I think I'd be happy with that grouping.

The Speer 350's have been out maybe 4 (gosh - maybe 10 now?) years, - and they do have a 1/16" thick jacket- I've sectioned some - .063" jacket (below the cannelure) and their site noted minimum MV of 1,900fps.

If yours are older than that, I don't know what they'd be - the only other bullet Speer has had in .457 or .458" is the 400gr.

They do look identical to the current 350 Speer. Id so, they might not expand at all, but perhaps don't need to.

Hornady makes both RN and FN in 350gr. as well as a fairly good 300gr. Barnes makes Old Style in FN and Spitzer, both with .032" jackets. The FP usually runs faster than the 400gr. Speers, also with thinner jackets than their 350gr.