.284 Chamber Questions

[Jud96]

Hello all. I'm thinking of building a .284 in the future for a general purpose hunting rifle that's light and effective out to 700 yards on medium game. I have done a lot of research, but I can't seem to find exactly what I'm looking for. I want to be able to use Winchester or Bertram brass, both measure around 0.495 at the base. All of the reamer prints I can find have a 0.500-0.501 base. I understand this works with Lapua, but this seems oversized for the Winchester spec brass.

Is there any reamers I can purchase that are spec'd for Winchester brass, or will I have to custom order one with a tighter base diameter and the neck and freebore specs of my choosing? Thanks!

 

[can1010]

you will have to custom order. the saami spec is .501.
decide on which dies your going to use and then decide on reamer. the Hornady and rcbs that I used will size back down to .4965 and if chamber is .501 you overwork your brass and it will crack at case web. I switched to whidden sizer after having Bertram brass crack after 5 firings and have not had any more problems. my chamber was cut with 284 match reamer and it is .501.
stay with Lapua or Bartram brass the new Winchester is junk I would use Hornady before win brass

 

[Jud96]

Sounds good. I have used Bertram brass before and it has been excellent. I don't want to deal with donuts and neck turning with the Lapua brass, and I also don't want junk brass so I'll stick with the Bertram or Norma, if it ever comes back out.

Do you know exactly what your Bertram virgin brass measured at the head? And what dimension does the Whidden dies size your brass to? Thanks

 

[MagnumManiac]

This is a quandary many face, but in reallity there is no problem at all.
If you have a good set of micrometers, particularly a set that reads 1/10,000".
I would measure your brass cases, in nearly EVERY brand of case, you will find they are .005" UNDERSIZED from whatever specs you look at, whether it's SAAMI or CIP.
Even my Lapua 6.5x47 brass is .005" undersized in the base just above the extractor groove, this is normal in my experience as this part of the case is actually OUTSIDE the chamber when the bolt is closed.
It's the measurement .200" up from the case head/boltface you need to be concerned with.

Cheers.

 

[elkaholic]

This is a quandary many face, but in reallity there is no problem at all.
If you have a good set of micrometers, particularly a set that reads 1/10,000".
I would measure your brass cases, in nearly EVERY brand of case, you will find they are .005" UNDERSIZED from whatever specs you look at, whether it's SAAMI or CIP.
Even my Lapua 6.5x47 brass is .005" undersized in the base just above the extractor groove, this is normal in my experience as this part of the case is actually OUTSIDE the chamber when the bolt is closed.
It's the measurement .200" up from the case head/boltface you need to be concerned with.

Cheers.

+1

 

[Jud96]

Thanks for the replies guys! I really never paid attention to reamer dimensions vs. what the brass actually measures until now. I never thought of it until researching the .284 and the Lapua vs. SAAMI spec brass. I've found some .284 reamers available with longer throats and the SAAMI specs, so I'll probably just run with that instead of ordering a custom reamer.

 

[AZShooter]

Jud96,

I read an article in Precision Shooting (IIRC) years ago where a guy built a 6mm-284 with necked down Winchester brass. The title was "Make Mine a 6mm-284" He had some issues with the primer pockets loosening after a few firings. He had his reamer base reground smaller. How much? I don't remember but he said it kept the base from expanding as much and allowing the brass to have a longer primer pocket life. I would think you could talk that through with the reamer maker and come up with a dimension that is more to your liking and also allow for easy extraction.

I had a custom 284 reamer made to my specs. Throated to allow lands contact with the 168 VLD, seating limitations of 3.050" magazine and a .315 neck. I have hundreds of old 284 win brass and wanted to turn the irregular neck wall thicknesses.

