284 Winchester Build - Questions on Chamber - Help

[phil357]

Guys just don't know so any info would be helpful.

I have just had a local gunsmith chamber my barrel. I have about 15 thousand play just above the web of the case when it is in the barrel. What is the correct chamber dimentions and I will probable have the barrel set back and have someone else rechamber it. I just talked to the gunsmith today and he measured the reamer and it measeured .503.

The base at the web is with new brass is .490
The top just before the shoulder is .468
The neck is OD is .308
The neck OD loaded is .310
The neck of the case measures about .013 to .014

Should I just order a new reamer

 

[GLZ]

Ammoguide shows the SAAMI spec to be 0.500 on the case.
heres a link.

http://ammoguide.com/?catid=103

 

[Steve Blair]

I had Pacific Tool & Gauge grind a .284 reamer to match the Winchester brass that I sent them. It has a .313 neck for no to light turning and a .220 throat for 180 Bergers. The lot of Winchester .284 that I have measures .494 pretty consistently. Borden Rifles used this reamer to chamber a 29" Brux for an Eliseo Tube Gun.

It is tough to beat a new, custom reamer that is well employed. The parent site to this forum has a left-column tab titled "Top Gunsmiths" that lists many of the best in the US. I have used several and been very gratified by the results.

 

[TonyR]

The 7mm Cartridge Guide on this site shows a reamer print for the 284 Shehane which is the same as the 284 Winchester at the base of the case body. This print shows a dimension of 0.5029 inches at the case head. I have had 4 barrels chambered with the reamer made from that print and they all shoot great in F-Class competition. I think you will be fine if the chamber dimension is 0.503 inches as your gunsmith says.

http://www.6mmbr.com/7mm284.html#284win

 

[phil357]

Thanks for the info. I forgot to ask what lenght barrels or most people using.

Thanks

 

[Steve Blair]

Tony,
Could that reamer be targeting Lapua brass? My 6.5-284 brass measures .500 at the base.

 

[phil357]

Does anyone know the size of the Lapua Brass?

 

[TonyR]

Definitely Lapua brass. I make my brass by necking up 6.5X284 Lapua brass. A new piece just miced at 0.499 inches. 284 Win bulk brass miced 0.494 inches 6.5X284 Norma brass mics 0.500 inches. I use 31 inch 1:9 barrels. Others use 32 inches. Mine is the Shehane so i can get the velocity with shorter barrels.

 

[6BRLongRange]

I'm from your area also Phil. Who are you using for smithing work?

 

[phil357]

I had Coal Creek do it... I didn't know anyone else local.

 

[Preacher]

I doubt you'll ever see new Winchester brass these days that will measure .500.......

 

[o2fish]

Hmm my reamer print shows .5019, do you guys see any problems with that ? im about to chamber a new barrel.
Scott

 

[TonyR]

I just looked up the chamber dimensions for the SAAMI and CIP standard 284 Winchester chamber in QuickDesign. The diameter at the bottom of the case body is 0.5024 inches under both standards. The CIP standard for the 6.5X284 Norma is 0.502 inches. I don't know if these are minimums or maximums. Maybe a good question to ask Dave Kiff at Pacific Tool before chambering a barrel.

 

[phil357]

up

 

[Steve Blair]

I received my barreled action from Borden with both barrels, the 29" Brux .284 mentioned above and a 31" Bartlein .308. PT&G sent me the .284 chamber print and it shows .500 at the chamber mouth, .200 forward of the bolt face. They only sent me a hard copy, so I scanned and attached the image. This should be just about right for my Winchester brass. It would still fit Lapua 6.5-284, might have to touch the body with a full length sizing die.