I have used a pile of Ed Rayl's barrels over the years. I always ordered them with the slow twist and shallow round bottom grooves. Anywhere from .25 cal. to 20 gauge.

Ed will swamp a barrel just how you want it. A nice English barrel just has a whisker of swamp. The Jaeger profile is best fixed by simply sawing off the offending extra, IMHO. Makes for a handy rifle anyway.

My own .50 cal deer rifle has a Rayl 25" barrel with a twist in 95" and .006" round bottom rifling. Although of very light round profile, it's a tackdriver.

I also have a .25 cal squirrel rifle with a twist in 48" and about .005" round bottom rifling Rayl barrel. It shoots #4 buckshot almost touching at 25 yards (plenty good to head shoot a squirrel). Load is 16.5 grains - a K-Hornet cae full - of 3F. Everybody told me I'd never get it reloaded, and you won't if you have .012" rifling and use 4F like all the gun writers. I can load and shoot 20 shots without cleaning, and the last one goes down the barrel just as easily as the first one did. I'm still using the hickory rod made with the rifle almost ten years ago. Just remember to keep any petroleum based oil out of the bore. That little ball only weighs 19 grains, but it will completely penetrate a squirrel's body at 40 yards.

But I have to put my reading glasses on to load it......