Ive read quite a few places about what they call "headspace" that needs to be set. All I know is it is something to do with the barrel connecting to the receiver. Wtf is this?

AFAIK, this only applies to HK rifles, namely the 20, 30, 50 and 90 series. While the placement of the barrel in relation to the reciever is important (only let an experienced gunsmith remove and reinstall the barrel), headspace is as follows: Its the distance between the bolt head (in battery) and the barrel face. You only have about 1/32 or 1/64 of an inch to play with.
Headspace is important because of the 'roller-lock' mechanism used on these HK rifles (including mp5/94). Too little and you won't be able to pull the bolt back. Too much and the bolt will unlock prematurely during semi-auto fire.

I'm not sure if this applies to any other type of rifle, but for what its worth, thats what "headspace" is. If you want more info, check here: http://www.hkpro.com/Internal.htm

quote:

---

I'm not sure if this applies to any other type of rifle, but for what its worth, thats what "headspace" is

---

I'm certain that applies to any other type of rifle and pistol.

Are you sure? HK weapons have much higher tolerances than most other types. My Mini-14 has a seriously variable amount of space between bolt and barrel. I'd wager that its the same with the M-14, Garand and other rotating bolt rifles.

On the other hand, my HK USC's (an exception to the rule) bolt fits perfectly flush with the barrel face. But its a straight blowback operated rifle.

Pistols, I'm not too sure about.

My $.02

Headspace is the relationship between the breach face and the case neck area of the barrel. If there is too much head space the neck of the case could expand and in extreme cases it could blow up the gun. Too little and the bolt may not close.

site didnt work but I think I get the idea. Tar

che4rev, jogged my memory on this one. Glocks (forty caliber models) were reportively notorius for having a kaboom problem due to a oversized chamber.

I'm pretty sure headspace = over sized or undersized chamber is basically the same thing?

Although are you sure it's not the other way around?

Too much headspace = gun may not cycle properly.

Too little headspace = case might rupture.

I've seen pics of plenty of case ruptures (sometimes blowing apart most of the lower grip frame/internals) and the common theme is the rupture occurs near the rim.

Now it works makes even more sense.

I don't know. Head space on a straight case pistol round refers to the length of the chamber.

Yea, the development Gaston Glock's little plastic gun has been prety comical. Especaily the cops shooting themselves thing. It is like watching monkeys playing with their own shit.

well I read this I might as well let everyone know what headspace is.

headspace is a measurement of the catridge seating in the chamber position right before the bullet is fired the amount of "play" forward or backward when the bolt is closed on a catrige. Target headspace is the point where the bolt face is in a distance with the barell where the bullet is compleatly seated but imposible to shift forward or backwards without adjusting the space between barell and bolt face.

Excessive headspace can lead to everything from misfires to a full-on destroyed reciver (yes it would "blow up" after the trigger was pulled)

Not enough headspace will cause less than total chambering 95% of the time the weapon will not drop the hammer when the chamber is not 100% closed meaning an unfiring gun, however some guns that will fire with a bolt less than 100% closed (such as older guns or any open-bolt gun like an uzi or mac-10)will either destroy the brass or "blow up" upon firing.

weapons to watch headspace in are weapons with non-factory or gunsmith adjusted distance between barell and bolt face. rifles where the barell are screwed on are most common to be requiring to be adjusted properly with a new bolt. AR-15's M-16's bolt action rifles ect.

weapons not typically to be concerned with headspace have universal standard barell space and bolt space, 1911's 92fs' revolvers ect.

headspace is measured in go/no-go plugs shaped like cartriges they are slightly above or below cartrige standards meaning a rifle that holds a "no-go" headspace guage needs to be re-adjusted and NOT fired a rifle that chambers a go guage and not a no-go guage is capable of safely firing ammuntion although there is a broad range of being "ok to shoot" so a properly headspaced gun maybe adjusted even more closley to a specific grade of ammo for the ultimate accuracy the gun can produce although this will limit you to using only a certain grade of ammo in your gun (no more cheap soviet union ammo for your high tolerance chamber)

well I hope I got the point across. questions?

quote:

---

Originally posted by blacksheep18:
... questions?

---

Yes, does it hurt your head holding all that information? (big grin)

Thanks for that clarification. I had a fairly good idea and knew about go/no-go gauges, but you just went about a mile beyond what I even THOUGHT I knew.

Again, thank you,

cc

Ok, I did a little research and this is what I came up with. I hope this wont sound cryptic, but headspace is a given measurement from the face of a bolt, or cartridge shoulder, or cartridge mouth to a given distance in the chamber, or bore of the barrel.It depends on where the manufacturer decides to measure it.It also varies by type of weapon even though it may fire the same cartridge. The bottom line is , if the headspace is too much, you can have ruptered cases or even a catastrophic event (BOOM)!! If headspace is too tight, normaly it wont fully chamber the cartridge.

I was under the impression that the people that shot themselves with glunks were trying to holster or draw their weapons with their fingers on the trigger. Just goes to show ya that Safety Rule No. 2 holds true, especially for cops: Always keep your finger off of the trigger until you're ready to pull it.

lol But thats a little off topic.

Oops, didnt realize that BlackSheep posted the definitive answer while I was typing up a reply. Oh well. Time to pass out. Too much beer for Noah

Noah Out

lol good job, both of you =)