So a one full rotation in 28" is what he is seeking?
In a side lock (traditional) about your only option is to find a now discontinued Green Mountain LRH barrel for use in a TC Hawken stock or have one made here:
not inexpensive, but I missed getting one of these LRH stainless barrels on ebay years ago and never saw another. I ended up buying a like new used blue one for over $200 and glad to have it.
If this one is still available and someone is serious about getting one this is a chance that won't come along very often.