Advanced Armament Corps 300 Blackout Part 2

A long time ago, a good friend told me that the easiest way to stay on point when writing is to condense the objective of the work to a short sentence and keep that sentence in clear view when writing. So I did. No personal computers yet in existence, I taped each communication objective right there to the top of my IBM Selectric. Today that trick doesn’t work, because I am more interested in researching and learning. Subsequently, writing begins with an area of interest or curiosity and ends up where ever it ends up; usually with some answers and, typically, many more questions. The product brands aren’t really of consequence, other than as ingredients and how they perform in that respect.

Gas; nature’s invisible friend

The subject of gas and understanding of its uses seems to follow us through life. As children, gas is a component of a great offense/defense against siblings. Gas allows us to find adolescent humor in Shakespeare, “A man may break a word with you, sir; and words are but wind; Ay, and break it in your face, so he break it not behind” A Comedy of Errors. Understanding Boyle’s Law and Kinetic Theory prepares us for a career in plumbing, internal combustion engine intake and exhaust system design or propulsion sciences, depending on our bent.

With less case capacity than the 5.56 NATO, and nearly twice its bore volume, the 300 Blackout does not have sufficient gas volume production or pressure persistence to function reliably with a non-adjustable rifle or mid length gas system. On the other hand, the 300 Blackout is a little intense for a non-adjustable pistol length gas system and supersonic ammunition. A 16″ barrel seems to work well with a carbine length gas system in terms of performance, reliability and durability. In more quantified terms, I think it looks something like this –

While buffer weight and port size and placement can be balanced to accommodate different barrel lengths and gas systems, in general, pressure at the port increases as gas systems are shortened, as does muzzle pressure, as do secondary recoil and report. The AAC 300 Blackout MPW used for this project has a 16″ barrel and a carbine length gas system. It never failed to feed or eject and the bolt always stayed open when shot until empty with sub or supersonic factory ammunition or handloads.

300 Blackout handloading economics…

Handloading the 300 Blackout was straight forward and inexpensive. Good and appropriate bullets cost between 30¢ cents and 60¢ cents each, powder at today’s prices costs approximately 5¢, small rifle primers run 6¢, and brass casings 30¢ per round. Brass can be reused at least 4 – 6 times which puts the net cost per casing between 7.5¢ and 5¢. So the cost to produce handloads for the 300 Blackout is somewhere between $7 and $14.50 per twenty rounds. Commercially loaded recreational target ammo, supersonic 147 grain, is available through discount retailers for just about $9 for twenty rounds when purchased in 200 piece bulk, so being a handloader is not a prerequisite to inexpensive shooting.

Performance expectations….

SAAMI specs the 300 AAC Blackout with a Pmap of 55,000 PSI and assigns 16″ barrel bullet/velocity standards of 115 grain @ 2,270 fps, 123 grain@2,280 fps and a 220 grain bullet@1,020 fps. The 220 grain is defined as a subsonic standard, the others as supersonic.

After trying a number of flat based light weight bullets that I thought would work great, and found they did not, I settled on the bullets indicated on the table below as they performed the best. All were intended to be supersonic.

The Hornady 130 grain survived as the only flat base bullet, the rest are boat tail. Additionally, Sierra Match and Berger VLD bullets were selected because of their longish length. All bullets selected were verified as having plenty of rifling, magazine and bolt stroke clearance. All bullets were retained with neck tension and a Lee Factory Crimp die.

Warning: Bullet selections are specific, and loads are not valid with substitutions of different bullets of the same weight. Variations in bullet material and length will alter net case capacity,  pressure and velocity results. Primer selection is specific and primer types are not interchangeable. These data represents maximum loads in our firearms and test equipment and may easily be excessive in other applications. All loads should be reduced by 5%,  and developed following safe handloading practices as represented in established reloading manuals produced by component manufacturers. Presentation of these loads does not constitute a solicitation for their use, nor a recommendation.   Cartridge: 300 Blackout  Firearm:  Advanced Armament Corp MPW  Min – Max COL: 1.780″ – 2.260″  Bullet Diameter: 0.308″  Primer: CCI 450  Barrel: 16.00″  Reloading Dies: Lee Precision  Max case length: 1.368″  Groups: 3 Shots – 100 Yards SAAMI Specification and MAP 55,000 PSI

