450 Marlin loads with 400gr projectiles

Might just as well go for a 458 Win Mag or Lott as to build a 450M from scratch.

Case dimensions for 450M and 458 WM are really close, except obviously length. The limiting factor on 450M is going to be case length/capacity. And unless you're going to Africa after DG, even the 45-70 loaded up with some Beartooth Piledriver 525 gr or PD junior 425 gr at 1600-1700 fps will easily dispatch anything in North America. Getting to 1900 fps with something like a 525 doesn't improve ballistics significantly over 1625 or so, and it certainly doesn't improve lethality on the thin-skinned game we have here.

Plus, since Marlington doesn't make the 450M anymore, and they never sold a bunch of them, brass will be a lot harder to come by than either of the magnum 458s.

450M is a fine cartridge for what it was designed for, but it sure seems like you're trying to make a silk purse out of a sow's ear.
 
This is from Hodgdon's website:

upload_2018-12-5_7-55-35.png
 
I have a ruger 77 custom in 450 Marlin. Since it is on a bolt action and I don't have to worry about a levergun pressure requirements I started with the max loads on the Hogdon web site and worked slowly up. You can also look at 458 American loads. The 458 Armeican is a 2 in case if my memory serves me and the 450 marlin is 2.1 in. They have about the same case capacity. I will have to look at my notes for the loads I found that gave best accuracy and what the speed was with them.

It is a fun short action thumper. I say if it floats your boat go for it. I enjoy mine
 
I have a Savage 110 off with the smith getting converted to 450 Marlin. In my view a great cartridge only limited by the original platform. Should always have been marketed as a bolt gun round. Not an African cartridge, but plenty of power without being excessive, for general hunting. Also has great potential as a subsonic round if you're in a jurisdiction where that's applicable.

Many older reloading manuals had data for the round, although that data was designed for the limited strength of the lever actions.

Going forward, brass may be a problem. Bertram still make 450 Marlin brass. Hornady appear to have discontinued it, although it's possible they may run limited batches. Maybe if we all send them emails every so often it might increase the chances of batches being run.
 

Forum statistics

Threads
61,342
Messages
1,342,429
Members
115,417
Latest member
RosalineWi
 

 

 

Latest profile posts

Franco wrote on rnovi's profile.
Here's the target for the NorthForks - 25yds off a bag, iron sights. Hunting leopards over dogs the range won't be more than that.

Flew in an airshow in Smyrna years ago, beautiful country.

Best regards,

Franco

IMG_1476.jpeg
Sighting in rifles before the hunt commences.
WhatsApp Image 2025-06-03 at 10.13.28.jpeg
patr wrote on M. Horst's profile.
Thanks for the awesome post my friend - much appreciated, when you coming back with Tiff.
NIGHTHAWK wrote on NZ Jack's profile.
Introduce yourself Buddy…
 
Top