I've shot them off-and-on for 35yrs. Me and a friend also use the .257 equivalent (120gr BTHP) in our .25's.
Like Art stated, they're a "little" softer than the equivalent ProHunter (flat-base) and GameKing Pointed SoftPoint BoatTail.
But, from a .30/06, there's little difference at ranges beyond 100yds.
The GREAT THING about these bullets is that they're not deformed by recoil and/or feeding through a magazine like the other two "SOFT!" pointed bullets.
Just day-before-yesterday, I took my Colt Lt-Rifle to the range. I'd left it loaded from when hunting with it back in January (Yeah, yeah, I know- but it was still in the case........nothing in the chamber...) The top round bullet nose was jagged/bent/ mishappend from several trips from the magazine to the chamber. The next three were flattened from recoil of the rifle from shooting the buck I took with it two days before the end of the season. (no, I'd cleaned the gun the evening after shooting it...).
Curious to see what the "damage" to the bullets would do to target impact; after shooting some other ammo I was testing, I went back to the 165's. The mangled nose bullet, landed 1.7" low at 100yds (below zero point), and the 3 flattened nose bullets went into a 1/2" group, 1" below zero. Total group was 1.7", but the first shot "flyer opened the group by over an inch.....
Wouldn't have caused a "miss" on a deer inside 300yds, but a "noticeable" difference in performance.
So, now you know why Sierra finds reason to keep the BTHP "GAMEKING" in the inventory. The slight difference in B.C. is really insignificant and changes with velocity regime that it's operating at. Unless shooting over 500yds with UNDAMAGED BULLET TIPS, it wouldn't make any real difference.
Compared to the other bullet I frequently use, the Remington CorLokt, they definitely out perform the CorLokt at extreame range, which is what they were intended to do, anyhow....
I suggest you enjoy your "find" !