Thread: . 284 Winchester

Originally Posted by Puffin

Further to my earlier post, I've since cross-checked several dimensions on the Manson and JGS regular SAAMI reamer drawings.
The neck diameter runs from 0.323" to 322". Necked up but unturned 6.5-.284 Lapua brass measured 0.3120 - 0.3126" loaded, so that is already 10 thou expansion on firing. If the brass is then turned and tidied up for a donut then 0.310 is about right. That is quite a lot of to-and-fro for each firing/resizing cycle. Online reports indicate that the Norma .284Win brass has thicker neck walls than either the Winchester or necked-up Lapua brass at 0.316" give or take. This might be reason enough to use Norma brass in a standard chamber, but also a potential safety issue if the chamber is cut with a non-standard neck.

The SAAMI profile does NOT include parallel sided freebore. It tapers down from 0.290" ahead of the neck at 47' 33" (0.7925°) in one continuous freebore/leade. At that angle is narrows to the nominal bullet diameter 0.284" at 0.217" ahead of the commencement of this profile, so this figure can be substituted roughly for freebore. It looks like many here are getting good accuracy from their .284s, but based on this I don't imagine many of those bullets that aren't 180gr are out near the lands.

Yes that all sounds about right.

My M595 was rechambered a long time ago before my ownership.

It has a .322 neck, I'm running new WW brass in that which measures .313 on a loaded round. So yeah it will be working the necks alot, very important to annual.

When I first got the rifle it came with some fired WW brass I noticed some of the necks were split or split after I fired them once or twice.

When I got my t3 rechambered I got gunworks to use their other reamer with a .317 neck and a different lead angle.

In this rifle I have used necked up 6.5-284 Lapua brass which I neck turn to remove the donut that forms after expanding. A loaded round of this measures .311

I always remember reading that the 284 win doesn't like too tighter neck clearances.

In loading for both rifles I've always found that I cannot run the powder charges that I believe I should be able to in the barrel with the .317 neck.

I don't know if it's due to the lower neck clearance or the different lead angle.

Whereas the old M595 with the big sloppy neck has always been able to run the charges that Quickload tells me I can without seeing pressure signs too soon on a ladder.

Originally Posted by GWH

...doesn't like too tighter neck clearances.

From my online searching on this 284win-specific topic (embarrassingly extensive) the anecdotal reports were for an effect on accuracy rather than early pressure signs. < 0.003" ( 1.5 thou each side) gave flyers that were absent for larger clearances.
.004"-0.006" was thought to be a good middle ground between avoiding this effect and working the brass unnecessarily hard.
So, yes, at 0.006" I think it might be something else. What were the signs in the Lapua brass in the T3 please that led you to call a halt to the load development ? Ladder? I'm not sure I follow that. What about the cases dimensionally and extraction?

Originally Posted by Puffin

From my online searching on this 284win-specific topic (embarrassingly extensive) the anecdotal reports were for an effect on accuracy rather than early pressure signs. < 0.003" ( 1.5 thou each side) gave flyers that were absent for larger clearances.
.004"-0.006" was thought to be a good middle ground between avoiding this effect and working the brass unnecessarily hard.
So, yes, at 0.006" I think it might be something else. What were the signs in the Lapua brass in the T3 please that led you to call a halt to the load development ? Ladder? I'm not sure I follow that. What about the cases dimensionally and extraction?

Heavy bolt lift and ejector marks on brass at charge levels lower than I expected the max would be.

After I neck turned a bit more things improved and I could run higher charge weights. But I still can't run it where I thought I'd be able to.

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Originally Posted by GWH

Yes that all sounds about right.

My M595 was rechambered a long time ago before my ownership.

It has a .322 neck, I'm running new WW brass in that which measures .313 on a loaded round. So yeah it will be working the necks alot, very important to annual.

When I first got the rifle it came with some fired WW brass I noticed some of the necks were split or split after I fired them once or twice.

When I got my t3 rechambered I got gunworks to use their other reamer with a .317 neck and a different lead angle.

In this rifle I have used necked up 6.5-284 Lapua brass which I neck turn to remove the donut that forms after expanding. A loaded round of this measures .311

I always remember reading that the 284 win doesn't like too tighter neck clearances.

In loading for both rifles I've always found that I cannot run the powder charges that I believe I should be able to in the barrel with the .317 neck.

I don't know if it's due to the lower neck clearance or the different lead angle.

Whereas the old M595 with the big sloppy neck has always been able to run the charges that Quickload tells me I can without seeing pressure signs too soon on a ladder.

My 284win is an ex tikka 20 inches 7mm 08 barrel with .322 neck. Work up to 53.3gn win760 powder with 162 eldx and Winchester brass, I only get 2690 fts which seems on a slow side of velocity lucky it is accurate. . @GWH If you can shine some lights on it I would much appreciate it.

Originally Posted by Rock

My 284win is an ex tikka 20 inches 7mm 08 barrel with .322 neck. Work up to 53.3gn win760 powder with 162 eldx and Winchester brass, I only get 2690 fts which seems on a slow side of velocity lucky it is accurate. . @GWH If you can shine some lights on it I would much appreciate it.

I ran mine at a very slow but very accurate 2650 fps with 162s and 2213sc. Still killed everything stone dead.

Originally Posted by Spitfire

I ran mine at a very slow but very accurate 2650 fps with 162s and 2213sc. Still killed everything stone dead.

What’s your longest kill with it? ��

Originally Posted by Spitfire

I ran mine at a very slow but very accurate 2650 fps with 162s and 2213sc. Still killed everything stone dead.

so it was doing what a .280 should do all day long without any fluffing around.......

Try RL17 or Superformance powder, u should get 150 fps with 160-162 gn pills

Originally Posted by chainsaw

Try RL17 or Superformance powder, u should get 150 fps with 160-162 gn pills

IMR 7828ssc also goes well in 284 with heavy for cal bullets.

I've tried all of the above in mine, got higher velocity with some but the grouping wasn't as good as my h414 load.

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Anyone tried the likes of H414 or Rel 17 with lighter projectiles like the 150 ELD-X or Berger 140 VLD for example?

Originally Posted by stagstalker

Anyone tried the likes of H414 or Rel 17 with lighter projectiles like the 150 ELD-X or Berger 140 VLD for example?

With the 150gr NBT I use to run in my 22 " 284 I only used a stiff charge of 2209, 2970 fps and shot really well.

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Originally Posted by stagstalker

Anyone tried the likes of H414 or Rel 17 with lighter projectiles like the 150 ELD-X or Berger 140 VLD for example?

Yup...3040fps using RL17 and the 140gn VLD. Thats with a 20" barrel.

Originally Posted by Kudu

Yup...3040fps using RL17 and the 140gn VLD. Thats with a 20" barrel.

@Kudu how did those 140s go up close at that speed? Still work alright on reds? Mine is 17” so would be a bit slower.

Originally Posted by stagstalker

@Kudu how did those 140s go up close at that speed? Still work alright on reds? Mine is 17” so would be a bit slower.

Mint. I'll send you a link when I get home to one of my videos that shows the damage they do.

Originally Posted by stagstalker

Anyone tried the likes of H414 or Rel 17 with lighter projectiles like the 150 ELD-X or Berger 140 VLD for example?

Two different 284’s with 150 ELDx and RL17.
22 bbl TF on Tikka sweet spot was 2980 fps
20 bbl on Weatherby MKV ultralight 2900 fps

7mm08 RL16 22in bbl 150 ELDx 2750 fps.