Head space question

[kc9aop]

Sorry if this is one of those tedious questions I should have found the answer to in th archives.

I bought the L.E. Wilson case gauges and am starting to go through my 5.56 brass.  There are quite a few that the head space is just a touch above the max line.  Is that a big issue?  I know it is out of SAAMI spec but would the difference of the thickness of a 3x5 card be?

Thanks

Jim


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[jepp2]

Will probably depend on your rifle.

I had a die that wouldn't adequately set the shoulder back (unless I ground the shell plate down). They functioned just fine in my bolt gun, but I ended up having problems trying to fire them in my AR. So I have lots of experience with excessive cartridge headspace in my rifles.

In my case, if the case head is only the thickness of a 3X5 card above the max surface of the gage, they would have worked just fine for me. When checking be aware that burrs on the rim can give false indications. I always put them head first into the gage to check for burrs.

BUT the thickness of a 3X5 card on headspace is a huge amount!

Just open your AR upper and slide the bolt back. Drop the sized case in the chamber and see if you can fully close the bolt with finger pressure. If you can they will be fine. If not, they still might work, but no way to know until you try firing them. And the bolt is very difficult to open when it closes part way but not fully. Like I said, I have plenty of practice. I would up resizing everything to end the problem.

 

[Engineer1911]

QUOTE: [There are quite a few that the head space is just a touch above the max line.] QUOTE

Do you mean the case neck sticks out of the case gage too far? If so the case neck is too long.

 

[Rule3]

As Engineer posted above, are you setting the guage with case in it on a smooth level surface? If the case mouth sticks out it is a case length not necessarily a head space issue which would be the shoulder not fitting in the case and the case head not seating on the other end of the case.

Just check the case length with a caliper.

It is when the case head does not seat properly on that end of the gauge that the case (shoulder is not fitting correctly)

Be sure you are using a Sized case. Re check the instructions

 

[SMSgt]

I had a box of .223s I had loaded for my TC Contender before it was stolen. It headspaces differently that most other firearms. I decided to shoot the rounds in my .223 rifle and they were a snug fit when closing the bolt. After resizing normally, they chamber fine.

It does sound as if the OP has a case length problem though.

 

[rwsmith]

Possible stupid question.....

You did trim your cases after resizing? Probably not the problem but it is a variable that could be eliminated.

 

[WR Moore]

I bought the L.E. Wilson case gauges and am starting to go through my 5.56 brass.  There are quite a few that the head space is just a touch above the max line.  Is that a big issue?  Thanks

Jim

You haven't noted if "your brass" was fired exclusively in your rifle or in more than one rifles. No two rifles will have identical chambers/headspace. "Headspace" is properly a condition of the firearm.

OK, let me see if what you write is as follows: the case head of some of your brass extends above the high surface of the base of the gauge. [The narrow, lower level indicates excessive sizing of the brass.] If so, your brass exceeds SAAMI specs for loaded ammunition.

If this is indeed the case and you haven't resized your brass, do so, remove the lube and recheck the brass in the gauge. If the case head is now in between the lower level and top level, your case is properly sized.

If you have resized the brass, the pieces that exceed the gauge length were fired in a chamber that may have excessive headspace. Your sizing die needs to be adjusted to size these pieces down to SAAMI specification. ie, the case head of the sized case should be between the two guage levels.

Now then, if you've just got one 5.56mm rifles, you can adjust your dies to resize the cases sufficiently to chamber easily and not worry about the gauge. That said, it's generally suggested that cases for semi-auto rifles be full length sized back to (actually close to) SAAMI specifications for reliability. Case life may suffer, but reliability is more important.

If you do have concerns about possibly excessive headspace in the rifle, have it gauged by an armorer or gunsmith with appropriate training and gauges. Don't just measure fired cases and make assumptions.