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Posted: 9/2/2010 2:17:45 PM EDT
[Last Edit: 9/2/2010 3:00:33 PM EDT by do2mind]
Hey, everybody... after poring over "the data", I have a new understanding of something... and I thought I'd share.

If you were to ask in this forum what is different about the "Wylde" 5.56 chamber from other 5.56/.223 chambers... there are some standard talking points that those in the know pass around.

After looking at the specs... the actual chamber dimensions (compared to other variations of .223 and 5.56)... I understand the concepts and differences much better than from reading "descriptions" (which ARE fairly consistent). And I also have an understanding of different flavors of how one might design a "match" chamber.

You may ask my source... here you go... http://www.ar15barrels.com/data/223-556.pdf

Okay, before you say my interpretation is all wrong, and regurgitate the standard talking points everyone else does... LOOK AT THE ACTUAL SPECS... dimensions... diameters / lengths... and think!

Okay, so here's the skinny... and it's pretty easy to remember!

Length-wise, the Wylde chamber is relatively short through the case body, and therefore tight at the shoulder... and long through the combination of the neck, freebore/leade, and throat. Yes... more room for longer, heavier bullets... longer through this area even than the average of 5.56 (contrary to popular opinion that Wylde is an "intermediate" chamber, it's more accurate to say it's a 5.56 match chamber).

Diameter-wise, the Wylde chamber is relatively tight at the freebore (and by proxy the start of the throat)... and relatively loose through the case body and neck, compared to other 5.56 and .223 chambers.

So as I think about the implications... "a reliable match chamber"... yes, it can fire the long bullets.

As for the reliability and accuracy part... diameter-wise, it is only a "tight" chamber in the freebore and start of the throat (gradually less tight relative to the competition as progressing toward the rifling because of a smaller throat angle than most of the competition", and through the case body and neck, it is actually a looser chamber. As I was trying to think how that one tiny area where the clearances are tight would be enough physical contact of metal to metal to get everything aligned in the right spot (at first glance it seems like the rest of the competition being generally tighter, diameter wise would allow the Wylde to "flop around", comparitively, and be less accurate)... but then I turned the chamber vertically 90 degrees in my mind as if firing toward the floor... if Wylde is one of the tightest chambers at the freebore... that means it's one of the tightest to grip the actual bullet (regardless of being relatively loose everywhere else). Theoretically that doesn't stop the case body from flopping around much because the distance is short and the bullet is tapered... EXCEPT... the shoulder! ln my vertical example, gravity is going to push the shoulder of the cartridge against the shoulder of the chamber... and in this case, the shoulder helps the shell be "self aligning" to get the bullet pointing "straight" down the barrel... and BECAUSE the Wylde is also one of the shortest in chamber body length... that means that the bolt pushes it tighter against the shoulder than the average of the competition... so that creates the same "self-aligning" effect that gravity did in my analogy, and the tight freebore finishes the alignment job.

Quite an interesting design philosophy. I didn't understand how a match chamber works, but Mr. Wylde's version seems effective... so... kudos! It seems especially effective to me because once that explosion goes off I'm guessing the bullet and case get thrown around if they have wiggle room, even if aligned pretty well before... Wylde (and match chambers in general) seem to take that somewhat out of the equation by relatively keeping nice and tight against the shoulder. The design philosphy makes it very important to have a chamber and shell casings with the shoulder, neck, and freebore round, symmetrical, and aligned properly diameter-wise, because for Wylde that's where the magic happens (as opposed to the aligning contact being spread around more evenly through the whole case for non-match chambers). .223 Match uses a slightly different approach... tight at the neck instead of freebore, and four ten-thousandths less tight than Wylde at length to the shoulder... but pretty close to the same concept.

I can think of one other "implication" that seems relevant as a downside... due to being looser than average in the case area (even more than the average of 5.56)... you'll get fewer reloads out of your brass due to the brass having more room to stretch during the shot. And just curious (because I have a Wylde chamber)... does the bullet being pushed tighter into the chamber by the bolt increase the chance of an accidental fire? Gotta be very careful where I point that thing, 'cuz it seems to me like it might a little (and even if not very often, it only takes once). And... whether this setup "works as designed" probably depends on how the manufacturer configures/d the allignment of the bolt to the chamber (as tight as Wylde thought it would be or not).

And as far as my comparisons of 5.56 to Wylde and generalizing that Wylde is looser on average... one of the 5.56 specs is also loose and floppy (all around, even at the freebore/leade, and lengths, too)... Clymer... and since I'm not sure which 5.56 chamber spec is used most often, that might change how the "generalizations" go down if Clymer is the most commonly used 5.56 spec. For those of you with Clymer 5.56 chambers... it probably feeds nice and reliably... but now you know why your accuracy is so-so (and maybe some failures to fire because the primer doesn't get whacked as hard?... the shell has slightly more room to "run away from" the firing pin... but just maybe, depends on sensitivity of the primers).

And I also see that "wildcatters" don't necessarily have to create their own chamber... there are enough fluctuations of a few thousandths here and there between the commercially available chambers that some probably just play with that only on the ammo side by using slightly customized brass sizing dies to fit in their chamber of choice this way, or that way.... just guessing.
Link Posted: 9/2/2010 5:02:59 PM EDT
Thanks for helping me understand my rifle better
Link Posted: 9/3/2010 2:45:35 PM EDT
Originally Posted By do2mind:
Hey, everybody... after poring over "the data", I have a new understanding of something... and I thought I'd share.
...
Length-wise, the Wylde chamber is relatively short through the case body, and therefore tight at the shoulder... and long through the combination of the neck, freebore/leade, and throat. Yes... more room for longer, heavier bullets... longer through this area even than the average of 5.56 (contrary to popular opinion that Wylde is an "intermediate" chamber, it's more accurate to say it's a 5.56 match chamber).
...
As for the reliability and accuracy part... diameter-wise, it is only a "tight" chamber in the freebore and start of the throat (gradually less tight relative to the competition as progressing toward the rifling because of a smaller throat angle than most of the competition", and through the case body and neck, it is actually a looser chamber.
...
And I also see that "wildcatters" don't necessarily have to create their own chamber... there are enough fluctuations of a few thousandths here and there between the commercially available chambers that some probably just play with that only on the ammo side by using slightly customized brass sizing dies to fit in their chamber of choice this way, or that way.... just guessing.


Quite the long first post - welcome. Most of your observations are good, some are not because you are only as good as your source is. Randall's chart is good, but does not list the Throat lengths.

The Throat lengths are
.223___= .103"
Wylde__= .307"
5.56___= .339"
Here you can see where Wylde earns its Intermediate chamber nickname.

The 223 Rem throat angle of 3.10 represents 3 degrees + 6 minutes of angle.
The Wylde throat angle of 1.25 represents 1 degree + 15 minutes of angle.
The 5.56 throat angle of 1.20 represents 1 degree + 12 minutes of angle.
Here again you can see where the Wylde earns another mark toward its Intermediate chamber
nickname - the 5.56 actually has a smaller/less-steep throat angle.

Wildcatters usually work in more than a few thousandths, (usually by the dozen) so new complete chamber reamers are needed.
Link Posted: 9/3/2010 3:32:14 PM EDT
I like visuals with numbers along side...


Link Posted: 9/6/2010 7:25:20 PM EDT
Yeah... based on the throat angle, I guessed the throat lengths were different... just realized I probably could have calculated the lengths with trigonometry... nah, too lazy.

It depends on whose 5.56 reamers are used the most, I suppose... the Wylde throat generalizations ARE true for PTG and JGS... but aren't true for the Compass Lake and Clymer versions of 5.56.
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