Aim ar/m16 6.5 grendel nitride 9310 mpi bdg bolt carrier group $89.95

[montana]

I've studied (and once even witnessed), enough AR Kabooms, to realize the system is quite well engineered. AR Kaboms dont' sent huge fragments into the shooters head (unlike say a 1903 or homemade .50 cal Kaboom!). AR15 Kabooms result in minor scratches, hand brueses, and sometimes skin deep minor bleeding.

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I think differently and would instead cautiously fire the first round from the hip while briefly looking away (obviously pointing in a safe direction). I do that with all new barrels anyway. You can even wear gloves and hold it away from your body if concerned.

The opinions on using head space gauges are rather surprising and entertaining to say the least..

AR Kaboms dont' sent huge fragments into the shooters head
AR15 Kabooms result in minor scratches, hand brueses, and sometimes skin deep minor bleeding..
So yea, checking with gages is great. But don't think it's some insane crazy cavalier risk to take parts
that shoudl be in spec, assemble, and fire


I think differently and would instead cautiously fire the first round from the hip while briefly looking away
(obviously pointing in a safe direction). I do that with all new barrels anyway. You can even wear gloves
and hold it away from your body if concerned.

Too tight a chamber (more common), results in bolt that wont' rotate, and so firing pin that won't reach, and so a "click", and that's it.

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I have three 5.56 barrels that have short chambers that functioned perfectly. Blown primers are the main indication of a short chamber and sometimes over pressure signs on the brass in my experience..
Tight chambers are a completely different problem where the chamber reamer was not properly shaped when chambering the barrel. Brass stuck in the chamber is the main sign of a tight chamber in my experience. A function gauge is the tool used to check for a tight chamber..

[Klem]

The opinions on using head space gauges are rather surprising and entertaining to say the least..

Montana,

What about your bolt guns - Do you buy gauges for all your calibres?

The pierced primers on a short chamber, what happened there? By 'short', do you mean the chamber headspace was shorter than SAAMI's min 1.2201" but still permitted the bolt to rotate into battery and fire?

[montana]

No, I don't check my bolt action rifles that are factory built since they are tested before being sold.. I did learn the differences between throat sizes back in the late 80's when my factory Remington 300 Weatherby blew out the brass on the cases neck from extreme pressure with my custom loads that ran fine in my factory Weatherby rifle. The loads were not anywhere near the high end from my manual but it was my fault for not working my loads up with that particular rifle..Live and learn! Weatherby uses a longer throat than what Remington uses, much like the difference between the NATO 5.56 chambering and the commercial 223, so many disregard as unimportant.. My custom bolt rifles were chambered by my gunsmith using incremental gauges. All three short chambered 5.56 barrels function fine, meaning chambering, firing and extracting without a hitch, yet they won't pass the min 223 go gauge of 1.4636. Two of my AR short chambered 5.56 rifle barrels popped primers out, not pierce them..Pierced primers are usually a sign of excessive firing pin protrusion. One was on a semi auto with a Bushmaster barrel from the early 90's, the second was an Olympic Arms barrel on my class 3 that popped a primmer and lodge in the disconnect channel, which scared the dickens out of my nephew when it ran the full mag after he released the trigger. The third barrel is a 20" stainless fluted Sabor defense barrel that shoots extremely poorly. I blamed the ammunition for a long time for popped primers until I realized the barrels with this problem had short chambers. Amazing what a person can discover with a few gauges and know how. All of my 6.5 Grendel AR rifles are built by me and have passed my go-no go gauges..

[Klem]

No, I don't check my bolt action rifles that are factory built since they are tested before being sold.. I did learn the differences between throat sizes back in the late 80's when my factory Remington 300 Weatherby blew out the brass on the cases neck from extreme pressure with my custom loads that ran fine in my factory Weatherby rifle. The loads were not anywhere near the high end from my manual but it was my fault for not working my loads up with that particular rifle..Live and learn! Weatherby uses a longer throat than what Remington uses, much like the difference between the NATO 5.56 chambering and the commercial 223, so many disregard as unimportant.. My custom bolt rifles were chambered by my gunsmith using incremental gauges. All three short chambered 5.56 barrels function fine, meaning chambering, firing and extracting without a hitch, yet they won't pass the min 223 go gauge of 1.4636. Two of my AR short chambered 5.56 rifle barrels popped primers out, not pierce them..Pierced primers are usually a sign of excessive firing pin protrusion. One was on a semi auto with a Bushmaster barrel from the early 90's, the second was an Olympic Arms barrel on my class 3 that popped a primmer and lodge in the disconnect channel, which scared the dickens out of my nephew when it ran the full mag after he released the trigger. The third barrel is a 20" stainless fluted Sabor defense barrel that shoots extremely poorly. I blamed the ammunition for a long time for popped primers until I realized the barrels with this problem had short chambers. Amazing what a person can discover with a few gauges and know how. All of my 6.5 Grendel AR rifles are built by me and have passed my go-no go gauges..

