What are you guys trying to do with low mass solids?
Nothing is a free lunch, chasing all the BC in the world does little if you can't see the information you need.
If your shooting steel at long range let me toss in a few observations, your millage may vary.
Lets make a couple of assumptions:
Assumption A-
Your system is good:
1a.That shooter is solid
2a. The load is nailed with relatively high velocities
3a. Self-spotting is completely wired regardless of bullet projectile weight A or B
Assumption B-
The information from the shot is very important to you:
1b. You would like to see the misses
2b. Frag signature off the plate is an import hit and wind read tool to you
3b. You want to see the watermarks left on the plates
As distances increase, misses, plate movements and impact frag are diminished and harder to see. Mass is your friend when spotting the moment of impact. A 300gr 338 is way easier get feedback from than a 55gr 223, I don't think there would be any argument.
We're are all familiar that on heavy plates at longer ranges that 6mm 105gr bullets can sometimes be a bit harder to spot.. than lets say a 6.5mm 140grain. But solids are WAY HARDER to spot as they do NOT create anywhere near the same frag signature or watermarks as their lead core counterparts. They all share one common issue, caliber to caliber. They have less mass and do NOT frag anywhere close to the same caliber your are shooting.. My 6.5 might frag like a standard 223 on a plate at 500m.
Here are some real examples of frag.. Note that we could see the frag signature in our scopes on both the 285gr and 168gr lead cores, but not the solids even though it was 200y closer.
Here is an example of a 338 285gr lead core 2240. Look at the miss, but really the frag signature coming off the bottom of the plate.
Here is an example at 2200; 200 yards closer than the above sample with a 338 267gr SOLID.. look at how much smaller the watermark is, but really how little and fast the TINY frag clouds is and disappears.
Now back to a 7mm only 168gr 2400y. 200y further than the SOLID example above.. look how much more frag. signature a smaller standard projectile shows than the zippy Solid 338
I've shot more solids that I want, as I live in an area were it is law for hunting.. I also went down the path BC and speed chasing for both long range and ELR. Between those three, I have time on 6/6.5/308/270/7/300/338s. They all share one common issue, caliber to caliber. They have less mass and do NOT frag anywhere close to the same caliber your are shooting.. Solids might be ok .30 cal and up, but a 6.5/6 is really low mass and your really giving up things in Assumption B.
Soooo - if your looking for increase long range performance on steel.. Maybe think of another caliber first.. then when need more but the next caliber's recoil starts to threaten stuff in assumption A, move to solids.