AR Sponsor
Posted: 6/22/2017 1:09:56 PM EDT
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I have read a lot of the stickies about building an AR9 but most of it is well dated. So advise me how you would go about this build in today's market. I would like to build or possibly buy new an AR9 for PCC for USPSA. I have nothing to start with as far as magazines or receivers. I would like to stay away from NFA for SBR and cans. I could go with a short barrel and a welded extension to make it legal. I would like to shoot cast bullets of 124 gr. I handload so I have that flexibility to tailor fit the loads to the rifle. I imagine a full length handguard for front hand placement. Of course reliability is an absolute and cost is important. Sights will be some sort of red dot. No lights or lazer. I have no machining capability so it must be compatible as purchased. So:
Decicated lower or AR15 with a spacer? Supplier? Anyone make a full kit that falls into these parameters? What magazines, knowing I need to buy at least 3? Full top Picatanny(sp.) rail or upper only? Gas operated or blowback? TIA |
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Why do you want a short barrel and a welded extension? That adds way too much complexity. Just get a 16" barrel.
My recommendation is a dedicated Glock magazine lower from PSA, and then build your own upper with a Spinta Precision barrel and BCG and whatever free float handguard and upper receiver you like. |
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Agree w/ majorcollins...just buy a longer barrel, screw an extension.
Get on Spinta's e-mail list. They have their bolts, barrels, and other 9mm parts on sale quite often. I just built my 1st 9mm AR and I love it. Ballistics Advantage Barrel Spinta 9mm Bolt Spikes Slick side upper Spikes 9mm dedicated lower ETS glock mags KAK 9mm extended buffer Everything else is just add on's that don't really effect function. Take a look at the 9mm picture thread for build lists and ideas. Lots of good info. |
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Complete Macon Armory upper, with colt pattern. magwell adapter and adjustable heavy extended buffer for $799 shipped. Don't have them up on the website yet but have them on the shelf
Upper features an Aero precision slick side upper with a CMMG 11 inch Keymod freefloat fore arm and out "Guaranteed to Feed black nitride finished barrel. Will run with mag adapter OR Glock lower of your choice and comes with our usual warranty....If something is wrong...we'll fix it.  , and for a limited time we'll be including a metalform mag with the kit.
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decide on which magazine format, Glock or Colt....Colt will have last round bolt hold open ability that works directly off the magazine follower on the bolt hold open lever... Glock will need a linkage... I shoot PCC and have no need for a LRBHO with a 41 round Taylor Freelance extension on my Glock magazine, other than to show clear...
make sure your barrel is throated for 125-147 grain bullets... you will probably want an aftermarket trigger, make sure it is compatible with your bolt, and I think most newer design bolts are... I like the New Frontier Armory modular bolt that uses an AR style extractor, but have a couple of PSA bolts that work fine with pistol size extractors... determine your power factor first, then tune your buffer system... I find my Miculek style comp from McDonald Precision helps control scope movement, others will argue that they don't YMMV... I use a Viet Nam era A1 stock on my PCC as well as my 3 gun rifle as I feel it helps balance my competition rifles.. the rifle length buffer allowed me to experiment with different weight buffers.... I settled on a stock 5.2oz rifle and stock rifle spring with a NFA bumper to limit bolt travel I went with the Glock billet lower from New Frontier because I already shot a Glock pistol format, and find reloading with a short pistol length mag a lot quicker than trying to stick a 32 round Colt stick mag in my SBR... I reload from a standard double pistol mag pouch I like the thin hand guard of the PSA upper I'm using, but did have to throat the barrel... I'm shooting a 146 power factor Bayou 135 with WSF currently using a Vortex SPARC II for optics... Les L747 |
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Here is mine. I use it for PCC Steel Challenge.
I purchased a PSA complete COLT pattern lower. I replaced the trigger with a Timney single stage. I bought a slick side Aero Precision upper. I bought a Kaw Valley 16" thin profile barrel (pretty sure it is made by Faxon). I bought a PSA G-9 Hybrid bolt I bought a Double Star 12.5" free float forend. I bought a Yankee Hill Machine flash hider. Total cost without the C-More red dot was $805.00. It weighs 5 pounds and 11 ounces with the C-More. I did the left side active charging handle modification. 
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COLT pattern vs GLOCK pattern??
Four of us built 9mm carbines this Winter. Two are Colt pattern and two are Glock pattern dedicated lowers. I am convinced the Colt pattern is far more reliable. One Glock pattern shooter has already said he wished he had gone with a Colt pattern lower. The Colt pattern lower has a feed ramp, the Glock does not. The Glock LRBHO is way more complex than the Colt pattern. Jim Skeel |
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Quoted:
I considered the short barrel because of bullet velocities. I understand that a 16" actually slows the bullet down. I wanted a fun gun for local matches. I don't intend to be über competitive. Thanks for all the responses so far. Best of luck with whatever you decide to pursue. MHO, YMMV., etc. |
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the SiG MPX short piston gun is very quick, but can use a trigger... very light recoil... I don't like the ergonomics of the CZ, but that is personal choice... I haven't shot a 9mm Tavor...Beretta CX4 is very reliable... most of the USPSA shooters down here use one of the above or an AR9..some Mech Tech CCUs, Just Right, Marlin Camp etc, but most an AR9.... I would say that those not wanting to experiment with buffers etc go with the JP rifles...there are a lot more options available now, than when I built mine about a half year ago...
