Berger 108gr BT Help

[Jud96]

I’m planning to build a 6mm Varmint rifle for 103-108gr bullets and I have some questions. I was planning to run the Berger 108gr BT bullets initially with a 0.119 FB .243 and a 1-8 twist barrel. However, I’m getting some conflicting information. According to Berger’s information the 108 has a relatively short bearing surface (0.344) and my math shows it would pair really well with the 0.119 freebore. On the other hand I’ve seen comments made on this forum and other trusted sources say that the 108 BT has a long bearing surface compared to other Berger’s in its weight class. I’m trying to determine if I should look at other options or plan to add some freebore to the chamber with a throating reamer. My options are limited in today’s market so I’m trying to work with what I can find. My other choice is the 103 VTAC bullets from Vapor Trail, I don’t know anything about them other than they have a great reputation. Any bullet suggestions or help with the 108 BT’s bearing surface length and ideal freebore for it in the .243 Winchester is much appreciated. Thank you!

 

[Jud96]

Anyone?

 

[JFrank]

For my BRA I use a .120 free bore for the Berger 108 targets seated at .026 jump
I use a .100-104 for the vapor trails seated for a .025 jam

 

[X-Caveman]

.119 will work with either of those fine bullets. I wouldn’t go longer on the freebore, as it grows a little with every shot. I would, however, recommend making sure the freebore diameter is 1/2 thou or so larger than groove dimension.

 

[HTSmith]

I have a .105 fb 6br reamer and the 108’s work great.

 

[Jud96]

For my BRA I use a .120 free bore for the Berger 108 targets seated at .026 jump
I use a .100-104 for the vapor trails seated for a .025 jam

Thank you! Where does that freebore put the 108 in the case neck?

 

[Jud96]

I was just concerned with the .243 Win having such a short neck, compared to the BR and BRA, that I would need more than 0.119 freebore to keep the bearing surface inside the case neck.

 

[JFrank]

Thank you! Where does that freebore put the 108 in the case neck?

Sorry my comprehension was poor this morning, I focused on 6 mm and completely over looked the 243 win you’re asking about.

 

[X-Caveman]

Sorry my comprehension was poor this morning, I focused on 6 mm and completely over looked the 243 win you’re asking about.

Oh, darn. Me too! I have zero experience with .243 Win. Sorry.

 

[coj0502]

I give a couple of dummy rounds to my smith and he sets the freebore based on them, it just seems easier that way.

 

[Jud96]

I give a couple of dummy rounds to my smith and he sets the freebore based on them, it just seems easier that way.

Yeah I’m thinking about just making some dummy rounds and throating the chamber to fit them. I was seeing if I could be lazy and just run the 0.119 FB and call it good haha. I appreciate the help though guys!