Kart .38 1911 Barrels

I slugged my Kart 1911 .38 spl barrel and was surprised to find it was .3545 across the lands didn't measure the grooves since I don't have the tools to do it.
But I was wondering if all .38 barrels are actually 9mm, my Kart 38 Super barrel is the same diameter.

Economy of scale
..kkm also uses .355 for building a 38spl, 9mm, and 38 super

jglenn21 wrote:Economy of scale
..kkm also uses .355 for building a 38spl, 9mm,  and 38 super

I've been using .358" diameter bullets, soft swaged and hard cast in my .38 Kart barrels with some good and not so good results. The hard cast I have sized to .357 and .358 with no noticeable difference in accuracy but have found that with jacketed bullets the .38 Super prefers 9mm (.355).
Which size works the best in the .38 spl wad guns?