.274 CHAMBER NECK & STARLINE BRASS

[Bill Norris]

Just a heads up. If you have a .274 neck chamber and plan to shoot the 115 gr. DTACs you may want to carefully check a loaded neck diameter. Don't know if anybody has seen this yet but wanted to mention it. A friend brought over his Starline brass for his new 243AI that he will soon be receiving from Zack. (ODCR) The reamer is normally a no-turn. I started going thru the brass to prep it and found the neck thickness to be @ .015 and a loaded neck diameter with the 115 gr. DTACs measures .273 to .2735 with my micrometer. Since the chamber neck diameter is .274 it will need to be turned down to .014 neck thickness in order to be at .271 loaded neck diameter which is where my Lapua brass normally sits and gives adequate bullet release with the carbon sine-wave pattern touted by some B R shooters to be correct.

 

[Bob3700]

Bill,
Is the 115 DTAC larger in diameter than say a 107 SMK. I do believe the 105 Bergers are a bit smaller than either the DTACs or the 107s.

 

[Bill Norris]

Bill,
Is the 115 DTAC larger in diameter than say a 107 SMK. I do believe the 105 Bergers are a bit smaller than either the DTACs or the 107s.

The lot that we have measures the same as the 107 gr. Sierra M K. I'm thinking the difference is in the brass necks.

 

[SmokinJoe]

I have also found Starline necks to be a bit thicker. Thanks Bill, for bringing that out for those that don't know, word to the wise.