Reagan was called to active duty in April of 1942, after 5 years of serving as a horse cavalry officer in the Army reserves.
He was in the reserves during that time. He went riding once in a while with them. My son is in the Army National Guard. He has several years of service based on combat deployments, one to Iraq and one to Afghanistan, but I’d hardly pretend he has a also spent the last two years ‘in the Army’.
When Reagan was called to active duty, he did non-riding duty for a month and then transferred to public affairs.