Headspace accident question

[Tygrabow]

Just a quick question about the physical risks of shooting with bad headspace...

I always try to get everything right on my guns but I've had people get all excited and tell me that if I repair my own guns, my head would get blown off if my headspace was off a decimal point. Building, rebuilding and fixin' is half the fun for me. I understand the mechanical risks to the gun reasonably well and can imagine how you might get hurt but the hyped up stories seem a bit off.

I'm a private pilot as well and I often study air accident reports to see what went wrong and how I can keep from killing myself in similar fashion so the whole idea of headspace accidents got me curious. I spent several hours online looking for accident reports of people who got hurt due to headspace problems and really didn't find any. I found some where they stuck the wrong cartidge in and things got bad (duh) but, to my surprise, I didn't find a single listing of anyone who really got hurt due to a bad headspace. Maybe I looked in the wrong place, but that surprised me even more cause I know people do crazy stuff.

I'm not interested in the 'knew a guy who heard of a guy who lived next to a guy that did something stupid' stories and really don't want to hear from any well meaning paranoids with no personal experience but if you have personal first hand experience with any headspace accidents I'd like to know the quick and dirty of it... what happened, what weapon, how'd they get hurt and why. Maybe you can help us all.

An old pilot told me once that if I couldn't stand to read the accident reports then stay out of the cockpit. I've learned a lot by reading those and hope to here.

Not being morbid, just trying to learn something.

Thanks in advance.
Jeff

[k98k792]

Well,I was going to post something,but the part about "well meaning paranoids" kinda cut me off at the knees.
Honestly, if you qualify your questions like that,we aren't going to be able to talk much.:wink:

[Tygrabow]

Well not intended to be rough there :-)

My Grandfather was a gunsmith and my Dad did lots of it so I kind of grew up around it. I've done some AK builds and am working a FAL build now. Have fixed and refurbed a few others but I'm no expert by any means.

I have had lots of folks with little or no gun fixin or building experience tell me "you'll blow your head off", "I heard of a guy that did X Y Z", Etc, Etc. I have some family members that I love dearly who have a cautionary tale about everything they never ever tried for why no one should ever try it.

Personally I learn as much as I can and then I try things. A little pain is OK for the experience and I'm happy to learn from folks that either got hurt or were standing next to the guy that did it. The hearsay stories are just that and they get skewed the further they travel so I'm not so interested in those.

I think that sometimes the horse's mouth is the best place to learn from.

-Jeff

[renegade]

Just a quick question about the physical risks of shooting with bad headspace...

I always try to get everything right on my guns but I've had people get all excited and tell me that if I repair my own guns, my head would get blown off if my headspace was off a decimal point. Building, rebuilding and fixin' is half the fun for me. I understand the mechanical risks to the gun reasonably well and can imagine how you might get hurt but the hyped up stories seem a bit off.

I'm a private pilot as well and I often study air accident reports to see what went wrong and how I can keep from killing myself in similar fashion so the whole idea of headspace accidents got me curious. I spent several hours online looking for accident reports of people who got hurt due to headspace problems and really didn't find any. I found some where they stuck the wrong cartidge in and things got bad (duh) but, to my surprise, I didn't find a single listing of anyone who really got hurt due to a bad headspace. Maybe I looked in the wrong place, but that surprised me even more cause I know people do crazy stuff.

I'm not interested in the 'knew a guy who heard of a guy who lived next to a guy that did something stupid' stories and really don't want to hear from any well meaning paranoids with no personal experience but if you have personal first hand experience with any headspace accidents I'd like to know the quick and dirty of it... what happened, what weapon, how'd they get hurt and why. Maybe you can help us all.

An old pilot told me once that if I couldn't stand to read the accident reports then stay out of the cockpit. I've learned a lot by reading those and hope to here.

Not being morbid, just trying to learn something.

Thanks in advance.
Jeff

I understand your question. fact is most of this is 'gray' area, no one wants to be responsible for someone else's mishap, so I think there is an air of 'well meaning paranoia'. Fact is head spacing measurements are there for safety. Having said that, if you yourself elected to shoot a firearm that is out of specification, in that manner, only you would be responsible, if I told you on the other hand, that is was O.K., I could potentially have some liability. Personally, I would not care to stress the limits of the head spacing argument to find out. I think in most cases, common sense should prevail.

[Tygrabow]

I completely understand your answer. I can certainly convince myself to do stupid things but I tend to take the careful approach especially where aircraft and guns are concerned. I probably wouldn't be alive today if I didn't.

The reason you mention though is one of the reasons we all kind of stay in the dark about what the answer REALLY is. Everyone is afraid of liability so no one really gets the straight scoop. We really don't want the safe answer and certainly not the let's be stupid answer. Somewhere in there is the truth.

If I get several people who come forward saying "My smith set my space wrong and I lost a [Substitute body part here]" or "My buddy shot his AK build without checking his headspace and he didn't wake up for a week" then we'll know. If I get a photo posted of a guy with a CETME mag embedded in his foot then that will help too. If no one has a real life direct and personal story of damage then it won't make me take bigger chance but that will tell us something too.

