Home Forums Hunting & Shooting Cowboy Action Shooting .45 Colt loads for Marlin

I have somewhat of a problem with light loads in my .45 Colt Marlin Cowboy rifle. I get gas blowing back into my face a good bit. I have used 6 grains of Trail Boss with 200 grain bullets and 5 grains of TB with 250 grain bullets. Those are about 1/2 grain off maximum loads. They shoot well, but I get blowback and the cases come out black and sooty. I have also used 8 grains of Unique behind a 255 grain bullet and have not had any blowback. The load with Unique , however, has a little more power than I would like for Cowboy shooting. What loads do you folks use in your .45 Colt rifles? Have you ever experienced blowback with your rifle? Is it possible that my Marlin has an oversize chamber? I generally use Starline brass but also have Remington and Winchester cases. Any suggestions are appreciated.

Try not resizing the cases.
.45 colt is well known for blowing back, a friend of mine has partially solved the problem in his rifle by not resizing the cases and simply crimping the bullet in tight. He said after three or four firings the cases are well stretched and the bullets just about drop into place but it blows back way less.

I used 6.0 grains of Red Dot with the RCBS 255 SWC and store bought 250 RNFP and had smoke curling up from the back of the bolt. As you noticed, I found that 8 grains of Unigue expanded the cases enough to seal off the gases. The cases I used were Remington. I will probably try upping the Red Dot charge a half grain to see what happens.

The Hodgdon website lists 6.5 of Trail Boss with the 200 and 5.8 with the 250 so you may want to bump up your loads a bit.

I use an RCBS steel die which probably sizes a bit less than the carbides. And I shoot my loads in a New Vaquero so I don't want my cases too chubby.

Since I'm not shooting a Marlin in .45 Colt, I may not be much help, but a couple of ideas come to mind. First, I figure that the SASS guns are HUGE fun, but only when loaded as they were intended. . . .which means that the noise, recoil and power are matching the blackpowder loads, or coming pretty close. This is not the fastest way to shoot, but I enjoy it the most.

Sooty cases usually suggest that a chosen load is not expanding the brass enough to make it fill the chamber, which could also be causing the blowback you mentioned. The load should be double-checked with the manual and see if you can safely increase the powder a bit. Trail Boss is good, but not for everything.

I have gotten some of my loads from an excellent reference book, Action Shooting Cowboy Style by John Taffin. He specifically tested the 1894 Marlin Cowboy .45 Colt using VV-N-100, Red Dot, Tite Group, WW-231 and Unique; bullet was the Bull-X 250. His accuracy was not very good, IMHO. Anyway, it is out there.

Other loads were developed from friends' recommendations or from specific manuals, but I have gone down in bullet weights and been very pleased with the results. I am shooting my Rossi replica M-1892 .45 Colt with two loads, both using 200 gr RNFP bullets.
My everyday load runs 1088 fps (at 10') with 6.3/TiteGroup/200 RNFP using CCI 300 LP primers, in WW brass seated with a firm crimp at 1.585" COAL, which also works nicely in my replica '73 Colt revolver.

My accuracy load is 10.1/VV-N330/200 RNFP using Winchester cases, crimped at 1.582", CCI 300s again. I got @ 1315 fps on the chrono with this one, plenty powerful, with one-hole grouping off the bench. I was bowled over at the accuracy potential of the .45 Colt using this recipe, YMMY.

Please work up to this last loading in your gun and be safe.