Having issues with my 338 LM, keyholing when attempting to zero. Enlighten me please

[Uisge]

Did you sort this out yet?

There is no reason factory Hornady 250gr BTHP ammo should be keyholing at 50m. 1-10" or faster is enough twist in the barrel to stabilize it. According to JBM ballistics, the Miller stability factor for this bullet in a 1-10 twist barrel at 2750 fps is 2.1 or in other words, plenty fast enough twist.

Do you have a bore scope or access to one? It's just a guess but you may have been sold a shot out used barrel.

As others have also stated , the problem may also be a damaged crown or misaligned brake.

I’m still working on it, I have been in touch with desert tech and have been following their advice to try and get to the bottom, but I have been awful busy at work and haven’t made it out to try it again. When I get a chance it’s going to a gunsmith, if it’s done for it will get re-barreled. I’ll keep you guys posted. It’s my first magnum and I’m pretty inexperienced so at the very least it will be a good learning opportunity.

 

[Uisge]

If it truly is an A2 barrel, it will be fluted and have a 3 port brake on it from desert tech

I have an srs A2 chassis with the A1 18" barrel (non fluted and 2 port brake from factory)

With 250gr Hornady, S&B and PPU BTHP it puts the rounds pretty much in the same hole at 100yds, so I will say there has to be something wrong with your barrel or rifle

Yes it’s fluted, on the barrel and extension with a 3 port brake. It’s been cerakoted at some point. Here’s a pic of the brake and crown I sent to desert tech. Gonna try it again if I get a chance before I send it out to the pros.