save yourself some grief and make a shield to protect your chronograph. A sabot will do havoc to the the chrony particularly out of a savage.
The one the OP illustrated will do nicely.
I made a protective shield out of 5/8" plywood to protect the eyes on my Oehler.

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[Linked Image]
Here's one of the busted sensor protectors. luckily the eye wasn't damaged and is still functional.
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