MFH. I'm puzzled. What do you mean by unreliable function? No accuracy. They don't fire? (Probably not that, anyway.)
There was an article a while ago, by one of the writers in either RIFLE or HANDLOADER Magazine. He had a .35 Whelan, improved it, and then went to the Brown-Whelan improved, where the shoulder of the case is blown forward. he said that if he had to do it all over again, that he'd stick with the original Whelan. The amount of gain you would get, using safe reloads, would not be that much, and the Brown-Whelan is a pain in the butt to make. I have a friend who has the B/W and he keeps trying to get me to buy it. I have two .35 Whelans, a custom Mauser and a Ruger 77 MkI. Neither shoot what I call decent groups with factory ammo, but with reloads they are good shooters.
Frankly, I think that Remington dropping the 250 gr. bullet was a mistake. The 200 gr. bullet is too light for heavy game, in my opinion.
Give us more details on what your problem is, and maybe we can figure something out.
Paul B.