Recently had a Wyatt's extended magazine box installed in one of my 308s. My goal was to be able to magazine load rounds with the 208 AMax loaded long.

Installation requires opening up the aft end of the magazine mortise in the receiver, and modifying the boltstop for longer bolt travel.

This pic shows before (bottom), and after (top) of the milling typically required in a Rem 700.
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Bolt stop mod,
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I had the install done in Helena at Capital Sports. Price was a reasonable $60 for the labor.

When I got it home I discovered I needed to massage the feed rails just a touch to let them release the longer ammo a bit sooner. Just a couple light swipes with a file and a stone to smooth it up.


The magazine box has internal length of 2.99". I discovered it will also hold two rounds down even loaded at 3.08", and feed fine.

Here are a few more pics.

308 rounds loaded with 208 AMax. OAL 2.81", 2.98", and 3.08". Quickload says useable case volume is 44.7gr, 47.9gr, and 49.7gr, respectively. That's over a 10% increase in useable volume at 3.08".
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Bolt at full rearward travel,
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Four down at 2.98",
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Two down at 3.08"
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