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Posted: 3/9/2010 4:31:28 AM EDT
| I have a NM RRA upper with a Wylde chamber. I have no expierence with this chamber, as I am in the process of a build, and was wondering how well it deals with the 5.56 ammo as opposed to the .223. |
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Quoted: I have a NM RRA upper with a Wylde chamber. I have no expierence with this chamber, as I am in the process of a build, and was wondering how well it deals with the 5.56 ammo as opposed to the .223. I had an RRA w/ Wylde chamber, dealt with 5.56 and .223 w/o any issue... |
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+1 on this, I just signed in to make an almost identical post, lol. The barrel I want to purchase has a Wylde chamber. I was readin a bit about it on Wikipedia, it seems that the chamber was designed to handle the longer 80 gr. bullets. Still confused about it though. What problems, if any, could arise from using this chamber with smaller loads?
Here is the section I found on Wiki... "With the plethora of manufacturers of complete weapons and aftermarket barrels, there is a potential hazard associated with chamber specifications. Both civilian (SAAMI) specification .223 Remington and 5.56 mm NATO are available. Though both chambers typically accept both types of ammunition, the firing of military specification ammunition in civilian specification chambers can produce chamber pressures greater than the barrel is designed to handle. The most common result of firing military 5.56x45mm ammunition in a .223 Remington chamber is that the primer can be forced out of the case by chamber pressure, often resulting in the primer becoming lodged somewhere in the action of the rifle, and disassembly of the rifle is often necessary to remove the jammed primer.[25] Military specification chambers typically have a more open throat area producing less pressure and can handle both types of ammunition. A few AR15 manufacturers incorporate the use of a hybrid chamber specification known as the Wylde chamber. Designed by and named after Bill Wylde, this chambering was designed to accurately shoot the military ball ammo of the day while still feeding reliably. Coincidentally, it shoots the longer 80 gr bullets commonly used in the sport of Highpower Rifle Competition very well and is one of the preferred chambers for that use. While the Wylde chamber allows for optimal seating depth of 80 grain bullets over .223 Remington and 5.56 NATO, it is capable of accepting both ammunition types. The Wylde chamber is used by a few manufacturers who sell "National Match" configuration AR-15 rifle, barrels, and upper receivers." |
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Bill Wylde created the chamber for 5.56mm rounds so you won't have any problems. He designed it to be more accurate when using Canadian 5.56mm IVI C77 ball ammo back when you had to use issued ball ammo for service rifle competitions up here. C77 is made to the same spec as SS109 or M855.
I had to laugh when I read a post about a guy bragging about his new build, he took a barrel with a Wylde chamber and reamed it out to 5.56mm. 
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One thing to be aware of is the difference between the Wylde and 5.56 NATO chamber in the freebore area before the bullet engages the rifling.
The NATO chamber is extremely forgiving. IIRC, it is .2260 - .2265 in this area, and the bullet is nominally .2240. Sort of like throwing a hotdog down a hallway. It keeps the pressures down, but doesn't guide the bullet into the rifling as well, with at least .001 per side between the bullet and the bore. The Wylde chamber is nominally .2245 in the freebore area. That's almost nothing there. A little bit of crud on you bullet or barrel, and it's a slight interference fit. If you have ammo with long bullets like 75, 77 or 80 grain bullets, you'll notice this. Chamber a round by letting the bolt fly. Then extract it by hand. You'll feel some resistance (at least I do, with my RRA / Wilson barrel, with a Wylde chamber). That is because the bullet is sitting in that freebore area if your ammo is loaded to magazine length, and if the bore is a little bit dirty and the bullet isn't perfectly straight and centered in the cartridge case, it's dragging on the walls of the freebore area. If I haven't cleaned by barrel in awhile, it's considerably "sticky" to hand extract. Also, my RRA / Wilson / .223 Wylde barrel will blow primers on hot ammo (with 75 - 77 gr bullets), which won't in a 5.56 NATO chamber. So, what is the "take-away? The NATO chamber is more forgiving of hot ammo and fouling. The Wylde chamber is better for target shooting but is less forgiving. There is no such thing as a free lunch. If you want "match accuracy" and shoot 5.56 NATO ammo, you get the Wylde chamber. If you don't care about "match accuracy", get the 5.56 NATO chamber. |
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Quoted:
One thing to be aware of is the difference between the Wylde and 5.56 NATO chamber in the freebore area before the bullet engages the rifling. The NATO chamber is extremely forgiving. IIRC, it is .2260 - .2265 in this area, and the bullet is nominally .2240. Sort of like throwing a hotdog down a hallway. It keeps the pressures down, but doesn't guide the bullet into the rifling as well, with at least .001 per side between the bullet and the bore. The Wylde chamber is nominally .2245 in the freebore area. That's almost nothing there. A little bit of crud on you bullet or barrel, and it's a slight interference fit. If you have ammo with long bullets like 75, 77 or 80 grain bullets, you'll notice this. Chamber a round by letting the bolt fly. Then extract it by hand. You'll feel some resistance (at least I do, with my RRA / Wilson barrel, with a Wylde chamber). That is because the bullet is sitting in that freebore area if your ammo is loaded to magazine length, and if the bore is a little bit dirty and the bullet isn't perfectly straight and centered in the cartridge case, it's dragging on the walls of the freebore area. If I haven't cleaned by barrel in awhile, it's considerably "sticky" to hand extract. Also, my RRA / Wilson / .223 Wylde barrel will blow primers on hot ammo (with 75 - 77 gr bullets), which won't in a 5.56 NATO chamber. So, what is the "take-away? The NATO chamber is more forgiving of hot ammo and fouling. The Wylde chamber is better for target shooting but is less forgiving. There is no such thing as a free lunch. If you want "match accuracy" and shoot 5.56 NATO ammo, you get the Wylde chamber. If you don't care about "match accuracy", get the 5.56 NATO chamber. Bravo! hoss622 for president! 
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What has become known as the Wylde chamber has a freebore diameter of .2240", if proper. The idea was to seal the magazine length Canadian IVI C-77 bullet and allow bullets yet to come (1984 design) to be seated to the lands.
We had great fun with an early AR (new U.S. specs at the time) service rifle in Canada around 1990. The rifle was shot to 900M in what I suspect was the first scheduled 5.56 competition to that range ever. The little 20" AR came second in the match, but was subsonic beyond 800M. The 28" bolt rifle that was fired alongside the AR remained supersonic. To say that this match at the Canadian Nationals that year (?) was a surprise would be understatement. There was simply not much faith that the 62 grain NATO bullet would make it all the way.:) |
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