I think most would agree that Beam bourbon isn't really heavy on the barrel, you have to go up to 9 years old - Knob Creek - to get some noticeably assertive barrel influence. Even then Knob Creek isn't a bourbon heavy on tannin and wood sugars, neither is Booker's, or Baker.
Therefore, I'd argue the raw grains tend to show up more in its profile - not a raw taste, I'm talking about the effects on the palate of distilling mostly from non-malted grains.
This is exactly the case with pure pot still Irish, now called single pot still Irish. The majority of the mash is from unmalted grains (barley in that case). And there is likewize no charred barrel to cover over that taste. And both this form of Irish and bourbon are typically sold at 6-8 years aging, a bit higher in some cases.
Scotch malt is 100% barley malt which results in a softer taste to begin with and also, the grains taste often is modified with a peat flavour. Finally, Scotch malt is typically aged rather longer than most bourbon and pot still Irish on the market. Redbreast at 12 and 15 years is the outside limit for pure pot still aging but most comes in from 8-10 years age, this is the range of Green Spot for example, and the pot still elements of regular Jameson and Powers are probably around 6-8 years.
Putting it a different way, I think other bourbons would show a similar connection to pure pot still Irish whiskey but often the barrel effect of U.S. straight whiskey obscures it. But I get an Irish-like connection too with WR, with it's pot still component. It presents assertively the raw grains taste - the triple pot stills do even at 159 - yet at 5-6 years aging the barrel doesn't have time to cover it over and transform it. Or take any young bourbon from HH or Buffalo Trace, say, that doughy oily taste from the grains is similar to good Irish pot still.
Just a theory, but to me it makes sense that Irish methods would inform early American ones. I've read that before Bushmills in Ulster - home of the Scots-Irish who emigrated in significant numbers to parts of Appalachia - used all-malt, it used a typical Ireland mashbill of unmalted grains and barley malt...