Gunner Quinn
(Continued from Part 3.)
Suggested Low-Cost Replacement Parts
Here are some suggested low-cost spares/replacement parts, available from Palmetto Stae Armory (PSA):
PSA Classic Lower Parts Kit, FDE
PSA AR-15 Bolt Carrier Group 5.56 Full-Auto Nitride MPI – 516446953 $69.99
Everything but the lower receiver and parts associated with the lower half that includes the butt stock:
PSA AR-15 Upper 5.56 16″ Carbine-Lgth 1:7 M4 Nitride MOE w/ Rear MBUS, BCG, & Charging Handle, $319.99
This might be the lowest-cost way to acquire all the replacement parts without buying an entire rifle. This blemished build kit has everything except the lower receiver:
BLEM PSA Freedom AR-15 Rifle Kit 5.56 16″ M4 Carbine-Lgth 1:7 Nitride – 507617B $299.99
Barrel Life
Garand Thumb did an impressive test of the PSA barrel to failure. He documented on video the barrel’s performance and longevity during an exhaustive multi-thousand-round test. See: How Many Rounds Will A 400 Dollar AR-15 Last? A PSA barrel lost it’s accuracy after about 5,000 rounds. Had slower firing testing been used, instead of the full auto magazine dump method, the barrel may have lasted much longer. But this is a valid test because it simulates hard use on a battlefield and is compared to the performance of premium rifles tested under similar methods. Fortunately, PSA rifles and parts are good enough and the cost is very low given their performance. PSA has the best price-to-performance ratio that is well-tested and reviewed. PSA’s parts are not the best, but they are good enough and there is a huge advantage to buying multiple copies from PSA. We can buy 2 to 4 examples for the same money spent on a single high-quality rifle. But we should understand the weak points and prepare accordingly. Buying complete spare uppers is the lowest cost and most practical for most people who are not gunsmiths or hobbyists who can replace parts.
Replacement AR-15 Uppers
If you rather not go through an FFL, this is an inexpensive way to go that also expands your rifle’s capability. The plethora of complete uppers of various lengths and chambered in various cartridges and make choosing a barrel fun and confusing. I prefer the 5.56 NATO chambers because there is only a bit more accuracy to be had with the Wylder chamber, but there is a significant improvement in reliability if the 5.56NATO chamber is used in battlefield conditions. Dirt and carbon build up + heat that burns off lubrication = lack of lubrication and stuck cases. If you have a stuck case, then odds are the rifle will be inoperable until the stuck case can be removed with a tool made for removing it or if a cleaning rod can punch it out. Posting the rifle may clear it. Or it may not.
The 5.56 NATO chamber was designed and tested over the decades and proven. The AR platform needs all the help it to cycle reliably under battlefield conditions. I would not diverge far from the mil-spec design that includes a 2-stage trigger and a 5.56 chamber, and other features found on the variations of the original A1 rifle. See the interview of Eugene Stoner, the designer of the M16 about these and other issues he considered during the design process. Stoner was not educated as an engineer. He was a natural-born engineer who learned the realities of the battlefield as a Marine working in Ordnance during WW2. This is not to say the platform has not been greatly improved since then or perhaps it has not. In this interview is a discussion of the problems and solutions discovered during the development of the M16A1 rifle. It provides unique insights by the inventor himself. See: The Eugene Stoner Tapes – Part 1: Designing the AR-15.
Optional Cartridges for the AR-15 Platform
When it comes to buying a replacement AR barrel, the only other cartridge that could realistically be available in an austere world would probably be 7.62×39. AR-15 magazines might be used to feed no more than 10 rounds of 7.62×39 from a 30-round mag. JWR recently suggested two possible sources of reliable magazines for the 7.62×39 cartridge in the same article where Bull Dog offered sage advice about AR’s here: Building a Versatile AR, by Bulldog
Before buying 7.62×39 magazines for the AR-15 platform, serious research would be needed before making taking the risk of purchasing the upper in 7.62×39. There are several issues with this conversion to consider in addition to the magazines. Bear Creek Arsenal sells an interesting line of AR-type rifles in 7.62×39, perhaps this would be a better option for those who are not fans of the AKM. There is more to be done than simply finding the most reliable magazine for the conversion. One might begin their investigation of the magazines needed to use 7.62×39 in the AR at the AR15.com website: Are the ASC 7.62×39 30 rd mags actually the C Products mags?
.300 Blackout
I would very much like to have an AR-15 in 7.62×39, but I would not only have to buy a complete upper, a suitable buffer, adjust and polish the feed ramps but also take a chance that I could find reliable magazines in the future. If one can afford to diversify then research the several issues thoroughly, or simply buy an AKM clone from PSA. As a better choice for the AR-15 platform would be .300 Blackout. As a reloader with plenty of .308 projectiles on the shelf, it would be fairly easy to reload for .300 Blackout if I had the faster burning powder needed. I do happen to have a pound of the obscure Winchester 296, yet the short list of suitable powders that include the more readily found powders such as H110, and IMR4227 that achieve a useful level of velocity. In the midst of a socioeconomic collapse, it would be hard to find these in quantity, if at all.
Most rifle cartridges can use medium burn rate powders such as IMR4895, but .300 Backout needs a faster powder. From a reloader’s perspective, I see .300 Blackout as a modern and improved version of the .30 U.S. M1 Carbine round that is greatly improved by the use of spire point ammunition instead of the round nose 110-grain projectile used by the M1 Carbine.
