Great references for good hunting loads in the 25-5 above, especially the Handloader articles!

One of the main things with a 25-5 is to make sure the bullet fits the throats to maximize accuracy. As most know, some of them had bigger throats. If you have to squeeze a .455+ hardcast bullet down to .451 barrel diameter and you have really close tolerance on the barrel/cylinder gap, I'm not exactly sure if it may present a pressure problem or not. Most of that work is done in the cylinder and, although not exactly a weak point with the 25-5, that's where you gotta be careful. It isn't a Ruger. With a jacketed bullet most of them will be undersized for a big throated gun anyway, so the main consideration is the cylinder strength and as already stated you really want to stay under 23kpsi. Lower is better.

I like the RCBS 45-270-SAA bullet in mine. It shoots quite well. The big Rem .455" swaged 250gr bullets fit the throats better but the long bearing surface of the 270-SAA helps in the accuracy department. It's a good bullet that penetrates well and opens up a big wound channel at moderate velocities.

I like the classic 21.0-22.0 grains of 4227 in mine for a little over 1050 fps (21Kpsi), or even better for me accuracy wise has been 9.5 gr of Power Pistol for just under 1000fps (20kpsi range). The slight difference in velocity between them is probably negligible as far as the bullet performs. Those loads, btw, are discussed in the Handloader #246 that smith crazy referenced that was dedicated specifically to the RCBS 45-270-SAA bullet. They weigh in around 280-282grains. The other reference, Handloader #217 does indeed have one of the best discussions of matching 45 Colt loads and pressures to specific gun types to be found anywhere.

Find what shoots most accurately and you should do OK.

Edit to add: for your original stated bullet choice, a 300gr Hornady XTP, I'm not really sure you could drive it fast enough **safely** in a 25-5 to be pleased with its performance. I would give thought to going the cast bullet route or drop back to a 250 XTP. Of the two, I would prefer the heavier cast bullet driven faster for better penetration than the jacketed one.

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