I've loaded the 162 A-Max in the 7x57 with some pretty impressive results. Also the 208 gr ELD-M in the 300 Win Mag. However, they will not work in every rifle/caliber combination.
Being a long bullet (because of the high BC they tend to be longer that similar weight bullets in the same caliber) they need a fairly fast twist rate to stabilize. You did not mention the ROT for your rifle, or the make/model of it either. I use the Berger stability calculator, it seems to be pretty close in my experience. There are others, free, online, pick one.
The second is OAL, the proximity to the lands. In some instances you need to either seat very deeply, or longer than your magazine is designed for. The ELD bullets are of a secant ogive design. There are many articles on this design, but in a nutshell I follow a general rule of thumb, that secant ogive bullets like to be very close to the lands, or more than 0.1" off the lands.
If you seat them close to the lands, you will need to test to find the preferred distance.
If you stay at least 0.1" away, the exact "away" isn't that critical.
Remember this is just a rule of thumb, for cup/core bullets, with secant ogive. Tangent ogive bullets behave differently.
Consider the Weatherby cartridges, long(ish) freebore (leade), high velocity, Hornady bullets (secant ogive), and they were accurate. There is no way that those bullets were even close to the lands. What helps is a pressure, none of the Weatherby calibers were what I'd call low intensity.
And when seating, I don't want any pact of the bullets ogive seated into the neck.
If I don't get the results I expect, I try IMR 4350, if it still isn't good, I try a different bullet.
BTW: The 7mm RM can be somewhat cantankerous to load for, each rifle has it's own personality. Persevere, you'll get there. Personally, when my supply of H870 was gone, so were my 7mm RM rifles. My recipe was pretty simple, a case absolutely full, drop tube full, and any weight bullet, with a F215 primer, done.
I have just started reloading in the past year for my 7mm RM and for my first bullet I settled on Hornady's ELD X 162gn. Now I know I'm still in the learning steps with the whole reloading thing but I am a very meticulous person. I have studied and read lots on the subject and feel that I have a good grasp on the subject. I have been using the OCW method for load work up. I know that my gun as well as myself can shoot sub MOA groups so thats not an issue. I have tried different brass, powders, primers and bullet seating depths but I can not get the elds to consistently group. The only thing that has been constant through the whole testing process has been the eld's. I am going to try some different bullets incase my rifle just doesn't like the eld's. Has anyone ever had this issue with eld x or other bullets.
I am thinking I will try some barnes LRX or TSX or maybe some Accubond long range.
My 7x57 is a Ruger #1, RSI, which I measured @ 1:8.75 twist (*1). Velocity 2500 > 2600 (*2). Barrel is 20", load is 46 gr of 4451, OAL 3.125. I used Speer data.
(*1): Ruger began with a 1:9.5 twist, transitioned to a 1:8.75, and eventually used a 1:8 twist.
(*2): I chronographed this bullet with 46 gr of H4350 Extreme. I'm assuming the velocity with IMR 4451 is comparable.
My 300 is a BSA 1:10 twist, 22" long. It is nearly too slow, still stable at 0 deg C, but not by much. My velocity app 2600. OAL 3.42". A truck gun that still shoots 1 moa. 66 gr of Scotland H4831. A starting load, but near Max pressure signs. I'll not increase it. BSA uses rifling like the Model 1917 Enfield, and mine has a tight bore.
The 7x57 is a single shot, the OAL is not limited, I may be on the lands. Magazine on the BSA is 3.45", bullet is about 100 thou off the lands.
My "Old Road Dog".
