Whether it be factory or reload ammo, should we not gauge the ammo using a specific chamber cut. Example, we don’t fire 556nato in 223rem chamber, so why would we use 223rem gauge for 556nato ammo? Example-2, if my chambers are all Wylde cut, should I not use a Wylde cut gauge to check ammo?
Gauge is only for me to check headspace for my sizing die setting. Nothing else matters. The ammo gauge can be used to see if a dented round will chamber smoothly. The gauge has nothing to do with throat dimensions.
Since 556 and 223 reamers are many and the sizes vary, datum/headpspace is not the only single item that would make ammo not fit right. 556 case is not the same as a 223 case.
The slotted ammo gauge will allow you to see where the issue might be, which may not be distance to datum on case, that # may be spot on, but something else is off. And since chamber cuts vary, this may the diff between ammo good vs ammo bad.
If my rifle chamber is 556 cut, then I want a 556 ammo gauge. This is why some smiths who ream a chamber, will use same reamer to make ammo gauge, it’s the right way.
Externally, the dimensions of a 5.56 NATO case or a .223 REM are the same. The differences between 5.56 and 223 cases, advertised or discovered, are metallurgy, material thickness and internal dimension resulting in differing case capacities. Sources for this position include Hornady Reloading manual and Starline Brass (Sierra’s sister company). If there are sources out there that indicate a difference between 5.56 case and 223 case externally, please share.
The purpose of a case gage is ensuring the case is in dimension of the specified cartridge, again, external dimensions. Since the external dimensions are the same, a 5.56 case gage is pointless.
The difference in chambers between 5.56 and .223 is not to accommodate different external dimension cartridges but to accommodate a very different pressure. A 223 Wylde sort of splits the difference between the two chambers with the goal of maintaining accuracy with the lower pressure 223 loadings. Noveske Mod0/1 is yet another chambering in the mix.
If you want your brass to fit your chamber, then you’re fire forming and neck sizing in a bolt gun. One does not do this for a semi-auto. I suppose a smith may chamber a barrel and cut a case gage to match for extreme precision pursuits, but I can’t imagine a gunsmith doing this for an AR platform. But if that’s what the customer wants and is willing to pay…
You’ve posted links to the same website that sells barrels in multiple threads over two years. In the technical drawing on that website demonstrating the differences, you’ll note, once again, that the big difference is in the freebore. The differences in the parts of the chamber that touch the brass are measured in 10,000ths of an inch. An actual military 5.56 round fits into that .223 chamber’s dimensions loosely enough that there is more clearance than the difference between the two chamber types. Aaaand, it also fits in both Dillon and Lyman guages that are cut to minimum SAAMI .223 specs.
If it fits in the .223 gauge properly, it is correctly dimensioned for any chamber variant.
I’ve shot 10s of thousands of 5.56 rounds loaded to fit a .223 chamber gauge through 5.56, Noveske Match Mod 0, and .223 Wylde barrels, along with commercial .223, 5.56, and military 5.56 ammo. I have found no need to be concerned about the difference in case dimensions or case gauges.
How do you know your case gauge jives perfectly with your chambers?
Just because your generic gauge says the shoulder (of your resized brass) is where it is ‘supposed’ to be does not necessarily mean that the shoulder in whatever particular firearm chamber falls at that exact same place. You could very well be pushing the shoulder back much farther than needed (and overworking your brass) if you are setting your dies to make your brass fit some random gauge instead of the headspace measurement of your actual chamber that you are loading for.
Want to set up your resize die perfectly for YOUR chamber, this is the way to do it. https://www.amazon.com/RCBS-Precision-Mic/dp/B0767CSDMD There are other old school ways we used back in the 70s but it takes too much typing to explain it.
Correct. It means that it falls within the specified tolerance so it will fit and function safely in any firearm that is also made within the specified tolerance. The idea of making things to standards is only how almost everything in the modern world is made to “jive”.
Also, the only thing you can adjust on your sizing die is the depth, or headspace. I explained earlier that the headspace is measured exactly the same for the both 5.56 and 223REM.