Straight 284 in an AR platform

[joker7940]

Is there any one out there that shoots a straight 284 in an AR platform? I'm looking for actual shooters that have a rifle and shoot it or shot it to lend some pearls of wisdom. I had brux already make me a barrel for a dpms LR-308 style receiver and want some ideas for the perfect build. If you wouldn't mind letting me know some of your set up details so I can help mine along. Such as:
Gas block, if adj which?
Receiver make
Load restrictions
Feeding probs if any
Etc.

Thanks everyone!

 

[FCS]

Re: Straight 284 in an AR platform?

http://www.snipershide.com/forum/ubbthre...100#Post1992100

Info you've requested in link above

 

[joker7940]

Re: Straight 284 in an AR platform?

Thanks FCS I saw that post most everyone was a nay sayer to the idea or just speculated. No one actually had a rifle.
Some suggested the 7 Saum but according to ar-10rifles.com the pressures were a little high with the AR and they were literally blowing through extractors. I even asked if they would build me one they declined because one they built is coming back to their shop every couple of months for problems. The saum was my first choice before that conversation. In fact I can't even find a saum bolt for a build and they won't sell any with out a rifle or upper.
I also understand mag length will be an issue for the super long range loads 180 bergers etc but the semi option for the ~150 gn bullets would be great with a mag cap with 10 or more makes having a semi too nice.
The barrel I had built is a 30" 4 groove 1/8.5" twist the gas block extended 2" past rifle length. I will have an adj gas block so it can be completely turned off for the long shooting so that magical 150+ fps you lose with a gas gun doesn't literally blow back into your face. Making it possible to be able to take full advantage of the big 180 gn 7mm bullets out to 2900 fps.

 

[bustin]

Re: Straight 284 in an AR platform?

I built a bunch of ARs with mag cartridges a few years ago but, DPMS and Armalite stopped making RSAUM bolts and extractors for a reason. The big cases don't feed well, the extractors break, the high pressure cartridges make the cases stick to the wall of the chamber which rips the rims off or breaks the extractors. I thought it would be a great idea in the beginning, good luck.

 

[Mike_in_FL]

Re: Straight 284 in an AR platform?

This is a bolt gun build in .284. It has some interesting reading on OAL on this cartridge.

http://www.6mmbr.com/gunweek095.html

 

[joker7940]

Re: Straight 284 in an AR platform?

Looks like I might be on my own with this then. Thanks for the help guys. When I get it built I will give a full range report.

 

[FCS]

Re: Straight 284 in an AR platform?

Having done a 243AI and a rebated rim 300WSM on AR platform....I'd not do either again as both were a PITA to get running smoothly.

7-08 in AR platform is going to be much easier to get running and when all said n done the difference you could get from a 284 case is going to be minimal.

Your $, you can do as you want.

If you do go ahead with the project, be interesting to read the range report.

 

[AMMOWASTER]

Re: Straight 284 in an AR platform?

While not a auto my friend recently built his savage in 284 with the main purpose to be mag fed.

He was saying just the other day he would probably just do 7-08 if he were to do it over again.

Good luck with your build. I am interested in seeing how the Brux shoots

 

[joker7940]

Re: Straight 284 in an AR platform?

Ya guys I guess I should have clarified this in the first place. The mag feeding is a secondary point, primary is getting a 7mm bullet at least 2900 fps with out over pressure issues. Thats why I stepped away from the 7mm-08 the boys at 6mmbr.com voiced that the 7mm-08 couldn't get a 180gn bullet going 2900 fps (well that is with out some serious problems). I picked the 284 for case cap and design its basically an AI cartridge with out the true designation of AI. Fitting in 308 mags with some mods to the lips makes it even better. With adj gas block, 30" barrel, and RL17 2900 shouldn't be an issue. Then varmint days load some 120 gn v-maxs to mag length or maybe a 120 or 140 gn nosler and have some fun with the semi.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AMMOWASTER</div><div class="ubbcode-body">Good luck with your build. I am interested in seeing how the Brux shoots</div></div>
I have a 28" chambered in the grendel from brux and it is the most accurate set up I have without question. 2.5" (consistent) groups at 500 yds all day long. I shoot it way more than my 308 now. The range report might have to wait until november my BA50 comes next week so that will draw my attention away for a few weeks!

 

[Falar]

Re: Straight 284 in an AR platform?

If you can't feed from the mag than why even bother with an AR?

 

[BOLTRIPPER]

Re: Straight 284 in an AR platform?

while you are at it ....make it a lefty

 

[joker7940]

Re: Straight 284 in an AR platform?

It can feed from the mag with smaller bullets but the LR loads ie 180 gn berger VLD or equal will never be mag fed for short action rifles whether they are a bolt or a semi. Unless the bullet is halfway down the case, then at that point you might as well get a laser pointer because that is the only thing that will let you make a mark at 1500 yds. The same goes with most cases that fill the mag normally. Hell my 308 with the 178 gn amax is no where near mag length if I want a full case of powder. So it becomes a single shot. Try stuffing a round loaded with a 750 gn amax or 815 gn bore rider down a M107 mag. Not happening. Doesn't mean you can't shoot ball from the mag. It just means you can't shoot the lr good stuff from a mag generally speaking.