Not sure if you know that the owner of Grizzly Industrial had Norma make him some 284 win brass. It is supposed to be the best ever made. It was offered through the now defunct bullets.com. This brass is still available through Bruno's:
http://www.brunoshooters.com/product/80953.html

As to the quality of this brass:

Bullets.com's contract with Norma calls for advanced production methods to make sure the new brass is truly "match-grade" and long-lasting. To ensure that primer pockets stay tight for many firings, the caseheads on the new brass will be double-stamped for improved hardness and strength. Additionally the new brass will go through an additional draw stage to ensure ultra-uniform casewall thickness.

link: http://bulletin.accurateshooter.com...6mm-dasher-and-284-win-brass-for-bullets-com/

 

[TOM H]

Thanks for the replies guys! I really never paid attention to reamer dimensions vs. what the brass actually measures until now. I never thought of it until researching the .284 and the Lapua vs. SAAMI spec brass. I've found some .284 reamers available with longer throats and the SAAMI specs, so I'll probably just run with that instead of ordering a custom reamer.

That Betram brass has already been shot.

https://www.ozfclass.com/phpbb/viewtopic.php?t=8138

Reading that looks like used Lapua reamer would work for Betram brass, same for Norma 284

http://forum.accurateshooter.com/threads/norma-284-winchester-brass.3891088/

Myself I wouldn't base anything on Win brass when you have Norma/Betram brass

 

[DLJ6]

15 years ago when having a custom 25-284 Encore barrel chambered, I didnt realize the dimension variation existed. Learned the hard way that the Lapua brass would not chamber. No worries though as my loads using Winchester brass work extremely well and case life good. I would love to have a Tikka bolt gun in 284Win its an efficient case.

 

[Montana Guy]

Hello all. I'm thinking of building a .284 in the future for a general purpose hunting rifle that's light and effective out to 700 yards on medium game. I have done a lot of research, but I can't seem to find exactly what I'm looking for. I want to be able to use Winchester or Bertram brass, both measure around 0.495 at the base. All of the reamer prints I can find have a 0.500-0.501 base. I understand this works with Lapua, but this seems oversized for the Winchester spec brass.

Is there any reamers I can purchase that are spec'd for Winchester brass, or will I have to custom order one with a tighter base diameter and the neck and freebore specs of my choosing? Thanks!

I would suggest a 284 Shehane. Just the 284 with straighter walls. The shoulder angle stays the same. Real easy just load 284 then fire form. Great results. Can get to 2900 FPS. Last weekend, Third time out and fire forming cases, shot at 600 yds on the NRA MC 1FC shot 193 3X. Muzzle velocity at 600 was 2187 ave. Easy to build easy to reload for so just a suggestion if you are interested in 284.

 

[JohnMill]

This is a quandary many face, but in reallity there is no problem at all.
If you have a good set of micrometers, particularly a set that reads 1/10,000".
I would measure your brass cases, in nearly EVERY brand of case, you will find they are .005" UNDERSIZED from whatever specs you look at, whether it's SAAMI or CIP.
Even my Lapua 6.5x47 brass is .005" undersized in the base just above the extractor groove, this is normal in my experience as this part of the case is actually OUTSIDE the chamber when the bolt is closed.
It's the measurement .200" up from the case head/boltface you need to be concerned with.

Cheers.

Great info and practice with them mics. to measure a tenth is not a natural thing but not too difficult

 

[Jud96]

I think I've decided to go with Norma brass and the .284 Norma Match reamer from Grizzly. My next question is, does anyone know of any other dies besides Whidden that do not over work the case head by sizing it too far down? I originally was just going to run Hornady dies, but from what TOM H reported, I don't want to be having case heads separaing after 5 firings.

 

[MagnumManiac]

Case head separation is ONLY caused by pushing the shoulder back excessively, on the order of .005" or more.

You do realise you cannot size the solid head portion of the case, right?
As long as the shoulder is pushed back .002" and the body is reduced on the expansion ring .002", you should have perfect chambering and no chance of a head separation.

Hope this helps.

Cheers.

 

[JohnMill]

Case head separation is ONLY caused by pushing the shoulder back excessively, on the order of .005" or more.

You do realise you cannot size the solid head portion of the case, right?
As long as the shoulder is pushed back .002" and the body is reduced on the expansion ring .002", you should have perfect chambering and no chance of a head separation.

Hope this helps.

Cheers.

Keep pouring it on, Mag. You got a lot of ground to cover (to bring 'em to your level.