kc9aop Sorry if this is one of those tedious questions I should have found the answer to in the 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?
3X5X what. I will assume we are talking about a card used for keeping recipes. Then there is SAAMI, you have a choice, use the Wilson case gage or use SAAMI.
http://www.saami.org/PubResources/CC_Drawings/Rifle/223 Remington.pdf
It should be obvious a reloader should have one standard, there is no way to make SAAMI, the chamber and the Wilson case gage agree. I am the fan of the standard and the transfer.
Next time I would suggest you check the length of the case from the shoulder/datum to the head of the case in the Wilson case gage. It is very simple to do, just place the new/unfired case into the case gage then determine the position of the case head with the top of the gage. The gage has two flats/steps, one is minimum length/full length sized, the top/upper step is go-gage length. You choose a file card, the thickness of the file card is to be added to the length of the of a go-gage: Problem, no one knows the length of a go-gage from the datum to the go-gage head.
Instead of a index card I use a straight edge, the straight edge was suggested as far back as the early 50s when using the Wilson case gage. With the/a straight edge I use the feeler gage. I place the straight edge over the case head then measure the gap between the straight edge and top step of the gage to determine case head protrusion above the gage. All of this information is like SAAMI, if you did not measure the length of the new/unfired case from the datum to the case head measuring the length of the case after firing is a little less than nice to know.
To make it more clear the Wilson case gage is a comparator, success is determined by the skill of the user. When the case is placed in the Wilson case gage the shoulder of the case is supported by the datum, that makes it fail proof as in ‘cannot miss’. the two steps on the Wilson case gage are measured from the datum in the gage. SAAMI says the length of the chamber from the datum to the bolt face is/or could be 1.463” to 1.473”, they list the length of the case from the shoulder to the head of the case as 1.666” but could include anything down to 1.659 (a –.007”). I make my own gages.
It is not absolutely necessary to use a straight edge, for those that have a flat surface the gage with the protruding case head can be placed on a flat surface with the case head down, the gap between the flat surface and the gage can then still be measured with a feeler gage or as listed in a reloading catalog, a thickness gage.
So without knowing the length of the chamber or the length of the case from the datum/shoulder to the case head the protruding case head above the Wilson case gage is just nice to know. I want to know the effect the chamber had on the case when fired, to accomplish that I must know the length of the case before it was fired, I could fire first then then measure then start sizing by bumping, instead I choose to know the length of the case before firing, the length of the case after firing and the length of the case after sizing.
F. Guffey
