338 Lapua alternative?

Yeah fair. That's no bueno.

I just got home and looked, it is .015". I read they were jump sensitive so that's why I went with the that particular 260 I have. Oal was 2.9" with the 121 flatline. My 142 smk's are loaded around 2.81" oal with a .015" jump, depends on the lot number of those
 
I didnt think the 338LM would be a big enough jump to justify the price so I bought a damn 50BMG. My reloading experience is extremely limited, but the guys that reload the 750grn Hornady bullets are consistently sending those to ridiculous distances. IM sure you guys that are in the reloading world can read the Hornady 750 load data and know what it means. (Its obvious I dont reload.) And dont forget about the 416 Barrett.

You'll find reloading for .50BMG quite a bit different than reloading for just about any other caliber.

One thing to note is that the people doing world class accuracy with their .50bmg rifles are shooting custom rifles with barrels specifically setup for the 1 type of bullet they are shooting & tend to have very long barrels.

Some other options would be: .416 Barrett, .408CT and the various .375 cartridges as well, but since you already have a .50 BMG, if you don't mind the recoil & the noise, then you can tune it to be very effective long range.
 
Another issue with the flatlines is that they are not designed to transition from transonic to subsonic. They don't handle the transition as well as jacketed bullets would. Plus the splash/signature is less.

In a .30 cal or lesser caliber, it would be hard to justify using the flatlines.
I'd ask @bohem how the 198s work in a 308...
 
Just acquired a TRG42 338LM, an amazing rifle and caliber to match!
I had the 300 WM vs 338LM argument as the rest, but like the strong impact feedback on the 338LM. 338LM has 2-3x barrel life compared to 300WM, and bullet hold is way more solid on the 338LM as well. But price wise 300WM wins hands down!

Using Lapua Scenar 250 grs bullets, Lapua brass and brand new Vithavuori N565 powder. Best load so far is 87 grains and 850 m/s. Better speed with N570, but accuracy is better with N565. N565 flows way better in powder measure if that is used.