Reflection capture and metal

I am having consistent issues with metallic objects appearing very dark, even with a reflection capture:

Left is Substance and right is UE4.

Is there any setting that could improve this?

There are a number of differences with Painter and Unreal that need to be considered:

Are you using the same HDRI at the same intensity?
Are your Roughness and Metalness maps set to Linear? (uncheck sRGB in the texture properties of the RMA, or the individual textures)
Is your Diffuse value of the metallic area in the correct luminance? Metal reflectance values are pretty bright
What quality setting are you using in Painter? I don’t know which one resembles Unreal the best, but the quality control in Painter can very quickly ruin the reflections, so it’s worth comparing

It’s also worth noting that the two programs don’t use IBL quite the same way, and if you’re using 4.15+, Unreal has a tonemapper that Painter doesn’t support just yet.

Thanks for the explanation, it is quite useful.
The RMA is linear, and we are using the scene capture, not a HDRI.
So I suppose the solution is to tweak the diffuse on the metallic area, and use a custom HDRI.