They actually use the most of same powders, yet 300 Blackout has an increase in velocity of about 200 to 300 fps over the M1 Carbine and can use Hornady 110 grain V-max projectiles that produce a maximum of 2,300 fps out of 16-inch barrels. A velocity under 2,200 would provide little hydrostatic shock, but the .expanding .30 caliber bullet would do the job better than 5.56 NATO. The .300 Blackout performance falls somewhere in-between the M1 Carbine and 7.62×39 and has the bonus value of having specialty projectiles made for the .300 Blackout that make an AR in .300 Blackout an ideal subsonic platform.
While some, yet not all 5.56NATO mags work most of the time, I would use magazines that were made specifically for .300 Blackout so that I could sleep well. It is a far better choice as a home defense round than 5.56 NATO, and ideal for short-barreled AR pistols. But keep in mind that it is not in the same class as other cartridges used in battle rifles as the ammunition is not yet widely available. It simply does not have a deep supply because it is not and never was a cartridge used by the military. Cartridges that are or have been used in military rifles are the best choices.
Reloaders would easily find suitable projectiles, but the powder needed for .300 Blackout is not easy to find. Cannibalizing M1 Carbine ammunition for the components to make .300 Blackout would be a viable option to consider as the list of powders used by the .30 caliber M1 Carbine is almost identical. The powder charge is on average roughly 4 grains lower. Fortunately, the 110-grain FMJ RN bullet would feed reliably in .300 Blackout actions. No matter how satisfactory we find .300 Blackout, it is not a cartridge that I would invest in unless I had an excess of wealth to dispose of.
6.5 Grendal and 6mm ARC
While 6.5 Grendel packs a bit more punch up close, 6mm ARC would be the better replacement for 5.56NATO as it flies flatter, bucks the wind better, and hits harder at all ranges. In the early years of development of the M16A1, a 6mm cartridge was proposed as a replacement for 5.56 and perhaps the boat was missed at the juncture. Timing can be everything. Had the war Vietnam War not been the making or essentially was in progress as the M16A1 was being adopted in favor of the M14, the M16 could have used a 6mm cartridge. If I were to select a replacement cartridge for the AR-15 platform, 6mm ARC would be the pick.
JWR Adds: The available supply of 6mm ARC is pitifully small, so I cannot recommend it for preppers, except perhaps as a spare upper, for someone wealthy. Adding any oddball cartridge requires an expensive commitment to stocking up on ammunition.
Other Cartridges to Consider
Alas, an ideal cannot be a reality if circumstances negate an otherwise sensible choice and we must go with what we have. Because of the vast quantities of 5.56 ammunition available, 5.56 NATO is the best choice. If another caliber is desired the issue could be resolved by investing instead in a large quantity of 77-grain OTM 5.56 ammunition. Or, if we already have much training on the AR platform we’d rather not compromise, the next and better step would be to add an AR-10 chambered in 7.62mm NATO to the collection. M80 ball is lower in cost and only second in terms of availability to 5.56 and is far more effective than any of the other alternatives available. And we can step up to M118 match ammo for longer distance shots in the wind that is far better than 5.56 NATO 77-grain OTM ammunition. The 7.62 NATO is the most logical choice should we be seeking to diversify and to improve our firepower. The 7.62 NATO would turn cover into concealment and drop attackers with energy three times greater than 5.56 NATO. It is worth its weight in gold if you can handle the added weight. In my opinion, adding just one AR-10 would make an important improvement to a fire team that used primarily 5.56 NATO.
5.56 Replacement Uppers
The example below is not only a replacement barrel, but like an ‘everything bagel’ — a replacement everything that solves many problems, seen and unforeseen. It is a whole replacement upper half without the expense and hassle of getting a complete rifle or a lower group that would require FFL paperwork. If we do not know how to replace parts to fix our AR, then simply pull out the two receiver pins and install this complete upper assembly onto your lower and you almost have a new rifle. If you do not want a 20-inch barrel, then PSA has many other complete uppers for sale. I would avoid the plastic handguards as these can melt if the barrel is allowed to get very hot. I would also gravitate toward a premium barrel from PSA for better accuracy, and a 20-inch barrel that would also improve accuracy at mid-range distances, and extend the practical range from 400 yards onward. A free-floated barrel is better yet, and a smooth and crisp two-stage trigger will improve accuracy perhaps more than would a free-floated barrel. I would not want a target rifle trigger on a battle rifle. When the adrenaline kicks in a light single-stage trigger would too easily be pulled by accident. A heavier 2-stage trigger provides feedback to the shooter and adds a margin of trigger control.
If I could only have one rifle and it had to be an AR-15, then I would want the 20-inch barrel with a 1:7 rifling twist. With a magnified scope on top and 75/77 grain ammunition, it would have a very similar trajectory to 7.62 NATO that could realistically reach out to 600 yards. This upper could replace the need for a scoped bolt action rifle, if if the rifle shoots under 1.5 MOA.
This is a low-budget barrel, but it is a better all-around choice than a more expensive 16-inch barrel in my book:
PSA 20″ Rifle Length 5.56 NATO 1:7 Nitride Freedom Upper – No BCG Or Charging Handle – 516445940, $219.99
(To be continued in Part 5.)
Read the full article here