Which 6.5-284 reamer

[FrozenTundra]

Can anyone please explain the difference between these two reamers or why I would want one over the other?

6.5-284 Match 0.2970 1*30 0.187 HSS GO
6.5-284 NORMA Match SAAMI 1*30 SAAMI HSS GO

 

[BrentM]

I believe the top one is tight chambering and likely requires Turned neck. The SAAMI spec is a No Turn neck with more head space. For example Lapau brass is 1.832 and fire formed in my chamber it needs to be 1.838 to chamber a round. At 1.840 it is tight and the bolt requires pressure to close. My redding body die bumps my case back to 1.838 and I am back in business.