I have done this with a Rem 700 stainless SA with very satisfactory results. I opened up the rear of the ejection port, lengthening the port, until I could eject
300 Win Mag brass. I put a slight bevel on the inside of the front of the port to allow a little extra clearance as the empty case rotated out on ejection. I installed a Davidson style bolt stop as far back on the left rear action as bolt travel would allow. This gun was a 1000 yard Light Class rifle that was a solid 1/2 moa shooter with Sierra SMKs, and but for the sudden disappearance of my spotter during the last minute of the sighting period when I needed eyes on a scope for a wind change, would have likely taken the Score Trophy at the Nationals Match I was compering in. As it was, the final group was 4.5", but 4 " below the sighting card, and I lost Taking the Group Size Award for the relay to a 4" group, and was 5 points below the highest score. My spotter's excuse was "i thought you were good to go, man." I just turned and walked away.
Short answer: yes, it can be done, and with hand tools and patience. Diamond Grinders in a Dremel and good files, and itlooks like it came from the factory that way. Hope this novel answers your question ; )
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