I have a mid-length Spikes probably that very same one in the picture.
I added magpul parts to it. Shoots great. Here are some other things you
probably don't care about but i'm listing anyhow.
It shoots great with the orginal recoil spring and a much heaver spring.
I've only shot 55 gr federal and yes, some russian junk laying around.
both shot the same accuracy. (4" group using irons at 100 yards)
I haven't put a scope on it yet. so no idea how much better my group
The Spikes lower fits the RRA .458 upper perfectly. No slop, no gaps.
Just in case you want to go with another upper for big game.