Greybeard Outdoors Forum (GBO) probably has the most info. about the old & new H&R muzzle loaders.
It has a separate muzzle loading section for them:
One poster stated that Hubbard's Outdoor Products makes some parts for them.
Originally Posted by gone-hunting
Just recently purchased a replacement colaspable ram rod from Ben Hubbard at hubbardsoutdoorproducts.com ; this rod is better than the original. He also makes parts for the H&R Muzzleloaders. If you need anything you can look him up or call 205-6965-0444.
In the past, Ben Hubbard has made breech plug conversions and primer adaptors. It might be worth inquiring about with either him or on the Greybeard forum.
Originally Posted by whitetailmaniac Reply #6 on: March 26, 2011, 12:22:33
I got a push in 209 plug from ben last year for my 58 and it works great.
Hubbard's Outdoor Products
7926 Hwy 155
Montevallo, Alabama 35115
205-665-0444 or 1-800-236-7486