.236 vs .237.....and 4 vs 5R

[65BR]

Looking at another Bartlein for a 6mmBR project, an 8' twist, bullets used up thru 107s.

My last was a 4 groove .237 shot very well.

Thoughts on 237 vs 236,speed and accuracy), and 4 groove vs. 5R -,accuracy and barrel life)?

Thanks for all replies.

 

[Bob3700]

I have had 6mm bbls from three different manufacturers, button and cut. Some were 8 twist, others 7.5. Three have been four groove and one is a 5C, all have been .236 bore diameter.

The button rifled bbl started to give up accuracy at about 2100 rds. Cut bbls have lasted around 2600 rds.

The 5C bbl cleans up real fast and seems to have less copper fouling than the 4 groove bbls.

I can't see any speed difference between the 4 groove and a 5C. My hopes were that the 5C would be a bit faster but that hasn't happened.

Just my observations.

Bob

 

[butchlambert]

Frank Green of Bartlein barrels has posted that a good barrel is a good barrel. Don't get worked up about anything that somebody is hyping up. Ed Shilen has told me the same thing. A 236 barrel may like a different bullet than the 237. I used to be The Barrelman and sold many thousands of barrels. Some shooters wanted big barrels and some wanted small. It didn't matter, some shot better than others and had nothing to do with the configuration. Some people think the 5R and Ratchet barrels clean easier and are easier on bullets. I cannot verify that.
Butch

 

[65BR]

Thanks Bob and Butch, I was wondering if the 236 being tighter would affect velocity. Some say Pac-Nor bbls are tighter,not cal. specific), and perhaps raises speed? I have had some fast Pac-Nor tubes.... If so, due to pressure increase? Or would a 236 bore cause more friction to 'slow' velocity....

OR is it all what the load is for that gun, and as Butch said, some guns are said to prefer various bullets.

Any research done to support any bullet preferences for which bore spec? I seem to recall reading somewhere....and do not recollect if it was fact or opinion.

Thanks all.

It sounds like a roll of the dice as to if I might have chosen the 'best' spec bbl for my needs, or maybe it's more theory, I don't know, must be some subtle differences, perhaps none of which may affect me much in a hunting rifle. Although this build is not for competition, I DO appreciate having ALL the potential accuracy built in by selecting the best components and a great smith.

Thanks all.

 

[nmiller]

My experience is limited with 6mm barrels is limited but I have a Bartlien .237' 8 twist that shoots well for me. I have heard that the .237' bbls are harder to get 105 Lapuas to shoot. The explanation I read was that the Lapua 105s are skinny for their caliber. I have never tried them because they cost much more than the Berger 105 and A-max which both shoot very well in my Dasher. I have HBned some 107 SMKs but I haven't tested them yet. I would bet that 'a good barrel is a good barrel' idea is absolutely right whichever the rifling profile or bore spec.

 

[rcw3]

You can go crazy trying to figure out the .236 vs .237 issue as well as the 4 groove or 5R, etc. rifling issue. These issues have also been discussed and debated extensively on this and other forums. I have tried them all and my advice is pick one and run with it. I think whether you get a barrel that's a 'hummer' is more the luck of the draw sometimes than what choice you make on bore dimension, type and number of lands, etc.

It's funny because as far as I know Pac Nor's 6mm barrels,at least the ones I recently bought) are coming in around .2365 so that solved that problem of the bore size,i.e. it's like the split the difference - done).

Robert Whitley

 

[alf]

I'll take a .236, thank you......

 

[65BR]

Ok, well, had a 237, may try the 236 this time. Maybe over time it will 'wear in' to a 237

Thanks guys.