Straight 284 Reamer Questions ???

[lawrence97]

I am in the process of building a straight 284 Winchester for F-class and I am stuck with the dilemma of what reamer specs to use for my chambering.
My gunsmith has a reamer with a .313 Neck and .207 freebore.

I also spoke to PT&G and they have a reamer with .313 neck and they recommended a freebore in a range of .188-.200

I will be using Lapua 6.5x284 brass and neck it up with a K&M 7mm mandrel. I will be pushing Berger 180 Hybrids

What are most of you using for reamer specs?

With a .313 chamber, how much are you turning your necks? And what neck bushings are you using?

Thanks for your comments.

 

[turbo54]

Loaded Lapua brass will measure ~.311-.312

I can't think of any reason to choose less than .200" free bore, but .188-.220 will do just fine.

Dave likes the .188 figure because an F open championship was won with it.

Just be sure you use a reamer intended for Lapua brass, if that is the brass you're intending on using. WW Super brass is a little smaller down at the 200 line.

 

[KT]

The reamer your smith has will work well. You will need to turn the necks on the Lapua brass to atleast .309, so you will take off about .002 to .003 from the neck. I would get a 307-309 bushing and then figure out which bushing allows for the best accuracy.

Check to see if your smith has a floating reamer. When running the 180 hybrids you need to seat the bullet out pretty far to avoid any donut problems. You will more than likely have a freebore longer than .207 if set up to proper length for the Hybrid.

My spec
315 neck
220 freebore.
Overall length of loaded round using hornady comparator: 3.560

Hope this helps.

KT