Again, they are the original baptists. Your new school baptists are the ones who chose to take the walk … but since your SBC I will make allowances for your amnesia. We are both still Baptists after all the changes.
No. They split from original Baptists in the early 1800's.
One sect within the original Baptists, influenced by the Presbyterian Church, adopted Calvinism to a greater degree. The original Baptists had a large focus on evangelism. But there became dissenting voices.
Daniel Parker was perhaps the most prominent among the original Baptists. He was a hyper Calvinist and Landmarkist (kinda like J.R. Graves was to the SBC). He developed a view that essentially took man as being divided into two unrelated people groups (the "two seed doctrine"). He was influential in Landmarkism and the Anti-missions movement. He arrived at the latter by taking Calvinism to its natural conclusion (evangelism could only make men God's enemy because they would be witnessing to the reprobate and the elect would be saved regardkess).
So missions was one (probably the primary) reason Primitive Baptists split from the original Baptists.
Primitive Baptists split from original Baptists (they were the sect that left the larger body). They were also known as "hard shell" Baptists by outsiders because of their legalism (they later embraced the name).
Another readon Primitive Baptists split from original Baptists was Bible classes outside of the church service. They did not see this as being prescribed by the Bible (another CoC trait).
Primitive Baptists also rejected what they viewed as "progressive" (music instruments in worship, Bible study groups, fellowship halls, etc.).
Essentially Primitive Baptists were Church of Christ Calvinists who affirmed believers baptism. (Not that they came from the CoC).
If you are interested you can read the original correspondence of the time detailing the issue (the split from original Baptists). They are largely in the archives located in Nashville TN. You can read their own words by their own hand. I did (had to wear gloves....tore one page accidentally but don't tell). A lot of the material has been copied to microfiche as well.