there are several differant types of James Rifles with 3.8" bore. There may be a variance between them.
The most common rifling was of ten lands and grooves of a right hand twist. what was not known and may be still be unknown is whether the James rifling used uniform twist or used a increasing twist, called a gain twist. This may be why you may have trouble getting a answer to your question. It appears the answer is uncertain.
Ron