Hmm.  Too many to list, but here is the partial list:

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-UHLEK-, 00_buckshot, 03shooter, 1001001, 1911ar-15, 1911SFOREVER, 1SGA, 1shott, 223-4me, 223DEVIL, 224BOZ, 2nd2none, 308wood, 426maxwedge, 45Boy, 45Cal, 4get_No1, 4gma, 50AE-4-ME, 556ng1, 59bisquik, 5subslr5, 6530, 6string, 762mmMAN, A_Hamilton, a320az, aa777888-2, acftgrunt, afiddler, Aimless, AK_Mike, AKsRule, alaman, AlaskaJohn, Alien, alkoe, Alpine, amp1199, AR-SNIPER-15, AR10TShooter, ar15bubba, AR15fan, AR15KittyKat, AR223, arbob, Arc-Lite, Arch-angel, ARdoug, arizsig, Arlis, ArmaLiteSales, ARniesAR, arowneragain, ARs4EVER, Arvin, az-ar, AZGunnut, badhand1, badlieutenant, badredfish, balistic, ballisticporcupine, BallisticTip, BALLS-172, Bartholomew_Roberts, bblake00, beagler76, Belfry_Express, BenDover, BennyFranklin, BigBaby, Bigcat, bigdar15, bigdb1, BigDozer66, bigscrun, BILLBO, billparadise, bismark77, bjurkovski, BlackAdder, Blackbird_Pilot, BlackDog714, blackhawk-kid-223, Blackjack272, blackplague14, blackrifle51, Blackriflefever, Blue84S10, blueinterceptor, BobB, BobCole, BOBK48, bohr314, Boom_Stick, BowersTactical, BPD, Brad86, BravoCompanyUSA, Brett_Bass, brianksain, BrightFlashlights, bsbg, Bugler, bulldog1967, burbanite, BWhalen, C-4, c-rum, C_Sly, C4iGrant, C5TT, Cableman, cajunboy, CalGat, CAM_PIN, CAMII, Captn_Jerry, CAR-10, carbon15, carbonblack, cat-mechanic, CavVet, ccarmory, Cellblock_CQB, centermass69, CFII, cgj, ch11x, ch2000, Chaingun, chainshaw, Chamois, chiz45, chuckhammer, ChuckyT, cigardad, Cixelsyd, ClarenceDammit, ClayP, cluster, CMMG, Cobb, Cold, ColdSteel223, collin_f, colt_sniper, Conley, Corsair, corwin1968, CQBvoodoo, csr, curt, cyanide, CYBIN, cyoungso, cyrax777, Daewoo_rifles, Dan12, danno-in-michigan, Dave_A, Dave274, davenport, davidp14, davio, ddc, deerman, deimos, demilios4, dghboy315, dhg21, Didneyland, die-tryin, dinkydow, Dirtalert, Diss_ipator, DMDRACER, dmk0210, Dog1, DonS, DoubleFeed, DougR, DOW, DPeacher, Dragracer_Art, Dramborleg, DriftPunch, DRNLS, DRobinson, druncuncas, dtomfrank, EamonnWright, ebgb68, EdAvilaSr, eddailey454, egaletti, Ekie, ElevenHotel, endersgame, Energizer, Engineer, eodtech2000, Epsilon, ericpete0311, EricTheHun, eviljoe, Exmarine, F5, fallingwrench, FALna45, fastang50, fijfi, FishEye, five-five-six, five-star, five2one, fizassist, Flotsam, fml, fredreder, FRIZ, gamachinist, Gander, garandman, garr, Garryowen, GaryM, gaspain, GC456, georgemu1, ghengiskhabb, Ghostchild, GIJoe, glimmerman68, GLOCK-23, glock23carry, glock281, Glock31, Gloftoe, gm5226, GODBLESSTHEUSA, GoGators, GoGo, Goose79, gotm4, gotodengo, Green_Canoe, green18, Greg3, GreyGhost, GreyWolf36, grg503, gribble, GrumpyM4, Gunbert, guncrazy69, GunLvrPHD, Gunplay, Guntoting_Spartan, h8mtv, Halfcocked, Hallmark_Ent, hardcase, HardShell, HBAR16, headspace, heavily_armed, Helldog40, Hessian-1, HFlier, hg112, hielo, HighStrung1, HipFiredGun, HK_DUDE, HKocher, HKPDW, Hobbyshooter, Hokie, Homeboy, hondajohn, Honest_Abe, hoosierhick, hound, huggybro, HunterGren, Hydguy, i-SHOT, iceagent, ICU, id_surf, IDK, IGOTTA71, Imbroglio, innocent_bystander, insane4guns, iNuhBaDNayburhood, IowaSam, ipguy, ipsilateral_7, Ire, iveseenalittleontv, iwantone, IYAOYAS467, J-A-R, J962, Jack_Of_Some_Trades, Jailcop, JAKE-T-SNAKE, jake1978, Janissary7, Janus, Jason280, Javak, Jaybo, JBowles, jd1, JDK, Jeep29, Jetlag, jetlink1, JIMBEAM, jjmcrowell, JJustinS, JLShooter, jnewt, JoeyA, John-NC, john316, JohnDM, johnk, JOHNNY223, JohnnyMcEldoo, jollyrancher, Jon_C_, JoshD, JPayne6128, jrzy, jt325i, JTAC_Supply, jtb33, jteal, JThompson, jtw2, junebug68, K1196A, KA3B, kafesAR, kakuta1832, Kamikazi, Karaya1, Kassnar, kc3, Keith_Tapco, Kenny, Keppyz15, Kharn, kickmyllama, kidlightning, kill9cowboy, Kilo_1_1, kindstranger, kingsra, kingston_fisher, klj451, knightone, Kodiak_10, koz718, krallstar, krinkfreak, ktak56, ktguyot, Kuiper, kuo34, Lab_Rat, LABLOVER, LARRYG, last_mile2002, LastDefender, laynlow40, LCPL556, LE6920, leid, limaxray, lippo, Liveforfunjim, livefree, livefreeordieNH, Lloyd-Jr, Lon_Moer, Lord_Grey_Boots, LordStoner, Lumpy196, m_s, m193, M4, M4-guy, M4Guru, M4it, M4Madness, MADBALL, Mall-Ninja, manny1, mano2, MAP, marauder, Mario_FAMOInc, mark5pt56, markl32, Match223, matthelimech, mattld, MaverickMkii, Max_Mike, mayday, mcgredo, mchasal, MCTS, MDC85, me223, Melvin_Johnson, Merlin, Merlin, MiG-21, mikepenn33, mikr, mildbill39, MillerSHO, mindtrix, Misery, MisterFloppy, MisterSuzuki, mjmensale, mohabie,  Molon, mongo001, Mordak, motopix, Mouseomatic, mPisi, Mr_Fabulous, mr_smashy, mragu, Mrrogers1, mspar, MSTN, mthom50, munkalido, munyguru, mwarnick1, MyWar, N3rday, NAKED-GUNMAN, NAM, NateM4, Neanderthal, Negative20, nethole, NevadaARshooter, New_Pup_101, NewbHunter, NHSBill, nhsport, nick13, Niel, nightstalker, NoPlay, NorCal_LEO, norman74, Not_A_Llama, NZGuns, Offspring, Ohio, Oli, omega-metroid, ONEGOODCOP, oneshot1kill, Operator2, orc4hire, Orygun, Oslow, oufree, ovrtym, padoos, PAEBR332, pale_pony, palmer, Panzerman, panzersergeant, Panzerwolf, paraord16, Pat-fujimoto, Patriot328, Paul, Pave, pazzo, pcurtis, pdm, Peacekeeper3073, PennvilleBill, petvet, phatmax, phobia, pighelmet, PinePig, pissedoff, PJ234, plateshooter, pogo, Polyak, PONCHO69, POODLESHOOTER-IN-AZ, post6440, POWER03, PowerSlave, prone, psychotr, PSYWAR1-0, QCMGR, QP031, QuietShootr, R6721, Radose_NM, Raffica, rainman, RAMBOSKY, rangerfreak, raven, rayra, RBAD, RDF71, Recline, Recruit_Killer, Red-Leg, Red_Beard, redfisher, redleg13a, RenegadeX, rep1969, repub18, Resolved, retread, Rhino_66, Rick36, rickinvegas, ricky101a, Ridge, ridinshotgun, RiffRandall, Riotgun, Rip_Roarin_Wacko, rkbar15, rlp2600, Roadhawk, RobertM, RooK, ROSS4712, rssc, Rusty, S-1, s0ulzer0, salaciouscrumb, Samuel_Hoggson, sanchezero, sarge38624, satcong, sbrown, SC-Texas, ScaryGuy, scottmilk9, SCR1, SDavid, Searcherfortruth, SecantOgive, SgtKiwi, shadowjack1, ShakyJake, Shane333, shane45, Sharkman, sharky30, Shasta_Doug, sherrick13, shilohthehoss, shootnfish, sick, sifu, SigKev, Siglite, Silence214, Simonh, SinistralRifleman, sir_osis_of_thuliver, skeeters65, Skibane, skx762, Slacker, slickbt, slidestop, smokeman, Smudge, sniperx, snojet99, soldier666, Southernred, SP10, spike69, spinaBifida, Spitfire75, SPORTSCAR, squeezecockerp7m8, srt205, ssf467, SSG3K, Stainless, Stasher1, staverironbrand, StealthyBlagga, STEEL1212, SteyrMan, Stickman, Stokes, Stove_Pipe, Strag, Stratohopper, Strazz, Striker, Stryfe, SugarD, sundazes, supanate7, swampertwo, Swordslinger, Sydwaiz, Tactical_Jew, TacticalMan, tactmaster, tat2ed-AR, Taxman, tc6969, Teltec01, tequilabob, TexasEd, TexasRooter, tfod, TGorsk08, the, The_Alchemist, The_Bricklayer, the_reject, thebeekeeper1, thebrain, thedr13, thedude73, Thekatar, TheKill, TheKnack, thelastgunslinger, TheLaw, themadhatter, THEMURPH, TheOtherDave, TheRealSundance, TheRedHorseman, TheRicker, TheTacticalSolution, Thunderbolt, Timanator, Titan762, tjmz, Tom87, TomH, TomJefferson, tomtool, tony_k, tonymel19, trashiestzero, TravisAasen, trippletap, Triumph955i, Troy, tspike, TUMOR, Turbozag, tvone, TxLewis, tyranid, unixcock, ursus, user426, USMC_monty, USNvet, USPC40, UTPABRONCS, uxb, V-Rod, Valkyrie, vandal, vedubin01, ViseGrip, vito113, VonOnken, W-W, Walt2, wanabe, wanashoot, wapiti_stalker, warguns, warlord, Watch-Six, WaWaTuSi, WdpIan, weemer, wes1, whisper300, Wingman26, wolffie, Wolfpack, Wombat, wyv3rn, xcpd69, xsiv4ce, Yojimbo, Yute, Z2898, zepp, Zhukov, Zmeja, zoom, zro260n2wks, zyx5432 ...

Quoted: I think you're all dumb for not catching the improper use of the English language: "Who is the dumbest person on AR15.com?" It's "most dumb" not "dumbest" Hokie the Grammar Nazi

 Blame sgtar15.  He started it.