458 Win/Lott - 550 grain North Fork PP's

[Honeybadger1983]

Hey guys, I have been on the forum before. I was forced to get a different email address, and well it's been so long since I've logged in that I can't remember any of my credentials, could not retrieve them, and so here I am with a new account.

Anyhow, I am looking to load up some of North Fork's 550 grain Percussion Points in my 458 Win Mag, and also some for my 458 Lott. The Win Mag is a new manufacture Winchester Model 70 Safari; the Lott is a Ruger #1 Tropical in Stainless with the grey laminate stock that I got new back in like 2006.

That said, I am an experienced reloader but would appreciate any info that anyone has to get me jump started here. Load development with these guys from scratch would be very expensive indeed. I have the Woodleigh reloading manual; it has load data listed for their 550's and I have to imagine that is a good place to start here. Erring on the side of caution of course and slowly working up.

Now I will say that I am a huge fan of the IMR powders, 3031 being my favorite and 4064 being another one of my go-to powders. If anyone can point me in the right direction where 3031 is concerned, I'd be extremely grateful. Thanks in advance to anyone that is willing to help me out with this little project.


James

 

[TennesseeHunter]

Howdy,
I’m not sure I can be much help but hey better than nothing. I think you have the right idea with using load data from the woodleigh manual but starting even lower.

I reload the 550 grain percussion points and the 458 win mag but unfortunately those are separate of each other.

If you’d like I could poke around with the online reloading simulator Gordon’s reloading tool and see what it estimates.
Or better would be I could load a few up and see what the results are. I know I have varget, n133, and aa2460, but I’d have to check the imr powders as I might have used all I had on 45-70.

 

[Honeybadger1983]

Howdy,
I’m not sure I can be much help but hey better than nothing. I think you have the right idea with using load data from the woodleigh manual but starting even lower.

I reload the 550 grain percussion points and the 458 win mag but unfortunately those are separate of each other.

If you’d like I could poke around with the online reloading simulator Gordon’s reloading tool and see what it estimates.
Or better would be I could load a few up and see what the results are. I know I have varget, n133, and aa2460, but I’d have to check the imr powders as I might have used all I had on 45-70.

Sent you a DM

 

[TennesseeHunter]

Now I’ve done some loading of this combo.

458 win mag out of a Winchester model 70 safari

550 grain northfork percussion point loaded to 3.37” and that’s as far as possible. I’d go shorter because if the bullets come out even a little because of powder compression they won’t go in the magazine.

Federal gold medal match large rifle magnum primers in Winchester cases

I was doing a sort of simple ladder test firing one load through the chrono and then adding powder. More data would be better but considering the bullets are 3 ish bucks a piece I wasn’t eager to do three round groups.
All loads were shot at 90-95 degrees temp outside

The first of two powders I tried was varget.
59 grains: 1797 fps, already very slightly compressed
61: 1861
64: 1870
65.5: 1940 fps. Slight pressure. If you look close under the right light there’s an ejector mark. I’ve seen factory ammo be worse. Very compressed. Something like 0.25” of compression. I know people say 458 win mag loads aren’t too compressed if the bullet doesn’t unseat, but I usually don’t do that personally.

Moving on to benchmark, which shows some of the highest velocities in load data and being a high energy and somewhat dense powder seems ideal.

59 grains: 1845
61: 1891
64 grains: 1861 fps. Mildly compressed and no real pressure signs. I would ignore this because the case split near the mouth and not near the base. I had loaded every load on this case up to this point. I blame these mid quality Winchester cases.
65: 1900 fps
67: 1947, mild pressure similar to the varget load I did last
69: 1975 fps. A good bit of compression at this point. Another Case split near the mouth. This time clear over pressure signs. Primer cratering significant and the ejector mark is visible from 10 feet away. I wouldn’t personally load more than 66 grains or so of this.

2000 fps seems optimistic for this combo. Maybe n530 has a chance but I think it’d be a stretch. If it could be loaded to 458 Lott oal then it’d be easy.
I load these bullets to 2500 fps in my 24” 460 weatherby with no concern to pressure but then you only have 2+1 capacity.

 

[Luvthunt]

I use Tac in my Lott. Suggest you call Ramshot for info with the 550.