[robocop10mm]

In an HK/CETME the bolt gap is not so much head space as it is an indication of how well the rollers are locking up. If you have insufficient bolt gap, your rollers are not fully locked and the rifle can unlock prematurely leading to problems with blown cases and gasses coming back at you.

Headspace is really a different issue. When headspaced properly, the shoulder (or rim or belt of case mouth depending on what part controlls the headspace) is in firm contact with the corresponding part of the chamber. The head of the case is in firm contact with the bolt face.

When there is too much headspace the shoulder (rim,belt,mouth) are not in good contact with their corresponding parts and the bolt face is not in good contact with the case head. This will cause the case to stretch upon firing to find the headspace point and then send the bullet down range. In an extreme situation the stretching causes excessive bolt face thrust that can and likely will crack or shear off the locking lugs. If cracks start you may not notice them until it is too late and you get a bolt in the eye.

In an extreme situation, the headspace will be so excessive the round will not fire because the firing pin pushes the case forward enough that there is not a sufficinet impact with the primer.

I do not know of anyone who was the victim of such a failure. I think the precautions taken have been pretty good to date. There are many older rifles that are relagated to the "wall hanger" status and will not be shot again.

[renegade]

I completely understand your answer. I can certainly convince myself to do stupid things but I tend to take the careful approach especially where aircraft and guns are concerned. I probably wouldn't be alive today if I didn't.

The reason you mention though is one of the reasons we all kind of stay in the dark about what the answer REALLY is. Everyone is afraid of liability so no one really gets the straight scoop. We really don't want the safe answer and certainly not the let's be stupid answer. Somewhere in there is the truth.

If I get several people who come forward saying "My smith set my space wrong and I lost a [Substitute body part here]" or "My buddy shot his AK build without checking his headspace and he didn't wake up for a week" then we'll know. If I get a photo posted of a guy with a CETME mag embedded in his foot then that will help too. If no one has a real life direct and personal story of damage then it won't make me take bigger chance but that will tell us something too.

Welp, next time me an' k98k792 go shootin' I have him be the combat camera man and give you some real life footage when my mis-headspaced pygmy blow gun backfires and shoots out my posterior we will have some real proof of bad head spacing. Just so we'll be able to show you some results....

Jack Ass has some real good learning videos, maybe, we could get them to try it out, so we have some proof... I learned from them, not to shoot bottle rockets out my ass....:poke:

[Tygrabow]

Good point about the CETME.

[Tygrabow]

Yea I heard those pigmy blow guns were known for headspace issues. Especially the ones that Century made. Oh wait that was the CETME again :-)

[k98k792]

Welp, next time me an' k98k792 go shootin' I have him be the combat camera man and give you some real life footage when my mis-headspaced pygmy blow gun backfires and shoots out my posterior we will have some real proof of bad head spacing. Just so we'll be able to show you some results....

Jack Ass has some real good learning videos, maybe, we could get them to try it out, so we have some proof... I learned from them, not to shoot bottle rockets out my ass....:poke:

Why do I have to hold the camera? :icon_confused:

[renegade]

Why do I have to hold the camera? :icon_confused:

Well, if you really wanna shoot it, I'll take pictures....:drool:

Guess I'm off topic...., I'm gonna go have me some of that 'possum, 'coon, and armydilla Thanksgivin' roadkill medly, I'll observe from a distance.

Good explanation robocop

[turbothis]

i am very much into this headspace idea. what is the accepted amount? what if it was .005" loose? obviously too tight equals not closed all the way but how loose can one go?

[pigpen]

Never heard of any injuries from improper headspace. I have seen some nasty blown out cases from what was attributed to bad headspace. I say attributed b/c I was @ a range 1 time & over heard 2 dudes discussing why the cases were broken. When I asked to look at the case the handed me a handfull of case heads & case bodies. I sugjested they quit shooting the gun, make sure they were useing the right caliber & take it to a gun smith. Never saw them again so I don't know what the problem was. I would guess bad things could eventually happen if you shot a gun like that a lot. I have a few mil surpls, never checked thier headspace & have had only one ruptured case. I attributed that o bad albianian 762x54 ammo. I don't think head space is too much of an issue unless you are changing out parts or building guns. When ever I get a "new" gun I do the old head on one side of a pine tree & the gun on the other test for the 1st shot.

just my 2 penny's

[Malikovski]

I think bad ammo is way yonder more often the cause of a kaboom than anything else.

I've read many tales of things gone wrong. Headspace is sometimes blamed at first, but with further investigation, bad ammo is usually the culprit.

I am anal about headspace on all my rifles, especially those I build, but as far as an actual, rather than potential, cause of catastrophic failure and injury, it's pretty far down the list.

It sounds like the bolt gap is not really a measure of headspace, but rather the health of the locking system.

I don't yet quite understand how the locking system delays the bolt opening but I gather excessive gap leads to poor lock up and therefore premature opening, with similar results to excessive headspace in other rifles.