I've begun to wonder about the pressure spike created in my loading for an original 1873 Winchester .38-40--DOM 1885.

I know many of you stand by the idea that no old rifle such as this should be loaded with smokeless powder. I acknowledge your stance and the reasons behind it--safety!

Load==
=Titegroup 5.6 grains.
=Oregon Trail Laser-Cast 180gr. RNFP.
=CCI Large Pistol Primer.
This load is mild in my rifle as far as recoil and speed. (Someday I'll have a chronograph!) I've no data regarding actual fps.

I've been shooting this load for over ten years now, thousands of rounds through the old rifle. Sometimes I get the itch to put more powder in the case to boost the performance for deer hunting, but so far, I haven't gone beyond the 5.6 grains.

When I look at the Powder Burning Rate charts, Titegroup is one of the faster burning ones.

SAAMI==.38-40 Win -- 14,000 cup

Hodgdon Data==180 GR. CAST LRNFP Titegroup 5.0 gr. 819 fps 7,000 PSI
6.4 gr. 990 fps 13,300 PSI

Do I need to be concerned with the pressure spike from such a fast powder?

Would the old rifle handle a load of 6+ grains?

That's a hard call to make. From an article in Shooting Times, July 2001 page 66, "Cimarron Model 1873 .38-40" Mike Venturino writes that he has tested the Cimarron rifle along with his Winchester '73 (circa 1900) using Oregon Trail 180 gr. cast RNFP bullets with 6.0 gr. of Titegroup. Velocities were slightly over 1200 fps and 25 yard accuracy about 1.00". But the question comes to mind, did Winchester make any metalugical changes from 1885 to 1900? If not, my inclination (if I had your rifle) would be to increase the load incrementally up to, but not exceed a 6.0 gr. load. You will have to decide bearing in mind that each rifle (especially one that old) is a separate entity and to assume what works in one will work in another could be a mistake. This is the most honest reply I can give you.

Thanks Marshal.

I'm hoping more people will chime in here with help. In the mean time, I'll keep trying to find more to read on the subject.

UncleNick, Do you have insight regarding this topic?