Another chronic issue with shooters:They will take one experience 3 decades ago and hang on to it for eternity.
About 1970 I utterly destroyed an antelope with a 160 gr Sierra boat tail.I had no chrono,but I was putting 70 gr of $1.60 a lb surplus 4831 behind it with a CCI mag primer.
DISCLAIMER!!That was a little over Max back then,and it was a totally different powder than the H4831 of today.That load would be very dangerous with today's H-4831.Don't even think about trying it.
Anyway,it was a zippy load,the bullet blew up,and fortunately the hindquarters were OK.
Silly me,I suspect,because Sierra still is in business,maybe they said "Well,maybe that 7mm design we cooked up for the 7mm Mauser is no longer cutting it with all the 7mm Mags.Perhaps e ought to toughen up those jackets a bit...harden the lead a touch"
Or whatever.
A failure experience decades ago is probably meaningless to a product that is still on the market.Without improvement,it likely would no longer be produced.
If you look to one of the load manuals where J.D.Jones writes the intro to the the 6.5 JDJ handgun cartridge..silhouette/hunting single shot round..he says the typical 6.5 hunting bullet of the day was designed to perform in the 6.5x 54 and 6.5 x55 velocity range.I chose 120 gr 6.5 Ballistic tips to shoot in my MOA in .260 for that reason.
The .264's were relatively specialized and not all that common.IIRC,there was something about a two diameter bore ride factory load bullet they were throated for.
30 yrs ago,the Nosler partition and the Grand Slam were the tougher bullets.They would be a terminal ballistic match.Unfortunately,the BC on them was probably lower than the MK.
But with bullets like the Long Range Accubond,some of the Hornady's,...why apply yesterday's mediocrity in lieu of today's excellence?
Makes no sense.