COL and Capacity   Load Data & Performance Bullet Type Bullet Weight C.O.L. Inches Net Grains Water   Powder Charge Grains Muzzle Chrono FPS Muzzle Energy Ft/Lbs 100 Yard Group Size “ Hornady #3020 SPFB 130 2.100 21.2   Alliant 2400 16.4 2128 1308 1.5 Hornady #3020 SPFB 130 2.100 21.2   Lil’ Gun 19.2 2315 1547 1.1 Hornady #3020 SPFB 130 2.100 21.2   Win 296 19.7 2281 1502 1.6 Sierra MatchKing #2123 HPBT 135 2.075 21.1   H110 18.5 2239 1503 1.1 Sierra MatchKing #2123 HPBT 135 2.075 21.1   Lil’ Gun 18.0 2237 1500 0.9 Sierra MatchKing #2123 HPBT 135 2.075 21.1   Win 296 18.3 2211 1471 0.7 Berger VLD #30510 HPBT 168 2.260 18.5   H110 16.2 1873 1309 0.7 Berger VLD #30510 HPBT 168 2.260 18.5   Lil’ Gun 15.8 1938 1401 0.4 Berger VLD #30510 HPBT 168 2.260 18.5   Win 296 16.2 1881 1320 0.9 Berger VLD #30512 HPBT 175 2.260 18.2   H110 15.9 1848 1327 0.9 Berger VLD #30512 HPBT 175 2.260 18.2   Lil’ Gun 15.2 1851 1332 0.6 Berger VLD #30512 HPBT 175 2.260 18.2   Win 296 16.0 1836 1310 1.1 Jamison JHP 125 – –   Factory – 2054 1171 0.5 Remington OTM 220 – –   Factory – 1136 631 1.0

Accuracy was good. I thought factory ammo performance was stellar and the weight spread didn’t reflect the MPW’s preference for either. Lil’ Gun loads ran a bit warm. This very light firearm’s recoil and muzzle jump were minimal Factory round targets pictured left.

IMR4227 was tried without much success in terms of velocity or accuracy. Alliant 2400 delivered about the same level of performance. No powder used seemed optimal. H110 works great for 45 Colt performance loads when it fills a case to compression. It was not possible to reach full case loads with the 300 Blackout. Seating bullets more deeply to get close to a case full reduced velocity and accuracy. The only powder types that came close to filling the case lacked energy; full case, low velocity.

The 300 Blackout cartridge is an interesting performer, but not so much in comparison to other more mundane firearms I use on a routine basis for recreational target practice and for small and medium game hunting.

223 Remington 55 Grain 24″ Barrel
Yards	0	50	100	150	200	250	300
Velocity – fps	3200	3007	2822	2644	2472	2308	2150
Energy – ft.-lbs.	1250	1104	972	853	746	650	564
Path – in.	-1.5	1.0	2.5	3.0	2.2	-0.1	-3.9

Best Zero Results
Near Zero -Yards	28	Midrange -Yards	144
Far Zero -Yards	249	Max Ordinate “	+3.0
Point Blank -Yards	290	–	–

 

300 Blackout 135 Grain 16″ Barrel
Yards	0	50	100	150	200	250	300
Velocity – fps	2239	2136	2036	1939	1845	1754	1665
Energy – ft.-lbs.	1502	1368	1243	1127	1020	922	831
Path – in.	-1.5	1.7	3.0	2.2	-1.0	-6.6	-15.1

Best Zero Results
Near Zero -Yards	20	Midrange -Yards	106
Far Zero -Yards	188	Max Ordinate “	+3.0
Point Blank -Yards	221	–	–

 

30-30 WCF 20″ barrel
Yards	0	50	100	150	200	250	300
Velocity – fps	2300	2177	2058	1943	1831	1724	1622
Energy – ft.-lbs.	1879	1683	1504	1340	1191	1056	934
Path – in.	-1.5	1.6	3.0	2.2	-0.8	-6.5	-15.0

Best Zero Results
Near Zero -Yards	20	Midrange -Yards	108
Far Zero -Yards	190	Max Ordinate “	+3.0
Point Blank -Yards	222	–	–

 

260 Remington Berger 140 VLD 20″ Barrel
Yards	0	50	100	150	200	250	300
Velocity – fps	2685	2614	2544	2475	2408	2341	2276
Energy – ft.-lbs.	2241	2124	2012	1904	1802	1703	1610
Path – in.	-1.5	1.3	2.8	2.9	1.6	-1.2	-5.5

Best Zero Results
Near Zero -Yards	24	Midrange -Yards	130
Far Zero -Yards	232	Max Ordinate “	+3.0
Point Blank -Yards	273	–	–

Conclusions?

The usefulness of a firearm/cartridge combination is tied directly to its owner’s applications. If I needed to boost the power of a 5.56 NATO AR at a minimal cost, the 300 Blackout would fit well. If a subsonic, suppressed round was important, again, the 300 Blackout would be a good fit. If high magazine capacity and low ammunition weight were considerations, the same would apply. The 300 Blackout has many unique special circumstance qualities, but for hunting… hogs, deer, black bear, my applications, there are many better. I am not suggesting the 300 Blackout is an inferior cartridge, but I am saying I can’t think where it would be a good fit for me.

Advanced Armament Corps 300 Blackout Part 1
Advanced Armament Corps 300 Blackout Part 2