.357 magnum load help (rifle)

[6MT]

Ok fellas, I'm going to ask. I want try try 5 different charge weights in my new Winchester 1873. The bullets are lighter. They are XTP's in 125gr. The powder is H110. The barrel is a 20" with 1:18.75" twist. I know... I could do with the 158's, but I came into a lot of the lighter weight XTP's.

The brass is virgin Starline and I'm using Federal small pistol magnum primers.

The Hodgdon reloading data pages show a minimum charge weight for H110 of 21gr and a max of 22gr (rifle) for the 125gr class of bullets. Lyman regurgitates the powder manufacturer's data verbatim.

Sierra shows the min at 17.5gr and max at 19.3gr. Hornady shows a min at 10.4gr and max at 19.4gr.

Here's my plan. I loaded 5 rounds each of 16.0, 16.5, 17.0, 17.5, and 18.0gr. I know that H110 is best suited as a high end (read max charge or close to) powder. Kind of all or nothing. The cases are no where close to being full with the bullet seated.

Am I asking for some dangerous pressure spikes with the cases not being full or close to (volume wise, not charge wise)? Am I asking for a squib with the lower charge weight? How will the light duty toggle action in the 1873 react?

I need some help folks. Some guidance. I had great success with my Henry BBS in .44mag with H110. In fact I went about the load development the same way.

Or am I just over thinking this?

[Tactical Lever]

Originally Posted by 6MT

Ok fellas, I'm going to ask. I want try try 5 different charge weights in my new Winchester 1873. The bullets are lighter. They are XTP's in 125gr. The powder is H110. The barrel is a 20" with 1:18.75" twist. I know... I could do with the 158's, but I came into a lot of the lighter weight XTP's.

The brass is virgin Starline and I'm using Federal small pistol magnum primers.

The Hodgdon reloading data pages show a minimum charge weight for H110 of 21gr and a max of 22gr (rifle) for the 125gr class of bullets. Lyman regurgitates the powder manufacturer's data verbatim.

Sierra shows the min at 17.5gr and max at 19.3gr. Hornady shows a min at 10.4gr and max at 19.4gr.

Here's my plan. I loaded 5 rounds each of 16.0, 16.5, 17.0, 17.5, and 18.0gr. I know that H110 is best suited as a high end (read max charge or close to) powder. Kind of all or nothing. The cases are no where close to being full with the bullet seated.

Am I asking for some dangerous pressure spikes with the cases not being full or close to (volume wise, not charge wise)? Am I asking for a squib with the lower charge weight? How will the light duty toggle action in the 1873 react?

I need some help folks. Some guidance. I had great success with my Henry BBS in .44mag with H110. In fact I went about the load development the same way.

Or am I just over thinking this?

Very small case, and good steel; and wouldn't give bolt thrust a second thought. Your rifle is engineered to take full power factory loads.

Myself, I wouldn't start that low. Not worried about a squib, but it is a possibility that your velocities will be erratic. I'm a little surprised that the Hornady data starts that low. I'd likely start with 18 or 20 grains, as most of the data starts pretty high. Does your data reference certain cases, primers and bullets? Something to consider.

And do you have access to a chronograph? Better indicator of pressure than trying to read a small case. Might not feel when the lever is sticky, but you could tell if it is harder being pushed into the chamber with your bare finger.

All that said, your rifle has a lot more steel around the chamber than a typical revolver.

[rugerfan]

Use caution with the light charges. H110 is know to be venerable to secondary detonation in under full cases, in my experience it is best to run it on the top end of book or use another powder if light loads are desired.

[Pioneer2]

The 1873 isn't the strongest action out there.........modern or not.

[6MT]

The only reason I chose the 125gr XTP's over the 158's was that I got 3 boxes at a great deal. So I thought I would give them a try. And I chose H110 because I use it for .44mag in a Henry BBS.

I just got back from testing the first charge weights. As expected the lighter charge weights did not show very good accuracy. But....no squibs. Even with the 16.0gr charge, everything went bang.

Here's the speeds: 16.0gr 1718fps, 16.5gr 1782fps, 17.0gr 1807fps, 17.5gr 1860fps, and 18.0gr 1893. The 18.0gr seems to show the best accuracy. That's not surprising. I think the rifle will get more consistent and show a slight speed increase now that it has 45 rounds fired.

Here's what I learned and have decided to load for this modern 1873: I'm going to increase the charge weight to 18.3gr to get the speed consistently around 1900fps. And because of the 1873's toggle link action, I won't go any higher with the charge. After using the rifle for the first time, I can see why the action in the 1873 "could" have issues. So no hard cycling and no max charges.

I'm glad to hear of others using the lighter XTP's. Who knows? I may try the 158's when these 125's run out. And maybe I was over thinking this a bit. I was happy everything went bang and I had no issues. I shot a total of 45 rounds this morning.

Andy 6MT

EDIT: I have spoken to 3 knowledgeable folks who have owned this very rifle. All of them have shot literally thousands of rounds with theirs. Their approach was similar to mine. Don't over load to the max and take care of the action. But with all things in life...YMMV.