Cabales sells the 209 kit made for the Remington 700 ML. It is far better than the Remington kit.
With that said the hang fire and non fire problem with a Remington 700 ML can be from several things.
(1. The bolt must be taken apart after range session or any time you shoot the rifle as the blow back powder residue will corrode the fireing spring and plunger. that slows down the force when it hits the cap.
I bought this tool at Gander Mountian for $10.00
(2. make sure the #11 nipple is smoth and the caps slide fully on or you can have trouble with it taking a second cock to fire the gun. First trigger pull seats the cap and the second one sets it off.
(3.The factory spring in a Remington 700ML is notoriously weak - especially as it gets older. This is the spring you need to replace the factory spring....
http://www.gunsprings.com/1ndex.html
REMINGTON 700, Muzzle Loader
BLITZSCHNELL Load-rated striker springs
Factory - Reference Only.: 26 Lb.
Ratings available.................: 29 Lb.
Stock No. 66229.....$ 8.29 ea
Hope this helps you out.
By the way I have one in 50 cal and another one in 54 cal. Wouldn't think of owning any thing else except maybe a Savage.

Al