Montana,

That is interesting. I guess I am still wondering why and how, if the bolt goes fully into battery on a normal cartridge would primers pop out. They obviously can't while in battery so the case must still be pressurized during extraction. Or the pressure was so high that it expanded the primer pocket and the primers fell out on extraction.

I am thinking if your rifles passed a GO Gauge (1.464") then they were all within SAAMI. As we know, SAAMI min for 223 is shorter than a GO Gauge at 1.4636". Your guns were at least .0004" within SAAMI's acceptable range? Maybe it was a tight neck or throat then - preventing proper bullet release and building up pressure like a grenade. Reamers wear in diameter as well as longitudinally and Go Gauges do not check for this.

I have to say that I don't care who chambered my guns or what type they are; every new gun and barrel gets fired from the hip, or from the [concrete] bench with me crouching down below it.

[Old Bob]

I shot 3 gun matches for 20 years. In that time I had only one kaboom it was from faulty, locally re-manufactured 5.56mm NATO ammo using Lake City brass. When the case ruptured it blew a hole out the side of the case just in front of the rim. It also blew the magazine out of the lower & cracked the bolt carrier. The bolt itself appears to be still functional but I retired it anyway. No telling if there are invisible cracks in the lugs. No injuries to me!

I have headspace gauges for all the gas guns I shoot - 6.5 Grendel, 6mm ARC, 7.62X40WT, M1A & M1 Garand. I also have headspace gauges for some of my bolt guns that are used rifles - 8mm Mauser, 7.7 Jap (NO-GO would chamber in this rifle) & 7.62x54R. I use the M1A & M1 Garand gauges with my .308 Win Spanish Mauser (also excessive headspace), Springfield 1903A3 & J.C. Higgins Model 50 30-06 as well.

[montana]

Montana,

That is interesting. I guess I am still wondering why and how, if the bolt goes fully into battery on a normal cartridge would primers pop out. They obviously can't while in battery so the case must still be pressurized during extraction. Or the pressure was so high that it expanded the primer pocket and the primers fell out on extraction.

I am thinking if your rifles passed a GO Gauge (1.464") then they were all within SAAMI. As we know, SAAMI min for 223 is shorter than a GO Gauge at 1.4636". Your guns were at least .0004" within SAAMI's acceptable range? Maybe it was a tight neck or throat then - preventing proper bullet release and building up pressure like a grenade. Reamers wear in diameter as well as longitudinally and Go Gauges do not check for this.

I have to say that I don't care who chambered my guns or what type they are; every new gun and barrel gets fired from the hip, or from the [concrete] bench with me crouching down below it.

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 Wyled 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..

[Klem]

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.

[keystone183]

As for never hearing firing first round from the hip before, you've learned something. I prefer my hips hurt than my face.

I have a tree that i can put arms around that i hold the weapon on the other side of for the first firing. Maybe i should add some gloves to this procedure!

[montana]

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.

I have 4 types of chamber gauges for 5.56, since those are the rifles I work on the most. I have a throat gauge, function gauges, extension head space gauges and normal head space gauges "go, no go and field..I have other function type gauges for AR rifles. Incremental head space gauges are a machining aid and a go and field head space gauges are safety gauges. Knowing if a rifles head space is safe is the first safety check any person can and should do if replacing a barrel, since those gauges are easily available and easy to use. Every bolt should be head spaced to the barrel, this is common knowledge. Faxon manufacturing recommends checking every barrel- bolt head space for function and safety, even their own. Start about 4:30 https://www.youtube.com/watch?v=bRxTQjil4Bc Any firearm could have a defect in metal and become dangerous. Shooting the first round is not necessarily going to be the moment defective metal will fail, so your first looking away waist shooting test is a false sense of security. Excessive or lack of head space will only aggravate any metal defect that may exist. This is why they proof load bolts and barrels.. Checking tolerances is part of the important safety and function testing. We're going to have to trust the manufacturers got the metallurgy right the first time, but this is one of many reasons why I stick with reputable manufacturers.
Alec Baldwin broke one of many safety rules when handling a firearm. He should have taken an NRA safety class instead of trying to destroy them.

[montana]

I have a tree that i can put arms around that i hold the weapon on the other side of for the first firing. Maybe i should add some gloves to this procedure!

Or get a dimwitted buddy to hug the tree.

[keystone183]

Or get a dimwitted buddy to hug the tree.

Maybe i am that buddy...

[Klem]

All those gauges - good luck.

[montana]

Maybe i am that buddy...

Not hijacking this thread, but this reminded me of when my wife and I were competing in a practical shooting competition. I was reloading her mags and noticed some of her friends watching me. I told them I didn't know if these reloads were safe, so I wanted my wife to try them before I did. Not one of them said anything, but they all watched intensely as she shot mag after mag. After my wife finished the course, her friends, "with much relief on their faces" ran up to her and said they thought those rounds were good to go. She had no idea what they were talking about. They told her and my wife looked at me as I was laughing and then commented to me, this is why you have few friends..

[montana]

All those gauges - good luck.

Thanks Klem, but I don't need to rely on luck, I have gauges..