"It also seems like I read somewhere that the Speer TMJ is a heavy plated bullet." c/o post eleven;

I have shot the Speer TMJ 147gr bullet and don't know if it is a
heavy plated or standard but it is .355" dia. and .643" long.

With a long OAL of 1.165" is does well for light target work from
725fps to a high of 835fps.

The shorter 1.13" OAL by Speer data can reach highs of 971 to 975
with the slower powders that are compressed or close with a ball powder.

This heavy weight is far form making 1200fps but the lighter 135gr might be able to get there in a long barrel........
but I am shooting a 3.5" barrel.

However I see no need for 1200fps in the lighter bullets, even
for just practice loads with a FMJ type bullet.
My max fps acc. load with the 115gr Extreme is 1039fps and the 124 at 1014fps.
As a note, my 125gr coated liked 1015-1046fps for middle of the road accuracy