy any 6mm barrels from Bruno's they'll be .237. That's all Bruno's ever orders.

I've had a couple of spirited conversations with Lester about this, and came to an impasse.

He's lost more than one sale because of it.......

 

[alf]

This question comes up almost weekly.......

Not only does it come up that frequently...............

We've got two threads going on about it right now........... ;D

 

[flatlander]

My first two Dasher bbls. were both .236" 1:8 Kriegers that have shot extremely well with Lapua 105s. However, I also had another .236" 1:8 Krieger that showed no preference for Lapuas over any of the other 105-108gr bullets I shot in it. I've also got a .237" 1:8 Bartlein 6x47 that's proven time & again to be one of the most accurate bbls. I've ever owned with DTAC 115s at 1000yds. There are also two .236" 1:7.5 Kriegers in the safe in 6x47 that are very good. One of them is on a LR BR rig that I use to shoot BR Varmint Silhouette, and it's excellent with a variety of bullets. IOW, I kinda doubt that either bore size has a clear advantage over the other.

 

[johara1]

Has any body ever checked to see if the bore dia. is what is written on the barrel? I had one 6mm that had been marked .250,so you may be taking a lot for granted. I have a Bartletn .237 ,a Kreiger .237 and a Brux .236 and they shoot the DTAC. 115 very small.........jim

 

[bozo699]

My first two Dasher bbls. were both .236" 1:8 Kriegers that have shot extremely well with Lapua 105s. However, I also had another .236" 1:8 Krieger that showed no preference for Lapuas over any of the other 105-108gr bullets I shot in it. I've also got a .237" 1:8 Bartlein 6x47 that's proven time & again to be one of the most accurate bbls. I've ever owned with DTAC 115s at 1000yds. There are also two .236" 1:7.5 Kriegers in the safe in 6x47 that are very good. One of them is on a LR BR rig that I use to shoot BR Varmint Silhouette, and it's excellent with a variety of bullets. IOW, I kinda doubt that either bore size has a clear advantage over the other.

IOW ?

 

[6BRinNZ]

Hi,

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

Wayne - IOW...In Other Words

Thanks

 

[alf]

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

.236 or .237 is the bore dimension.

.243 is groove dimension.

 

[rcw3]

. . . I had one 6mm that had been marked .250. . . . .........jim

Just a minor manufacturing tolerance issue - should shoot fine - a wee little slop around the bullet - no big deal . . .

On a serious side - you are right - we take the barrel markings for granted and mistakes do happen.

Robert

 

[bozo699]

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.