montana Wrote:1.4636 is min for the 223, 1.4646 is min for 5.56 NATO. My three short chambered barrels do not meet the basic 223 min, let alone the true 5.56 chamber. I don't have gauges below min and the only other way to know exact chamber sizes would be to make a cast of the chambers. Many chambers marked 5.56 are not true 5.56 chambers in throat length or width. 223 Wylde has a narrower throat than 5.56, yet can have a longer throat dependent on the manufacturer's spec. All three of my barrels have 223 throats. The Olympic has a good 223 throat and proper chamber other than being too short. The Bushmaster has tight spots on the neck, case wall areas and short chamber. The Saber defense has issues in the throat, neck, case wall areas and a short chamber. The Bushmaster would not function at all with steel case ammo.
Out of all the many, many, many people I have shot with through the decades, you are the first person I have heard of who fires the first round from a new factory rifle from the hip or crouching from underneath a concrete bench. How you would manage this with one of my 300 Weatherby's or 338 Win mags would be a sight to see. If I had any concern about a rifle blowing up, I would not be holding it by my hip or at least not without an older steel cup insert for a jock strap. No new plastic type cups would do..
All that is fine, I have the three types of chambers too; 223, Wylde and 5.56. I am still not sure how GO/NO GO gauges would have helped you determine most of those issues before firing. The corollary being, the OP would be in the same situation after buying those gauges. By all means spend money on Grendel gauges but you can get by without them.
As for never hearing firing first round from the hip before, you've learned something. I prefer my hips hurt than my face. The face is where all our major senses are. What would you prefer to lose, your eyes or balls? You can always wear some other sort of PPE and like you say, use a groin protector (thanks for the tip). I have also worn a motor cycle helmet for the first round of a new gun. Hey, if you have one already and it takes only seconds to put it on... Have a good laugh and I'll laugh with you, but - bottom line, Alec Baldwin trusted his armorer and he's not laughing.
Think it through - put a heavy calibre in a rest and sandbag it. Not that I have done this with anything heavier than 303 and 308 but for the sake of a little effort. Using a set of Go/NO Go gauges to predict safety, or trusting the skilled gunsmith is still a risk.
As long as we agree GO/NO GO gauges are a machining aid, and not necessarily a safety aid. You get far more information about the gun by loading a round and firing it safely. The throat, neck or barrel could be dangerously tight yet the chamber passes the gauges. The lugs could be ready to shear on first firing. The barrel extension could also fail. As you discovered, those gauges check only some of what is important and can give a false sense of security.