284 win AR born again

[stagpanther]

I built a 284 win AR some years ago and was looking around for it but couldn't find it--I thought maybe I'd lost it or worse yet maybe it was stolen. I finally found the barrel in the barrel rack and couldn't for the life of me remember why I had taken it apart--other than the short action limitations of an AR and not stacking well in a 308 magazine-- I remember it shot very well. I reassembled the rifle around spare parts that I had, definitely an indignant franken-build compared to the original incarnation. Lesson learned--if your rifle shoots well--don't part it out. Hopefully it still shoots well.

 

[Recycled bullet]

That's really cool! Are you handloading for it?

 

[stagpanther]

Yes. I actually built it originally about 5 years ago--but took it apart probably because I was hot to put something else together and needed the parts. Had enough spare parts to put it back together. Of course I'll need to seat bullets deeper than I would in a long action and will be limited in COL--but it shot very well as I recall.

 

[jetinteriorguy]

I like that stock, what is it?

 

[stagpanther]

Strike Industries modular rifle stock. Magpul's is cheaper and does the same thing, though not quite as adaptable. I like em cause they are minimalist (I don't like slapping doodads on my ARs) inexpensive and rigid.

 

[RC20]

Taking apart a good shooting rifle is like jumping out of a perfectly good working airplane.

 

[stagpanther]

Taking apart a good shooting rifle is like jumping out of a perfectly good working airplane.

That's true. On the other hand, I just found out why I probably took it apart. No matter how much effort I put into it--I still can't get a magazine--and believe me I've tried modifying almost a dozen of them--to cycle more than 3 cartridges. If there ever was a case design made to NOT work in an AR magazine--the 284 is it. I have succeeded in getting very good groupings with it--and with some finagling managed to get COLs out to 2.96" +/- but the case has a couple of seemingly insurmountable obstacles. The tapered body and rebated rim cause enormous headaches in stacking properly in a magazine, they swell the magazine to the point you can get only a few in before they jam. The rebated rims are prone to hooking on one another due in part to the large rim groove, and this can cause the bolt to miss picking up the cartridge or fail to lock back when the follower is tilted--hard to avoid when the feed lips have to be trimmed back and the follower needs to tilt a bit in order to get a successful feed to the chamber. I don't have the tooling or engineering expertise to make my own magazines, but increasingly I think a viable answer lies in making a single-stack design--similar to the Tromix single-stack set-up for 458 SOCOM.

Ultimately, I think the real failure of the 284 win in ARs is due simply to short-action performance limitations imposed by the original design for 2.8" COL. It is a great cartridge design with much performance potential--but only when using a bolt action whose magazine and freebore allows the COL to go way beyond 2.8" However, when you think about it, the 7.62 x 51 has the same limitations and that has not prevented it or its spawn from becoming wildly successful in ARs.

 

[stagpanther]

another try...

Sorta last gasp effort--I was resigned to taking the gun apart again--but then tried an experiment on an old Brownells mag. They are among the simplest and cheapest out there--but I've found them to be one of the versatile as well. My goal is if I can get 5 successive shots with no functional issues--then it's worth keeping together.

I tried two new things today, I put a couple of layers tape on the inside ribs to narrow the profile of the magazine (temporary adjustment) and I also sanded in a taper towards the outside of the magazine on the top of the follower--this seemed to counteract the propensity for the cartridges to "toe" inward and then cause other issues with rims hooking and the cartridge tilting so that the bolt failed to catch them. I also did a front cut-out which allows a COL of about 2.925" and still cycle no problem. This should theoretically get me around 3,000 fps with a 150 gr bullet out of my AR.

I loaded up some 162 gr sst's seated to nearly 2.93" to test today and found that the magazine still swelled--but allowed me to get 4 cartridges in with no issues. Thus, with one pre-loaded into the chamber I could get 5 consecutive shots off.

I'm happy to say that everything worked perfectly (at least for this outing) no hang ups or jams and normal lock-back of bolt upon the last shot. So now I'm back in the "maybe this has practical hope after all mode.

 

[rickyrick]

You’ve put together some pretty interesting ARs over the years, makes me wanna try new stuff, but then it scares me haha.

 

[stagpanther]

You’ve put together some pretty interesting ARs over the years, makes me wanna try new stuff, but then it scares me haha.

Sometimes I think I have more fun putting them together than shooting them. But reloading gets me over that hump.

The guy on this forum who built a 375 H&H AR from scratch--now THAT's impressive!

 

[stagpanther]

Rather than mess around with smaller bullets I've decided to go straight to the "acid test" for 284 win viability--berger 180 gr hybrid targets. Although shorter barrel and COLs will have a negative impact, I'm still interested to see how well they can work in an AR.

 

[stagpanther]

Got to shoot the two test loads using the 180 gr bergers this morning; I think I can sum up the results as "so much for that fantasy." SD and ED figures were awful, and the best I could do was just above 2,500 fps even though I was only 2 grains off from maximum pressure charge weights using H4350 and the barrel, while not ideal in length, is still a 24" barrel.