The 788 has rear locking lugs, the 7 has forward locking lugs. The 788 has a detachable magazine, the 7 doesn't. The 788 is a full sized rifle while the 7 is more compact. The 788 is out of production, the 7 isn't.
The 788 also had a very fast lock time which helped it gain a reputation as a good shooter. I had four or five of them. The bolt handle came off a few of them including one of mine.
I had one in 222 that wasa real shooter. Then I got bit by the more money bug and sold it and bought a Sako heavy barrel in 222.
I do wish I had that Rem 788 back
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From the Shoreline of Erie before the Great Black Swamp was drained