Thread: Excessive head spacing 7mm RM - can it still be used

Originally Posted by Vandros

Reloaded about 50 rounds of 7mm RM but bumped the shoulder back 0.02" instead of 0.002" from fire form size (its PPU brass originally from highlands ammo has been fired twice)
At the time I was thinking it was too much and actually dialed it back a bit to 0.015" for most of them

Measured some Highlands & Sako Manufactured ammo and that's even further back at .021" from my fireform size.


Measured a sample of 30 rounds to get the below which is the distance the shoulder has been pushed back from the fire formed size.
Average 0.36mm 0.014"
Max 0.45mm 0.017"
Min 0.23mm 0.009"

Some has been loaded as a ladder so have a range of medium to slightly hot loads.

The question is Will it cause ruptures straight away or have I just taken a few reload cycle off the brass? (cant see that i'll ever load it more than 4 times)

Greetings Vandros,
The problem you are having is well known. Chambers cut for belted cases have often been generous to say the least. As caberslash has mentioned current practice for many is to size the case just enough to set the shoulder back enough to chamber easily. This is done to prevent head separations as early as the third firing if the case is sized all the way back to the belt. This often allows another problem to develop in that the case in the unsized area just ahead of the belt expands an makes the case chamber hard or not at all in some rifles. There is a die available to correct this as caberslash mentions below but a low cost option for the 7mm Rem Mag would be to use a stripped .300 Win Mag FL die body to size that area (take the decapping assembly out first). This may not fully address the tight chambering so a fix I recommended for a friend with .308 Norma Mag cases that would not chamber was to sit the case on top of the shell holder and carefully run it into the die far enough to fix the problem. Next knock the case out with a rod like the one that comes in the Lee Loader kits. It worked a treat for my friend. Only use these steps if you have a chambering problem and only enough to correct it.
As far as pressure goes any change in case volume is miniscule and unlikely to have any measurable efect on pressure or velocity.
To check for thinning of the brass you are looking for a thinning ring inside the case. You can feel for this with a bent bit of thin wire with a sharp point just up from the case head. Easy to detect once you get the hang of it. If you want to section a case to check you need to do it lengthwise and dress it up with a file so you can see things clearly.
Regard Grandpamac.