at the time I built my original platform, I wasn't sure how much I would enjoy shooting PCC...I don't win many Cadillacs, but still enjoy the sport |
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Quoted:
What are the other options besides the AR9 platform? I didn't see lasnyder mention the MP5/clones or the B&T stuff. I think you could also shoot one of the Uzi variants if you wanted. If you want to go real expensive, you could get a 9mm AUG, Thompson. HK USC/UMP. Again, some options may not be as competitive as others, but they may be as much, or more, fun... Some people decide on budget, looks, or various other factors. Some decide based on what others are shooting. There's a lot of options, but most of the time, it comes down to personal preference. If you aren't sure what you want, you could always find some folks that have the guns you are considering and ask if you can try them. Or, you could find a range that rents and compare some different guns. |
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Quoted:
I considered the short barrel because of bullet velocities. I understand that a 16" actually slows the bullet down. I wanted a fun gun for local matches. I don't intend to be über competitive. Thanks for all the responses so far. It's not correct, but people get confused. Every cartridge has a sweet spot after which more barrel length results in less increase in velocity per inch. For example, in a .223 that is about 18". You still get increases in velocity at 20", 22", 24" and 26", but you just get progressively less increase per inch, and gain isn't enough to always justify the increased length and weight. Below the sweet spot, you start to lose a lot more velocity with each addition inch taken off a barrel. 16" to 14.5" to 10.5" has a profound effect in a .223 and the 6" change from 18" to 12" results in a lot more change in velocity than adding 6" in length length from 18" to 24". This does not however mean that a bullet starts getting slower just because the barrel is past that sweet spot. For example I was working up some loads yesterday in my 9mm AR pistol (10.5") and 9mm 16" AR carbine. One particular 124 gr load had an average velocity of 1,652 fps in my 16" AR carbine and 1,343 fps in my 10.5 AR pistol (although it's actually an 11.125" barrel). That's a 308 fps difference in velocity in a 4.875" longer barrel - an average increased of 63 fps per inch of barrel. This was a load developed with a slower burning powder specifically for the longer barrel. Another 124 gr load, using a typical medium burning powder normally used in 9mm pistols had less dramatic results, but it still showed a signifiant increase: The average velocity of this load was 1,344 fps in the 16" carbine, and 1,246 fps in the 11.125" barrel. That's a difference of "only" 98 fps (an average increase of only 20.3 fps per inch of barrel), but it's still nearly 100 fps and it's most certainly not a decrease in velocity. I've noted that my 147 gr plated bullet loads also gain a fair amount of velocity in the longer barrel. I get 950 fps on average in my 11.125" barrel and 1052 fps on average in my 16" carbine. That's also a solid 100 fps increase in a load using a medium speed pistol powder. About the only place you'll ever see a bullet actually slow down in a barrel is if you are shooting a CB cap - a .22 short round where there is no propellent and the only power for the round is the primer compound. In that case, you'll see a decrease in longer barrels, and in a long target barrel, you might actually get a failure of the bullet to exit the muzzle. ---- The other myth I keep hearing is that a powder that gives you maximum velocity in short barrel is the powder that will give you maximum velocity in a log barrel. I've been hand loading for 40 years and chronographing loads for the last 25 years. That statement just does not hold water when you look at actual data. For example, I hear this a lot in regard to the .357 Mag, but I've got loads of data showing that in a 2.5" .357 Mag I can get higher velocity with a medium speed powder like Unique than I can get with a slow burning colonial ball powder like 296. The difference with a 125 gr bullet is 1300 fps versus 1150 fps, and 1150 fps is only 100 fps faster than I can get with a .38 +P load. Where shooters start thinking the slower powder is faster is in the increased recoil of the slower powder load. It's the difference between launching 9 hrs of Unique and verse launching 20 grains of 296. The gasses and powder residue exit the muzzle about 3 times the muzzle velocity of the bullet and they still have mass. That extra 11 grains of powder mass at 3 times the bullet velocity creates enough recoil to make the slower 1100 fps bullet feel like it has more recoil than the 1300 fps bullet. |
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Quoted:
I have read a lot of the stickies about building an AR9 but most of it is well dated. So advise me how you would go about this build in today's market. I would like to build or possibly buy new an AR9 for PCC for USPSA. I have nothing to start with as far as magazines or receivers. I would like to stay away from NFA for SBR and cans. I could go with a short barrel and a welded extension to make it legal. I would like to shoot cast bullets of 124 gr. I handload so I have that flexibility to tailor fit the loads to the rifle. I imagine a full length handguard for front hand placement. Of course reliability is an absolute and cost is important. Sights will be some sort of red dot. No lights or lazer. I have no machining capability so it must be compatible as purchased. So: Decicated lower or AR15 with a spacer? Supplier? Anyone make a full kit that falls into these parameters? What magazines, knowing I need to buy at least 3? Full top Picatanny(sp.) rail or upper only? Gas operated or blowback? TIA Search....read..... and then buy parts, and then build it. There should be more than enough recent info in build threads, problem-solving threads, etc. to help you build what you want. . |
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