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Posted: 2/14/2005 4:31:43 PM EDT
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Am I right to think that sammi is the most accurate but can only use sporting rounds and NATO is the least accurate but can use all rounds? where the the wylde chamber fit in? |
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.223 us the tightest and is more likely to be accurate if used properly. 5.56 is the "loosest" so that a wide variety of ammo will work in it - military applications. Wylde is something in the middle - can shoot .223 ammo and 5.56 ammo with reasonable accuracy, but tack driving isn't likely, but possible. |
I've never seen body dimensions printed out for each, from what I'm thinking body dimensions are the same. Differences appear though in freebore and leade dimensions. SAAMI is shortest freebore, NATO is longest, Wylde splits the difference. Wylde has shallower leade than SAAMI, not sure about NATO. There may be neck and throat diameter differences as well, just not sure. To say that tack driving accuracy isn't possible with a Wylde I think is wrong. There's lots of competition guns with Wylde chambers that do quite well in SR out to 600. |
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Go here: New Jersey Highpower and look under Reloading Stuph. There you will find the chamber dimensions spelled out. FWIW, RRA and John Holliger at White Oak Precision use the Wylde chamber in all (AFAIK) of their match rifles and those rifles seem to do pretty well. |
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The body dimension is slightly more generouse on the wylde chamber compared to SAAMI .223 chambers, they do this to improve reliability in a auto loading rifle. Bill Wylde designed his chamber to be a match chamber, mine shoots 1/2 to 3/4 groups depending what weight bullet is used as I have to use 3 different loads for accross the course competion. Mongo is not entirely wrong about Wylde accuracy, if you were building a bolt gun tack driver you would not want the Wylde, for best accuracy you would probably use a min. dimenioned .223 SAAMI chamber (although military use, would not due to the ammo they use) to sum it all up, the Wylde chamber is probably the best "match" chamber for an AR-15 type rifle that will use match ammo, having the best compromise between accuracy and reliability and the bonus of being able to shoot SAAMI or Nato. My observations have been with the Wylde chambered barrels the freebore is usurally about .010 less then say what you normally find in an Armalite. You have to be careful not to over do it here as there has to be room for the big 80 and 90 gr. bullets you will have to use in competition yet still have acceptable accuracy from cartridges with lighter bullets seated to magazine length. Again, a compromise. Hope this helps. FA |
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Thanks for chiming in, especially on the body info. I know XTC HP SR has to account for heavy, single loaded rounds loaded around 2.4 and change, yet at the same time time shoot mag length loaded stuff accurately for rapid fire stages. So you're talking around .20 delta between the OALs for each cartridge. I can see how a SAAMI chamber, with a short throat would limit one trying to shoot VLD bullets -- not much boiler left for powder, plus maybe too much neck to the point where the mouth would be beyond the shank and up into the ogive. I know SAAMI chambered varmint rifles, with slower twists, are quite accurate, but those are tailored for 55 grain stuff and under. While maybe more intrinsically accurate, they don't buck wind well enough to use at extended ranges. I guess when evaluating accuracy potential, you need to cap your max range so you know what the requirements are and design around them accordingly. |
No, I was refering to there match barrel . Armalite uses a .223/5.56NATO chamber in all there chrome moly and Chrome lined barrels, these handle SAAMI or 5.56 NATO but they have a 1-9 twist which will not stabilize the big 80's there match stainless steel barrel is a 1-8 twist with a chamber similar to the Wylde, only the lead is different and they have slightly more freebore. For a tactical rifle it should handle all appropriate ammo you would use in a tactical rifle and then some. Condensed to read: Armalites tactical rifles will handle anything you would resonably use in an Tactical rifle, NATO or SAAMI spec. limited only by its 1-9 twist. |
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