Thread: . 284 Winchester

Originally Posted by chainsaw

Interesting comps @Puffin on 284 vs 280ai - my real word experience aligns closely with the QL model data but with different powders needed to get optimal results. I did a lot of background research into 284 vs 280ai and initially went with 280ai as an “alpine tops rifle”. Partly due to higher top end potential in fps & that partly due to fact that published load data on 284 is scant and very conservative. Anyhooo 1st built a 280ai 24in bbl on REM700 action – load dev eventually ended up with N560 pushing 162 AMAX at 2980 fps. Have also built several 284’s - 2 with 20in bbls giving 2830 – 2850 fps with 160 TMK’s using RL17 or Superformance. And a 284 with 22in bbl that runs 2930 fps with RL17 pushing 162 AMAX’s.
In all cases these loads were not at pressure “max”, but at safe loads giving sub 0.5moa grps – generally a smidge under where pressure signs started showing up.
Yes, the 280ai has the edge but not by much and you really need to stay with a 24in or longer bbl to ring the max out of them, imo.
The 284 cartridge is inherently very efficient and certainly punches above its weight. If you’re after a shorter bbl 7mm for bush bashing then its ticks all the boxes, just be realistic about the drop in speed potential once you chop the bbl

@chainsaw I wonder if you could be so kind as to PM me your R17 loads for @craigc. Of course we understand that we will need to start a few grains under your load. 22" barrel using 162AMAX and 150 ELDX. We are fortunate that we have a few pots of R17.

@Tahr - will do.

I find it passingly strange that when talking .284 calibre the .280 in particular is often made into AI form and spouted as the ducks nuts,yet Im begiggered if Ive heard of anyone that I can recall creating a .270AI........maybe its a case of not mucking around with a good thing LOL.

Originally Posted by Micky Duck

I find it passingly strange that when talking .284 calibre the .280 in particular is often made into AI form and spouted as the ducks nuts,yet Im begiggered if Ive heard of anyone that I can recall creating a .270AI........maybe its a case of not mucking around with a good thing LOL.

It's because only fudds are interested in the 270 and AIing a cartridge is beyond them.

Some very interesting comparisons puffin. If we are comparing the improved version of the .280, perhaps we should compare it to the .284 Shehane? I think your figures show that the .284 is pretty efficient. I spent a lot of time reading before I decided on mine.

Either way, both are great all-rounders for all NZ game.

I've got a couple of 284 wins.

Both rechambered tikka 708s.

One is a T3 cut to 17" with DPT magnum suppressor. Long mag and bolt stop.

The barrel was throated long to suit 162s seated out in the neck.

I run 162 Amaxs at around 2700 fps which kills really well near and far. I use H414 powder.

The other one is an older tikka M595 with a factory length 22" barrel. Also throated long.

I always just use to run 150gr NBT to fit the fairy short magazine at just shy of 3k which worked really well.

I've recently fitted a T2 brake to this barrel and am experimenting with 180gr eld-m's.

They shoot super well with IMR 7828ssc at 2760 fps.

But have just this morning shot a ladder using RE26.

These are the results.

They're getting along pretty well.

56gr 2789 fps
56.5. 2820
57. 2841
57.5. 2859
58. 2869
58.5 2906 (click at top of bolt lift and very flat primer)

Looks like it's going to group well in the middle of the range around 2850 fps.

Run the numbers on the 180 eldm at that speed, pretty awesome performance from a 22" 284.

My chamber has a very long throat and I can seat the 180s out nice and long. COAL of 3.257 inch.

Don't go trying these loads with a shorter throated barrel. Start lower and work up.

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Interesting that you wound up on 58 grains of RE26. I’m on 58 grains of 2213SC at 2840 fps from a 22” barrel with 162 ELD-X. I have some RE26 and 180 ELD-Ms on hand, but that’s what I’m shooting out of my 7RM.

Originally Posted by GWH

I've got a couple of 284 wins.

Both rechambered tikka 708s.

One is a T3 cut to 17" with DPT magnum suppressor. Long mag and bolt stop.

The barrel was throated long to suit 162s seated out in the neck.

I run 162 Amaxs at around 2700 fps which kills really well near and far. I use H414 powder.

The other one is an older tikka M595 with a factory length 22" barrel. Also throated long.

I always just use to run 150gr NBT to fit the fairy short magazine at just shy of 3k which worked really well.

I've recently fitted a T2 brake to this barrel and am experimenting with 180gr eld-m's.

They shoot super well with IMR 7828ssc at 2760 fps.

But have just this morning shot a ladder using RE26.

These are the results.

They're getting along pretty well.

56gr 2789 fps
56.5. 2820
57. 2841
57.5. 2859
58. 2869
58.5 2906 (click at top of bolt lift and very flat primer)

Looks like it's going to group well in the middle of the range around 2850 fps.

Run the numbers on the 180 eldm at that speed, pretty awesome performance from a 22" 284.

My chamber has a very long throat and I can seat the 180s out nice and long. COAL of 3.257 inch.

Don't go trying these loads with a shorter throated barrel. Start lower and work up.

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Fuck that's impressive speed/ballistics. What twist rate? Standard 1:9.5 tikka?

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Originally Posted by Nick-D

Fuck that's impressive speed/ballistics. What twist rate? Standard 1:9.5 tikka?

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Agreed, my mate is just a touch over 3000fps from a 28" barrel using RL17.

Originally Posted by Nick-D

Fuck that's impressive speed/ballistics. What twist rate? Standard 1:9.5 tikka?

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Yes factory 9.5 twist tikka barrel.

Yeah the velocity and corresponding ballistics with that bullet are certainly quite impressive from the humble little 284 and 22 inch tube.

It certainly gives the 284 some legs.

Crazy stuff!

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There must be something to these tikka 9.5 twist barrels.
This is the results of my dabble with the 180 eldm's in my 7mm08ai

Load development



And a group at 600yds with the chosen load doing 2650fps

Originally Posted by wsm junkie

There must be something to these tikka 9.5 twist barrels.
This is the results of my dabble with the 180 eldm's in my 7mm08ai

Load development

Attachment 129941

And a group at 600yds with the chosen load doing 2650fps

Attachment 129942

What powder you using for that one? I have a Tikka t3 7mm08 as well and I've only tried the 162 eldm with 2208, awesome accuracy at 2600 fps. Always Keen to try new things haha

Originally Posted by Rated M for Magnum

What powder you using for that one? I have a Tikka t3 7mm08 as well and I've only tried the 162 eldm with 2208, awesome accuracy at 2600 fps. Always Keen to try new things haha

AR2209

Originally Posted by Rated M for Magnum

What powder you using for that one? I have a Tikka t3 7mm08 as well and I've only tried the 162 eldm with 2208, awesome accuracy at 2600 fps. Always Keen to try new things haha

2209 should give you a bit more velocity with 162s than 2208 I would think.

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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.