ARP 082 - Keymod Handguards and Accessories

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Welcome to Episode #082 of the AR15 Podcast. I’m your host Reed Snyder and with me today is my co-host, J.W. Ramp.  This is the podcast about your favorite black rifle!  This show is for you; whether you're building your first AR or you’ve been building ARs for years. There is something we can all do to take our black rifle to the next level.

Brownells helps make this show possible.

Don’t forget that Brownells is there for you anytime you make a mistake, like when Jake shoots a takedown pin detent across his avacado green linoleum flooring and it skids under the cabinets.

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Shop for AR-15 parts at Brownells.  Go to: ar15podcast.com/parts

Tip:  Always make sure you read the directions.

Main Topic:  KeyMod History:

Design initiated by VLTOR Noveske collaborated and improved Noveske and VLTOR adopted and implemented Released as an open-source design

Key features and benefits

  • Screws do not separate from the KeyMod nuts
  • design calls for a lug that secures the accessories to handguard
  • drop in install with minimum alignment trouble
  • eliminates abundance of unused rail allowing lower profiles
  • adoption of universal system allows for cross product compatibility
  • low profile of KeyMod nuts inside handguard make it easier to put suppressor inside
  • standardization of processes within the TDP decrease manufacturing costs

Manufacturer’s Noveske - NSR VLTOR - CASV-KM Mega Arms - MKM and MTS Knight’s Armament - URX 4 Geissele - Super Modular Mk4 PWS -  DI Keymod Handguard Midwest Industries - SSK FF BCM - KMR CMMG - RKM

Accessories Picatinny Rail Sections Bipod Mount (PWS or Odin) Hand Stops Vertical Grips Light Mounts (Horntail, etc) Handguard Panels BUIS (KAC) Sling Hooks QD Sling Mounts Barricade Stops Belt Hook

Feedback:

Bob in Keokuk, Iowa:  Reed and Anthony,  On last weeks show a question was asked about the difference between salt bath nitriding and chrome lining. Chrome lining applies a thin layer to the surface of the barrel. The barrel and the rifling would be cut larger depending on the thickness of the coating.

The salt bath penetrates into the steel actually changing the surface of the base metal. Both Nitrogen and carbon are interstitial atoms in the crystal structure of the steel. While elements like Cr, Ni and Mo replace iron atoms in the crystal matrix, smaller elements like carbon and nitrogen sit between the iron atoms. At higher temperatures and high concentrations these interstitial atoms will penetrate into the steel. When they talk about a case depth or thickness in this case it is the depth that the nitriding penetrates into the steel.

By shoving all of these interstitial atoms inside of the crystal structure you greatly reduce the ability for the larger atoms to move around each other. Think of those beaded seat covers. If you have two and you pull one across the other it is bumpy but they will slide. Now take some marbles and shove them in the small spaces in between the beads. Now when you pull them across each other it takes more effort. This is a simplified way to think of how adding these interstitial atoms harden the steel. There is of course a lot more going on there with intermetallic carbide and nitride formation but I think that helps get the idea across.

The advantage I see is that the nitriding does not change the dimensions of the barrel and cannot "flake" off because it is actually part of the barrel. Will the average shooter know the difference I don't know. I went with a stainless barrel for my build. Below is a picture. I had an aimpoint on it at first but Reed says I need to learn to shoot iron sights so by god I am going to learn to shoot with iron sights.

PSA blemished lower. BCM blemished upper. PSA lower parts kit. PSA BCG CAA Interchangeable pistol grip UTG fixed stock. YHM free float hand gaurd Rainier arms .223 wylde, 18", rifle length gas system stainless barrel. Troy industries fixed battle sight YHM folding gas block height front sight.

I have about three hundred rounds through it at this point with one failure to eject. The gun was hot and a steel tula case stuck on me.

Thank you for inspiring me to jump in and build a complete rifle for my first AR. I really enjoy the AR15 podcast an all of the shows on the FRN.

Arturo:   Hi Reed,  How's the weather in Texas today?

Listening to ep #81. Just heard you mention your use of the forward assist. Have an topic idea for a podcast ... proper methods to recover from malfunctions. For example, today I don't think that using the forward assist when the bolt fails to go into battery would be recommend for example. Do you really want to jam a round in chamber if the gun failed to load a round normally? Could cause further trouble depending on the cause for the malfunction in the first place.

Regarding Anthony's problems with steel case ammo. He could try a lighter weight buffer, and/or switch to a low-mass bolt carrier. However, I think his problem maybe that the gas port on his barrel maybe too small for the steel case ammo he's using. Has he tried using different vendors/loads of steel case ammo?

Rob:  Aloha, I know shooting eye dominance is not just for ARs but eye dominance will affect AR shooting. Have you or any of the GREAT GGR shows covered?

How about a back to shooting basics AR show? Safety, proper handling, basic stance etc. If ya think it's boring it means ya need a refresher!!!! Have ya ever gone to a friends house and he wants to show you his new firearm by whipping it out sweeping everyone in the room....luckily the girlfriends/wives have likely wisely fled the room.......and YOU have to ASK him to clear it? Oh, and then he gives you that superior it's not loaded look?

Love da show!!!

DrD:  Here are a couple of links worth reading that pertain specifically to topics you've covered recently and in the past few months.  (I had sent these to Reed, but didn't see them posted and got no response, so I guess he never received them) Enjoy!

Re: MSR Failing episode http://www.defensereview.com/the-big-m4-myth-fouling-caused-by-the-direct-impingement-gas-system-makes-the-m4-unreliable/Re: FN SCAR episode https://www.youtube.com/watch?v=_98MeKrCzwkRe: Barrel episodes (Be sure to read the comments as well as the article.  Many of the responses are quite enlightening) http://www.thetruthaboutguns.com/2013/10/daniel-zimmerman/the-truth-about-barrel-length-muzzle-velocity-and-accuracy/Tim C:  Reed, You talked about steel ammo causing failures in the AR. You might want to take a look at this article: http://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/. This article is pretty exhaustive in analyzing ammo and its affect on the rifle over thousands of rounds. Of particular interest given your show is the lacquer coating you referenced. In reality, the only lacquer-coated ammunition they tested was the Brown Bear. Tula and Wolf have polymer coatings-mainly for the prevention of rust. Also, their conclusion about the lacquer affecting failures was, "We found no evidence to back up the claim that lacquer coatings melt in the chamber and cause extraction failures." In fact, they say earlier that "We shot them until they were too hot to hold – hot enough that a chambered round would cook off in ten to fifteen seconds. We also tried leaving rounds chambered before temperatures reached that point. None of this harsh treatment caused extraction problems." Hopefully this will add to your knowledge base. Love the show!

Mr. King:   Happy Fourth of July, or Independence Day, or... Heck with it. Happy Birthday, America!

On your earlier show #078, you mentioned go/no go gauges. Might I ask you guys what these are, how important they are, and how to use them?

I'll be buying the Magpul adjustable stock and buffer tube next Thursday, and want to stay ahead of the game. I've already bought the vice, punches, hammers and other tools needed -except for the armorer's wrench.

I'm finally all caught up with your shows, and looking forward to the next one. Have a great holiday weekend.

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