I am considering another 45-70. The choices are either the Marlin guide rifle with the 18 1/2 barrel or there standard rifle with a 22 inch barrel. How much velocity will be lost with the shorter barrel? I do handload.

Right around 75 fps from 22 to 18.5 from what I have seen ofcourse depending on the powder you use.Somewhere it usually averages between 20 and 25 fps per inch of barrel in the .450/45-70.

Good luck...Jayco

Jayco's numbers sound right on. My Guide Gun, Mjolnir, has the now discontinued ported barrel. 405 grain Remington factory loads clock 1200 fps on the nose. The Winchester 300 grain start at 1700 fps. Both factories claim another 100 fps for both from longer tubes. Good hunting!

I didnt know they discontinued the ported barrel. Anyone have any idea why they did?

Too damn loud. Several customers paid us to plug the ports on theirs. I'd rather have the 22 inch one. It is plenty short enough. My measure of a short gun is if I can hold it by the pistol grip and the barrel stays a few inches at least off the ground. I do have a Rem 600 with a 16.1 inch barrel in 358 Winchester. It is shorter than it needs to be and also is damn loud.

snowwolf-Here is some data from Rick Jaimeson first shot out of a 24 inch test barrel and then shot out of the 450 Marlin Guide gun.
Different powders make a difference in velocities.
Speer 400 grain---1987 fps in 24 inch...1811 fps Guide Gun..176 fps diff.
Speer 400 garin---1994 fps in a 24 inch.1856 fps Guide Gun..138 fps diff.

Swift 400 A-Frame..1987 fps in a 24 inch..1856 fps Guide Gun..131 fps diff.
Swift 400 A-Frame..2021 fps in a 24 inch..1928 fps Guide Gun..93 fps diff.

So it ranges from 15.5 fps to 29.3 fps for an inch of barrel.In Garrets loads and there velocities in a 22 inch barrel..They average close to 75 fps less in the Guide Gun or about 18 fps per inch.I always figure about 150 fps from 24 inches to the Guide Gun to be safe or 25 fps but 75 fps from 22- 18.5....

Thats just me....

Good luck...Jayco

I had the long bbl Marlin, my brother has the Guide gun. His rifle shoots even better at 100 yards than my long bbl rifle did. If I was going to get another Marlin 45/70 it would definately be the Guide gun.