6.5x284 help?

[steeltraps]

I thinking about rebarreling my 284 shehane to strait 6.5x284. Can some one please give me a neck ID? Does anyone know what the neck measurement for a 6.5x284 Lapua loaded with a 140 berger will be? Loaded neck with Lapua brass?

 

[Len Backus]

0.2935

 

[steeltraps]

Thanks. I have a barrel. I have bullets , stock, action, every thing but the reamer. I am thinking .297 reamer with zero freebore. I found a 6.5x284 modified case today so I can have my gunsmith set -up the bullet exactly perfect.

 

[AZShooter]

Are you going to neck turn the brass or go for a no turn neck?


In the article below they mention that loaded lapua brass has an neck OD of .296". Your choice of a .297" chamber neck would be too tight especially with unturned brass. All it would take is one random piece of brass to be a bit thicker to create high resistance to bullet release with subsequent high pressures.

If you were going to turn the lapua brass you would be fine.


Accurate Shooter has an excellent article on the 6.5-284.

6.5-284 Cartridge Guide within AccurateShooter.com

Here is part of the article which pertains to the neck dimension:

Preferred Neck Diameter

Preparing for this article, we measured some current un-turned Lapua brass with a 142 SMK in place. The outside neck diameter at the mouth was 0.296″. Most top shooters do turn their necks for consistency, but there is no prevailing standard for neck-wall thickness. Check with a dozen 6.5-284 benchrest shooters, and you'll find a wide variety of chamber neck diameters, from 0.286″ to 0.298″. There does not seem to be a magic number. Bill Shehane runs a .290″-neck chamber with an 0.288″ loaded neck (.002″ clearance). The Hoover family has won numerous matches shooting 0.296″-necked rifles with an 0.293″ loaded round (.003″ clearance). John Hoover told us "after shooting this cartridge for many years, I strongly believe you need .003″ clearance on the loaded round, minimum, and .004″ won't hurt you. I've seen a lot of people have problems with too little clearance."

 

[steeltraps]

This is an old article. Old brass. Len says 293.5 and several others say 294. So it you say 293-295, with 295 being the largest 297 will work just fine. I shoot f-class and have experience with turning 1000ths of necks. I dont like it but can do it! The reason I ask people on here was, for resent size of 6.5x284 brass, not the old gold box stuff, the NEW blue box. I will only except , as I no more than 4 ths total clearence. So 2 ths is fine or 3 ths,