.284 Chamber Question

[swglenn]

I have a new .284 barrel on order and want to get some feedback on chamber dimensions. This will be used in a no neck turn F-Class gun. This barrel will be chambered for 180 gr Berger VLD's in necked up 6.5-.284 Lapua cases. After searching all of the posts here I believe what I need is a 0.317' neck with 0.225-235' freebore using a 0.313' neck bushing. Any suggestions?

 

[taylor]

I just meassured my lap brass necked up with 180 bergers and they measure .312 -313 so you will need a 311 and 310 bushing for a no turn neck 2-3 under loaded round,free bore mine is around .202 for the 180 grn bergers and works great
hope this helps
Grant

 

[rcw3]

If you are necking up Lapua 6.5 x 284 brass you are definitely going ot have a significant donut at the junction of the neck and shoulder where you pulled part of the shoulder of the 6.5 x 284 case up to make it a neck for a 284 Win. A 'no neck turn' set up is not good with this combination. Neck turning,or neck reaming) is the way to go if you are going to do that. The shoulder metal of Lapua 6.5 x 284 brass is a good bit thicker than the neck metal and necking up the brass brings the thicker metal up into the neck area of the 284 case,right at the junction of the neck and shoulder of the case).

Don't rule out using straight up Winchester 284 brass with some weight and other sorting. I found the Winchester, with proper sorting had better case capacity and held pressure better in the web area better than the necked up Lapua 6.5 x 284 brass.

Robert Whitley

 

[TonyR]

I expand the necks on the Lapua Brass to 284 then I turn them. As Robert says, there is a donut in there even after expanding with three different mandrels. I turn my necks using the K&M turner with the carbide pilot which has a cutter on the end that removes the donut pretty completely. You could use this tool just to clean out the donut by removing the cutter.

 

[o2fish]

Anyone else useing .225-.235 Freebore for the 180s ???

 

[Mark Walker in TX]

Glenn, did you get my email?

Mark

 

[JERRYHM]

You need to check out the Whitley 284 reamer. Robert Whitley wrote an article on the 284 in Precision Shooting.

I use the 6.5 Lapua brass necked up to 7MM and neck turned 0.0045' so the neck clearance is about 0.006'. Shooting on the windy Sacramento range this morning my 5 shot group was 1.804' running the Sierra 175 at 2830 fps. Just starting to tune the 284 for the NBRSA 1000 yard nationals this October.

What I have seen with the 284s, neck clearance is one of the biggest problem areas, tight necks is NOT the way to go with the 284. Tight throats are good, tight necks are bad.

I also use Winchester 284 brass, not sure which is better, both shoot very good.

Jerry

 

[o2fish]

What Freebore are most of you useing in the 284 win and 284 Shehane, with the 180 Bullets ???
Thanks
Scott

 

[TonyR]

Scott.
There is a print of the 284 Shehane reamer I am using in the 7mm Guide on this site:

http://www.6mmbr.com/7mm284.html

If I were doing it again, I might have another 0.020 inches of freebore with the 180 Bergers.

I have been shooting with a 0.310 loaded neck in the 0.313 chamber neck. I think I'll skinny up some necks and try more clearance after what Jerry said.

 

[o2fish]

Thanks Tony.
I asked Dave @ PTG to make my reamer for the 180s.And the freebore on my reamer is .186 seems a little sort?? compared to other prints i have seen.
Just wondering what Freebore you all are useing in the 284 win 284 Shehane/
Scott

 

[1000yardstare]

Just got back from the Canadian Fullbore Champs in Ottawa. The Quebec shooters are all talking about building straight .284 F Class rifles over the Winter. They plan to use Winchester brass and sort through the cases. Seems to be this trend for F Classers to drift away from 6.5 to either 6mm or 7mm. I use a 6AI.

 

[taylor]

my 284 shehane chamber is a 313 with a loaded round at 310 and .200 free boar
Grant

 

[swglenn]

Walkertexasranger
Mark
I did not get your e-mail. Glenn