Sunday, February 27, 2011

.30 Remington AR

A recent article in "American Rifleman" on the cartridge really brought this cartridge to my attention.  I know I'm about 2-3 years late to the game but I've had a lot on my plate and let's face it, the AR platform isn't a major interest to me, or hasn't been (more on that in a later post).   I had previously been considering the 7.62x29 COMBLOC round as a larger caliber, "more" capable round for my AR15 carbine.  I abandoned that interest because I was told that the magazines were problematic.  I had considered the .300 Whisper but it was designed primarily as a silenced round with the alternative use of the light bullets at speeds less than the 150s in the .30 AR.  In short, not enough gun.  Perhaps the .30 Rem AR is a cartridge that could fulfill the uses I foresaw for the platform.

I do have some concerns.  First and foremost, will I be able to simply swap an upper for the cartridge onto my current lower or will it require a whole new rifle?  Second, will it be difficult to find magazines that will work with the cartridge?  I would rather not complicate the magazine situation and ideally I'd like to use 5.56 magazines.  Last, and these are all critical concerns, how available will brass for the cartridge be?  If you can't get brass the whole point is moot.  Of course there are other concerns, such as with appropriate bullets, ballistic performance, appropriate powders and primers, and so forth, but most problems with such concerns can be overcome or adaptations made.

Some background on the cartridge is called for here. Remington's engineers started with the .450 Bushmaster case, a joint project between Hornady and Bushmaster. The magazine depth (front to back) is the limiting factor in cartridge overall length (COL). A .30 cal bullet of usable weight being longer than the .458" bullet, the case had to be shortened from the original length of 1.700" to 1.530". The case head is the same size as the .308 Winchester. Due to the increased pressures of the .30 AR over the .450 Bushmaster Remington engineers used an AR-10 bolt head. Clearly, this is one change that might affect other things in the system. However, Remington increased the RIM diameter to .492". This was to prevent use of the .30 AR cartridge with a .450 Bushmaster bolt head which is considered to fragile to contain the much higher pressures of the .30 AR cartridge. With a case head of .500" we have a short REBATED rim case. Remington has this to say about their new cartridge.
Now for the first time, Remington® brings you 30 caliber hunting performance in a lightweight R-15 modular repeating rifle. Our new 30 Remington® AR cartridge produces big-game-dropping ballistics similar to the venerable 308 Win. with pressures perfectly suited to our lightweight R-15 platform. Comparable terminal power was once only available in the heavier AR-10 platform.

This cartridge is the ultimate synergy of our ammunition and firearms expertise, as its development forever changes the shape of both categories, creating a revolutionary new big-game hunting system. Our lightweight R-15 platform – its minimal recoil, rapid follow-ups, easy maintenance and inherent accuracy – chambered for a cartridge that will put down deer-sized game with gusto. This year’s offerings include the most trusted big-game bullet of all time, Core-Lokt, the pinnacle of polymer-tipped accuracy, AccuTip and an economical UMC loading. As a cartridge, the 30 Remington AR breaks new ground. In conjunction with our R-15 modular repeating rifle, it marks the beginning of a new era in the deer woods of North America.

.308 Win, .30 Rem AR and 5.56mm NATO compared
Case capacity is 44 gr. of water by weight. This is roughly the same as the .30 WCF (.30-30) but of course the .30 AR operates at much higher pressures so exceeds the velocities of the old .30 by quite a bit. However, this is much less than the capacity of the .308 Winchester (about 53 gr.) and it operates at less pressure than the .308 Winchester so there is no way it can equal that cartridge. In other words, you can't equal the M14 on the AR15 platform. You can see how the two cartridges compare in the chart on the right. It does appear that there is a useful improvement in terminal ballistics compared to the 5.56mm cartridge, at least for my purposes.  In my reading on the subject I see one common thought repeated and that is that a .30 WSSM cartridge (does Olympic still support this?) would be a better "fit" and provide better ballistics.

Is the upper installation a simple swap? The answer is yes! That is a big relief as this greatly reduces the cost of getting into the cartridge. Unfortunately it still isn't "cheap" in this regard with the least expensive upper asking $737.00 plus shipping for an A3 style flattop upper. I would personally prefer an A4 type upper.

Are magazines available? One of the concerns is that capacity is severely reduced being about 40% of that of AR-15 magazines. I.e. a 4 round mag is reported to be about the same size as the 10 round 5.56mm magazine.   Well come to find out that one simply uses the 5.56 magazines and just as with the WSSM cartridges, 4 rounds will go in a 10 round mag.  This means that the magazines simply don't have the capacity to make the rifle useful for tactical applications.  That is a possible secondary use for me.   I have read that the magazines for the WSSM cartridges must be slightly modified but I can find no reference to such requirement for .30 Remington AR usage.

Is brass and/or ammunition available? I can find ammo with CoreLokt going at about $20.00 a box but switch to the Accutip bullet and that nearly doubles to about $38.00 a box of 20 rounds. If you're going to reload, the RCBS die set (RCBS dies are usually close to the high average of all available dies in price) is available from MidwayUSA for $52.79. However, I couldn't find brass anywhere! Not only is this bad for the reloader or handloader (me) but it really raises the cost of acquiring sufficient ammunition to make use of this cartridge a viable alternative. I could find 6.8mm SPC and 6.5mm Grendel brass that makes them eminently more useful to me.  One has to wonder why Remington is not supporting the cartridge by getting brass out into the market.  For me, no brass means the rifle is of no use.

Links:
- .30 Remington AR by Layne Simpson
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