.204 length?????

It is normal sometimes for an H&R and many other firearms, but not specific to the .204 cartridge itself. Don't let it worry you. Play with your OAL to see if your groups tighten up - maybe they will, maybe they won't - every rifle is different.

There is an enduring myth that production rifles won't shoot at their best accuracy unless the bullet is almost touching the lands, despite the fact that Roy Weatherby disproved it long before many of today's shooters were born. A long leade only kills accuracy if the bullet is not seated concentrically and/or there is insufficient neck tension to hold the bullet properly, and FWIW, those things will kill accuracy regardless of how much leade the chamber has.

While it is certainly true and provable that some rifles do respond very positively to seating way out, many do not. There are no guarantees. Even if there were a "Rule Book", no firearm I have ever met could read it. ;) A long throat (if you take advantage of it) gives you three distinct advantages: use of longer heavier-for-caliber bullets, greater powder capacity, and lower pressure, but there is nothing that says you're necessarily going to see better accuracy because of it. The only way to find out how your rifle will repond is to do some experimenting.

I will generally seat a bullet to the longest possible OAL that will feed and function. That isn't an issue with a single shot, so as long as you have the bullet seated to at least its own diameter into the case neck (i.e. .205" for the cartridge in question) at its max OAL, you have a lot of room to play with to see how it effects velocity and accuracy in your rifle. I have and have had dozens of Contender barrels over the years, and T/C are also commonly chambered with long throats (not all of them - it depends I believe on who made the chambering reamers they happen to be using at any given time - and it's probably the same with many other manufacturers). It's just another variable along with headstamp, powder, bullet, and primer to explore as you work up your loads.

The published suggested Max OAL is there to insure that the cartridge will feed and function in any kind of action: i.e. bolt, semi, pump, etc. With a single shot it's a moot point.