View Full Version : Headspace: How often should you check?

September 26, 2000, 17:45
I have 2 FAL's and a third on lay-a-way.

I would assume that the lightly used DSA Carbine I have is probably in good shape.

The rifle on lay-a-way is probably also in good shape (also reportedly lightly used).

However, the SAR-48 (on loan to my brother) is the one I have the question about. It was used when I got it, but I don't know how often or how many rounds fired.

I don't (yet) have a set of headspace gauges for my rifles, but will eventually get ones in .308 and .223. I assume I need Go and No-go (not necessarily field?) gauges? I seem to remember their being a "down and dirty" way to check the headspace--using tape (what kind?) and Federal(?) Match ammo? Can anyone refresh my memory?

Do I even need Go and No-go gauges, or can I just get by with No-go--assuming the rifle chambers the ammo correctly when I shoot?


September 26, 2000, 19:00
if it closes on one pc of masking tape its a go if it closes on two its a no-go.

VERY rough gauge of headspace-get it checked
by a prof.


September 26, 2000, 19:05
I am 6'5", so I have to check it regularly, especially when I go through doors. If I am wearing boots, I might graze my head on the top of the door frame. This is also important in cars. I don't know how tall you are, but if you think you might hit your head, checking your headspace might be a good idea.

Of course, writing a post like this might lend one to tell me to check the headspace in my posterior...

September 26, 2000, 19:42
Once you set your headspace, I don't think that there is really any need to check it again. You might want to check it after you fire a newly assembled rifle for the first time, but that's the only other time I would bother with it (unless you just want to do it for fun). As for the guages to get, I bought Go and No-Go Forester guages to headspace the STG58 kit I was building. Just for fun, I checked the headspace of my SAR4800. The bolt and carrier assembly closed without any resistance on the Go guage and with just a little resistance on the No-Go guage. This probably means that there is a few thousandths too much headspace. I then put the bolt and carrier assembly from my STG58 kit in the SAR4800. It closed easily on the Go guage, but would only close with a hard push on the No-Go guage. So, it looks like the bolt and carrier assembly from my STG58 kit is a better match to my SAR4800 than the bolt and carrier assembly that came with it. Finally, after building my kit, the bolt will close without resistance on the Go guage and will not close on the No-Go guage. According to Gunplumber, this may be a little tight. I'll fire it with some ammo that I have and if I have any trouble, I may take a little more off of the locking shoulder.

- Bret

Scott Jimenez
September 26, 2000, 21:18
once a rifle is assembled and headspaced properly, it only needs to be periodically checked with the field gauge.

US military does this, i believe, on a quarterly basis with the M16's.

field gauge is the max safe allowable HS. civvie HS gauges are slightly more conservative than mil HS.

HS changes with use. do not think that the rifle will never need to be head spaced again unless you never shoot this rifle ever again.

get a field gauge. use it once a year. unless you shoot it as much as a US military M16, then use it quarterly.

you have been warned. ;-p


September 27, 2000, 06:28
Scott's response sounds pretty good.

Remember, that you cannot check it too much. I always tell people who are assembling AR kits that. The head you save may be your own.


Timber Wolf
September 27, 2000, 07:43
I don't believe I will ever shoot one enough to increase the headspace but it is easy enough to check. Gauges are really nice to have around if you mess with military surplus anyway. I headspaced my first STG tight on the .308 GO, it is really to tight for surplus ammo but it shoots very accurately. By suggestion from several on the board I now do not headspace as tightly. Brownell's has "Match" headspace gauges in .001 increments. I am thinking seriously about getting a 1.632 size to use as my "GO" gauge instead of the usual 1.630.

First rule of gunfighting, "Have a gun!".
Timber Wolf, N.R.A. Endowment Member

Scott Jimenez
September 27, 2000, 08:00
let's look at it this way:

for $20 and the time it took me to write this post, i could have headspaced my FAL with a field gauge.

how will you ever know otherwise? counting cases of ammo that you have run through the gun?

$20 insurance against getting your face ripped off seems like a sweet deal to me.

scott out
PS. i'll preface the above postings about field gauges by saying that the rifle needs to have been properly headspaced at assembly with Go and No-Go gauges. if the source of the rifle is in question and you cannot verify that it has correct HS to start off with, get that done first. then all you will need after that is a Field gauge.

[This message has been edited by Scott Jimenez (edited September 27, 2000).]

September 27, 2000, 22:54
EVERY STEYR import 50:00 that has come through this shop has closed easy on a NOGO. I check any gun I'm processing just for kicks, and this has really got me curios. Just got a 50:64 that also closes on a nogo. Its not a 50:64 anymore. I think I'll call it a 50:69. 14" DSA bbl with long flashider. Kindof cool. Why? Why not! We'll see how it works this weekend.

T. Mark "Gunplumber" Graham
Arizona Response Systems
5501 North 7th Avenue, Phoenix, AZ 85013
623-873-1410 http://www.arizonaresponsesystems.com

September 27, 2000, 23:49
Originally posted by Scott Jimenez:

US military does this, i believe, on a quarterly basis with the M16's.

Quarterly? You mean every 25 years, right... Then again, maybe those armorers actually did do something besides kill brain cells on CLP/LSA fumes.

[This message has been edited by sturmgrenadiere (edited September 28, 2000).]