Quote:
Originally Posted by Dean2
A 30-06 Go Gauge measures 2.049 a no go 2.055 and the Field Gauge 2.058. No Go is the preferred head space but is not a SAAMI set measurement and varies by gauge maker. Field Gauge is SAAMI max so .009 head space is the max SAAMI spec, with less than .006 being the preferred head space.
Assuming your measurements are accurate your head space on new brass is .007, have you measured the brass accurately to tell if he brass you are using is SAAMI max, min or in between because you need to know that if you are trying to use brass instead of the proper gauges. Otherwise you really don't know what your real head space is, just what it is for that brass but as long as you keep use that brass it will suffice.
By the way you can order o set of gauges for about $60 and know for sure what your head space is. A .007 head space to the new Norma Brass you are using is generous but does not need to be fixed. What you do need to fix is how you are setting your FL sizing die. Like I said before, you a WAY over sizing your brass and that is why it is separating in two or three firings.
The one thing that makes me suspicious that you may have excessive head space is your comment that the once fired and not resized Norma case has a stretch line in it. As long as it is just a visible stretch mark you are okay, this happens on lots of brass. If you can feel a groove or the beginning of separation on the inside of the case after one firing with factory new brass then you likely have a head space issue.
As much a I understand wanting to learn, trying to do this by typing instructions on a forum is a really hard way to figure things out. This is a fairly complicated issue with a lot of variables that you have not effectively isolated so as much as we are trying to help, a lot of this is shooting in the dark to a large extent. Best of luck.
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Dean, see bolded above. I will check today with the paper clip method or else section the once fired brass with the stretch marks to check it for thinning from the inside.
My next step is to locate a piece of 9mm brass to measure the shoulder position, or else order a no-go gauge.
Edit: I just spent some quality time with a bent paper clip. I first checked the blown out and partially separated Lapua brass to get the feel for the thin section. I then tried on the once fired Norma (not yet resized) and could feel no discernible thinning or circumferential groove on the inside of it. Maybe Dean is right and the external stretch mark on the once fired Norma is not a sign of separation to come.
Another thing I will do is FL resize* some of this once fired Norma and load it up to moderate loads, then shoot it and see what happens.
* FL resize with the die backed out, rather than screwed in further as I have been doing in the past. Once sized (but not yet loaded), I will compare it to my data set using the tape method in chambering. I will aim to have one tape thickness while allowing the bolt to close (indicating approx. 0.0035") and then load and fire. I will then see what happens to the case.
Thx.