6mm bores, .237 or .236 in 7.5 and 8 Twists

[TAJ45]

Hmmf. That will teach you - going to the Dark Dasher Side....

 

[tclaunch]

I`m a devout .236" guy, I do own .237" barrels by Bartlein, Krieger, all in 4 groove. You couldn't run fast enough to catch me to make me run a 5 groove in 6mm. I feel they are fine in other bore sizes, but only tried 1 5 groove in 6mm and it was a disaster. Gold copper fouling, with no help from the maker at all except a suggestion to change the lot number of bullets.

The .237" barrels I have shoot fantastic, but from competitive shooters I know that shoot F-Class, 1200 rounds in and your X-count begins to drop. On the other hand the .236" has been good to 2300, near doubling barrel life.

The .236" barrels in my house are Brux and Krieger, I do have a few .236" 4 groove Bartleins, and they are hammers.

I see the new barrels from Rock Creek with the 4H rifling are .236" bore.

 

[TAJ45]

Interesting info on bbl life diffs. I'm filing that one away.
However, even accounting for your creds, I'd have to say the problem with that one 5 groove had other things going against it, other than groove #. Similar to having a 4 door sedan that was a dog compared to the station wagon. )

 

[ballisticxlr]

I just had 2 8-twist barrels set up in 6XC with polygonally rifled barrels from Columbia River Arms. They don't have traditional lands but when buying the reamer I had spaced that completely and just assumed that it'd be .236" bore. That pilot was a hot dog in a hallway and my smith requested one that fit better and gauged the bore for me. When I ordered the pilot for the reamer there was a little surprise because it was .239". Barrel life with the CRA pipes has always been excellent. Nothing super radical over what a high quality conventionally rifled bore like a brux or bartlein should see but enough to take notice of. I should have my smith gauge the inside of the barrel I just pulled for round count and see what it comes out to.

 

[TAJ45]

I'd be interested in those #s too.

 

[Falfan2017]

Don’t have as much experience as most but I’ve had 8 twist, 7.5 twist 7.75 twist in .236 and in .237 from a few different barrel makers and they all shot pretty much similar with the 105 class bullets. I think there’s more going on here than just the .236 vs .237 debate.

 

[tclaunch]

Barrel life only advantage, accuracy flip a coin.

 

[butchlambert]

So, If any of you have pins in .0001 increments, what do your pins say on the actual bore size. I'll bet the you will find dam# few that are 236 or 237. I believe it is much better for them to be uniform from one end to the other.

 

[Pyscodog]

Ackelyman said my barrel was .236 front to back. As far as barrel life, I'm not a high volume shooter. I have to many guns to shoot anyway. This was going to be a coyote/deer rifle but I still want it to shoot bugholes if possible. I may never get there but I'm going to try. Thanks Guys!!

 

[butchlambert]

Ackelyman said my barrel was .236 front to back. As far as barrel life, I'm not a high volume shooter. I have to many guns to shoot anyway. This was going to be a coyote/deer rifle but I still want it to shoot bugholes if possible. I may never get there but I'm going to try. Thanks Guys!!

You should be fine.

 

[ballisticxlr]

I'd be interested in those #s too.

Welp count me surprised. I called my gunsmith and asked him to gauge my old barrel for me and he came back with results this morning. A .238 pin dropped clean through, a .239 barely started in either end. He's figuring right around .2386" plus or minus a tiny bit. I assume there's some thickness of copper, carbon and/or HBN lining the bore since I cleaned it zero times for the last few hundred rounds. So .239 looks about it. Unfortunately I got that barrel as a drop-in from CRA so I never got the original bore size. One would assume some level of consistency. Also looks like I can chop off both ends and make myself another 6XC barrel.

 

[Infrequent Shooter]

I called Bartlein, I asked if I could send them my barreled action to check out. They said they didn't do that. They recommended having it setback and a new chamber cut. Thats another $300. I didn't like that idea to much. Ackleyman gave me some tips to try, checking max load and velocity was one of them.

Psycodog,,, only a few years late. Did you ever get the 236 barrel to shoot?

 

[Pyscodog]

I built that rifle wanting to shoot the heavier bullets. It hated heavies. Light bullets shot decent but never what I expected from it. It went down the road.