I agree, RIPP - 20 bore and .222 would work well.

Jim - while that model 305 looks to be in new condition - that price $2,597.00 is ridiculous.

Dozens of Valmets, CZ584-03's and 305's, at tradeexcanada and all under $500.00.
2.25 pages with 40 per page, so 90 guns, of which about 10 are higher priced drillings, something over $2,000.00.

BRNO 502.1 = 12 x 5.6x52R $395.00
https://www.tradeexcanada.com/content/brno-5021-combination-gun-12ga-over-56x52r