280ai vs 284 Winchester

Timnterra

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I'm building a super lightweight mountain hunting rifle and because of the ammo shortage I'm starting to question my caliber choice. I was firmly set on the 280ai but I can't find a piece of 280ai brass anywhere. I don't have dies and they are providing hard to find too. I am starting to lean towards the old 284 Winchester. Good quality Brass seems to be available from Norma, Peterson and lapua and for some reason it's in stock. The dies are in stock too. Here's the question. I've never shot a 284, I've had a 6.5-284 but never a 284. I don't know what kind of performance I can expect. The rifle will be built on a long action either way so I will have extra room for the 284 to breathe. What kind of performance difference should I expect between the two out of a 22" barrel with 160 class bullets?
 

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Both are great cartridges. I was always going to build a 280ai and had not considered a 284 until a friend of mine that shoots F-class (600 and 1000) switched from 7 saum to 284. I am a bench rest shooter but not an F-class competitor. I tend to keep my hunting rifles in the 24" or less for barrel length and for my Black Hills rifles I try to stay in the 22" range. I sacrifice the bit of velocity for the ease of handling. I like your thinking on the 22" barrel. At that length and 160 gr. bullets, the difference between the two cartridges is negligible. You just burn less powder to reach the virtual same velocity. I like building rifles with cartridges (and variants) that will use Lapua brass. With that said, I exist in the realm of the bench rest psychosis of neck turning, and all the rest that goes with that world. Analysis paralysis. But I love my 284 win.
 
I have a .284 chambered with the .284 Norma Match reamer. I use Peterson brass, RL23, and 175gr Berger's and get 2840-2850 with a mild load and a 26" barrel. The .280 AI and the .284 are going to be very similar in performance. The .280 Ackley will edge it out by 50-80fps with top level loads. My vote is for the .284 though. More premium brass available and it's usually in stock along with the dies.
 
Capacity-wise, 284 Win is basically a .280 Rem, so ~75fps.

The cool thing about the 284 is it fits an 'intermediate' action really nicely.

If you are planning to run heavies (175 or 180gr), overall cartridge length and magazine box length require careful consideration. A .280AI will be hamstrung running at 3.34", a .284win wil be hamstrung running at 2.86"
 
Good point on the reamer and brass posted by Jud96! There are a couple differences in the body sizes that exist. Be sure that you match your brass(Norma, Lapua vs. Win style) with your reamer design. I designed my reamer based on the Lapua (6.5-284) brass. I haven't used the Peterson brass yet so I can't comment on the size relation with it. If you haven't tried or researched the Hammer bullets, they are outstanding and warrant serious consideration. I am not associated with the company, just have used them on game. The 143 Hammer performs like a larger weight projectile. Their design is close to the best of both worlds when it comes to short and longer range bullet performance.
 
Wish I could help but I haven't shot my 284 yet. It's got a 24" benchmark. Just ordered 100 of the 140 absolute hammers to try. I'm limited to length as it's a short action. Has a Wyatt extended box at 2.995" I believe. Putting together a 280AI as well to shoot the 154 dead blow hammer. Guess I was lucky here in Canada. First call and I had 100 pieces of Peterson 280AI brass ordered. Should be here tomorrow. For reference guys are getting over 3300 FPS with a 140 AH out of 280AI and 22" barrels.
 
I've used a light weight 284 Win for 10 years or so, and I like it.
Not what OP asked, but for West Texas last season I was loading 130 CEB MTH bullets at safe and accurate 3200FPS.
Mine scoped/sling 6lb 4 oz on a short action Rem TI action.
That said, I've just ordered parts and components for 280 AI. Don't need it to do better, just different.
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What action? Mag length? Built 2 284s. 26' and 20". Very accurate cartridge, obviously by it's F-class record. Not sure how many records it broke and championships it won
 
Cajon makes a great point in that the early 284's were built for old short action magazine Winchesters and the like. But guys are building them on mid actions (Tikka) and on long actions (Rem) now to seat the bullets out of the case. This fact as well as a larger body diameter, steeper shoulder angle (better burn efficiency), but still keeping rim size the same as 308/30-06, is producing awesome potential for a cartridge. As for the F-class, the barrels are lasting quite a bit longer than short mags or 6.5-284 from what I hear. Not as big of a concern for hunting rigs.
 
I've used a light weight 284 Win for 10 years or so, and I like it.
Not what OP asked, but for West Texas last season I was loading 130 CEB MTH bullets at safe and accurate 3200FPS.
Mine scoped/sling 6lb 4 oz on a short action Rem TI action.
That said, I've just ordered parts and components for 280 AI. Don't need it to do better, just different.
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I really like the setup you have there, who did the milling work for the action?
 
Have owned rifles chambered in 284 Win since 1983. Have rebarreled the original SA Ruger several times. Had mag box lengthened to accept a loaded round with an OAL of 3.050". Own a custom reamer with a .317" neck requires a bit of neck turning. Throat is a 1 degree 30 min angle and is setup for the 168 VLD to engage lands .010". Current barrel is 23" long, a rechambered Rem 700 7-08.

Recently acquired a LA Rem also chambered in 284 Win with a .3165" neck also a 1 1/2 degree throat angle. Use same setup with my K and N neck turning tool. This one has a 28.5" 1 in 7 3 groove lilja and shoots 180 berger target hybrids into bugholes.

Best results will be with H4350 or if you want a bit more velocity, RL-17.

LA Rem 284: 180 target hybrid and 52 gr of RL-17 2800 fps

Currently SA 284:

168 Berger VLD and RL-17: : 52 gr RL-17 fed 210 match brass neck turned for .310" neck OD Reamer neck .317" Loaded ammo is .310" velocity 2925 fps
120 Nosler ballistic tip and RL-17: 58 gr of RL-17 3457 fps. seated bullet without changing seater die setup that was used with 168 VLD.



Generally you can get 3000 fps with a 140 57 gr H4350 and 2900 with 52-54 grs H4350 with a160 gr bullet using a standard SA magazine length around 2.85" or so. Or way back when it didn't exist IMR 4350.

Bob Hutton and Fred Huntington played with this cartridge when it first came out in 1963. Their pet load was 57 or 58 gr of IMR 4350 with a 140 partition for velocity around 3000 fps.



Anyone reading this should realize every firearm is different in what it can safely handle. Please work up with care.




TiminTerra PM me for specific load with a variety of bullets.
 
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