So, thinking about reboring a Dakota 76 in 330 Dakota to something a little more mainstream. Wondering what would be the easiest solution without having to get into mag box or feeding issues......
I understand the 330 Dakota is a shortened version of the 404 Jeffrey, so would it work as a 404 Jeffrey?
Other possibilities I would consider: 9.3 X 62, 338 Win Mag

Anything else I am missing?

Thanks for any advice......

Case head diameter!!!!!!!!!!!!!!!!!!!!!!!!!

Over all length

What he said.

If possible i would look at 338 Rem Ultra mag or 338 Norma Mag. 338 Norma mag would probably be my choice if it works in your action as its now a standard cataloged round by our armed forces replacing the Barrett 82 50 cal. It has a future but youll nee to see of you have enough magazine and bolt length

If you do wind up reboring and have some 330 Dakota brass you were willing to part with I would love to pick some up!

In addition to issues involving magazine length and the bolt face/case head there is another problem. The 338 Norma, which someone suggested, is significantly larger in diameter. That results in the barrel shank being too thin especially for a high pressure cartridge.
JRGunmaker is very knowledgeable about Dakota actions. He may know how to reduce the bolt face diameter to accommodate.532 cases.
The RUM cases have a rebated case head so they won’t work.
Sadly, you are in a very difficult spot. Perhaps the easiest is to learn how to form 404 cases into 330 Dakota.

I would look at the 9.3 x 64 as this will take less work than the 9.3 x 62 would, but the bolt face would still need to be welded to the smaller base diameter.. Any of the cases based on the 404 Jeffrey including the parent case would take minimal work except the action will need to be opened up and the bolt stop set back for the full length 404. Any of the short (medium) belted magnums will work but the barrel will need to be set back so much you will have a big gap to deal with, better to get a new barrel. If you have the components already a 9.3 x 330 Dakota would be an interesting one.

One I would consider is a WSM on a fast twist barrel like a 1-7". In 6.5 or 270 this would be sort of like a 6.5 x 284 but pumped up a little bit in velocity. In the 76 action you could seat bullets as far out as they will go with the short case. I would use and shoot this more than a medium bore.

Thanks for all the input guys......what got me thinking about this was seeing a really nice Dakota in 330 Dakota for sale for $3k, which is roughly half of what something like that with lots of options normally goes for. But having talked to a couple gunsmiths about it, including Jess, it seems like it is not worth the trouble.....oh well, it was worth exploring and learned a few things along the way.

330 Dakota is one of the finest cartridges around. Go with it. Believe it or not, 33 Nosler brass is useable in a 330 Dakota chamber.

^^^ NO! Unless you don’t care about extraction.