Marlin 45 Cold Cowboy rifle.

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Joined: 01/10/2011

I developed a load for my Ruger Blackhawk for hunting southern whitetail deer.  A 250 grain XTP bullet, 21 grains of Win 296 powder.  Real stiff load in this pistol.  Will my Marlin 25 Colt Cowboy rifle stand up to this load?

Mak's picture
Joined: 03/01/2011
Marlin '94

The Marlin 1894 action is safe up to 40,000psi, but not any higher.  Factory pressures for the .45 Colt are quite modest at 14,000psi. The short answer to your question is a resounding "maybe". The long answer follows...

Its pretty much impossible to accurately estimate pressure based on handloads for pistol cartridges, because by the time pressure signs move into the red zone, they are screaming hot. Think mini hand grenade, and you are close.

Also, 296/110 can create dangerous pressure spikes if load density is not optimal.

What you can do is find yourself a good manual that lists +P data AND pressure. The Hodgdon annual manual did this for several years, I don't know if they still do. In order for this pressure estimate to be valid with your handloads, you must adhere strictly to brass manufacturer, OAL, Trim length-AFTER sizing, and primer type and brand. Any deviation from these components and specifications will NULLIFY any written pressure estimates.
If you find a pressure tested load that works for you, and it comes in at under 40, 000 psi, you can try it in your Marlin-assuming of course that your gun is in proper operating order.
Keep in mind that a steady diet of high performance loads will wear your gun faster, and more dramatically than use of factory pressure loads.
Hope this helps.