RELOADING
6.8 SPC
Designed for an AR platform, this short “.270” is a deer/varmint double threat.
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This cartridge, which first appeared in civilian clothes in about 2004, allowed the M16 to be converted by simply replacing the top end. The acronym “SPC,” incidentally, stands for “Special Purpose Carbine.” It supplies more punch and reach than the ubiquitous 7.62x39 while still being mild enough to fulfill the assault rifle application—that is, to allow controlled full-automatic fire.
Several manufacturers are loading 6.8 Remington SPC ammo for civilian sale. The case is a shortened variation on the .30 Remington case that was introduced in 1906 and is now thoroughly obsolete in that form. The newly manufactured cases present an interesting problem. Cases manufactured by Remington use large rifle primers, while those made by Hornady (and others) use small rifle primers.
It’s not a serious problem if you are aware that the difference exists. Someone starting to load for this cartridge would be well advised to select cases that use either the small or the large primers, then stick to that type only. In my tests I used both types of primers (in the appropriate cases, of course) and couldn’t really see any difference in actual performance.
There are more than enough bullets available to cover your shooting and reloading needs. And don’t let that metric designation fool you. The 6.8 is really the good old .270. That’s good, because .270 bullets have been around for a long time. The useful ones are all at the light end of the .270s and range from 80 grains up to about 130 grains. Beyond 130 grains, the bullets are so long that if they are loaded to the maximum overall length allowed by the magazine length, the base of the bullet intrudes too deeply into the case and uses up too much of the available propellant volume. The result? Less than optimum performance.
Primer availability is no problem, but as we’ve mentioned above, you need to know which size your cases require. There is no shortage of suitable powder, but the small case limits the selection to the faster numbers in the rifle list. A gentleman who has been loading for the 6.8 for quite some time told me that he had decided that Hodgdon’s 322 was the best overall choice. That powder worked well in my tests (see table), but there were a number of others that were equally useful.
The particular load referenced in the table using IMR 3031 is there to illustrate what happens when too bulky a powder is used. The case is filled before you get up to the performance obtained with “better” powder choices.
It used to be that most all bullets had similar-weight jackets. That allowed brands to be interchanged without much of a problem. Modern high-performance bullets are made with jacket weights that are wildly different from one brand to the next. While you can interchange any of the starting loads for the 130-grain bullets shown in the table, the maximum loads apply only to that specific bullet construction. Note that even different-style bullets from the same manufacturer show different results. As always, when changing anything, begin with the starting load and build up gradually and carefully in small increments while watching closely for any signs of trouble.
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