284 Win reamer

[TRP]

I'm in the process of building a 284 win. This will primarily be a hunting rifle with some occasional non competitive long range fun. I'm using a Defiance Hunter XM length action, 3.20" magazine length, 24" Bartlein #3. I've already received my Peterson brass and Barnes 145gr LRX as that will be the targeted load. The Peterson brass is measuring a very consistent .316 loaded neck diameter and .4985 base diameter. The reamer builder recommended .190 freebore for the 145 LRX. I think I'm going to KISS and leave the SAAMI neck diameter .322. My question is it beneficial in terms of accuracy and brass life to tighten up the base diameter from .501 to .500?

 

[FeMan]

I would leave the base diameter alone. I tried 0.500 on one reamer and get clickers on extraction. I actually went to 0.502 on my latest reamer for Peterson brass. Time will tell if that is too much but IME 0.501 is my minimum.

My reamer neck is 0.3025 and seems to provide enough clearance. 0.322 is more than needed based on my brass but should work. If you are not sure, more-is-better on neck diameter within reason of course.

 

[XTR]

My 7-08 reamer has a .317 neck, and I've seen that number tossed about on more than one 7mm/284 discussion.

 

[rardoin]

As Ironman said...don't go to .500 on the base unless you are fond of ring dies. I have a saum based wildcat and the base of the ADG brass is almost 0.008" under the reamer diameter at the web. It concerned me greatly. I fired 237rds at a match this weekend and two were slight clickers. The precision is excellent.

 

[LC Tikka]

I did .499" base for new 20yr old Win brass. Hunting rifle not built yet, hoping it will work with Forster FL BR die with .310" neck.
LC

 

[KenOath]

My experience with Lapua brass is .501” at the .200”, you won’t get clickers with 10+ firings on brass, .319” is what I run for a no turn .313” loaded round.