Some of the number of times it can be reloaded will depend on how hot it is being loaded,and if your dies are set to match your chamber. The better thew fit,less expansion,more loads.
Just inspect your brass real carefull,as soon as 1 shows any signs of fatigue at all its time to replace the whole bunch. I normally toss mine if they need to be trimmed more than a couple times
If I had a standard chamber, fully sizing my brass and pushing hunting loads (not mild, but not having no pressure signs) I would expect 5-6 loads from a batch of 7mm RM brass.
I would keep my eyes peeled open when inspecting brass after third reload (just in case).
I only neck size my 7 Mag brass so they headspace on the shoulders. Both of them, with quite warm loads will run the brass well over ten loadings with no signs of impending failure. Because these are predominately hunting rigs I put new brass into service for hunting loads after 5 reloads, but I have one batch of 30 that I now use only for target work that has over 15 loads on the same cases, and the load is a FULL charge of 4831 under 162 grain Hornady BT Match hollow points. No failures to date, and I have quite a few batches with from 6 to 12 loads on them and no failures in them either.
In general 300 brass will wear out a 7 Rem barrel before the brass is gone and on a 7 Rum you would only need 150 brass to use up the barrel.
Neck sizing, especially with bushing type neck dies, with the correct bushing, can greatly extend brass life. A tight chamber also helps to minimize working of the brass, but with factory rifles, that is just a matter of luck, as many factory chambers are quite generous.
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7mm brass
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