1970's Chapuis Double Express in 9.3x74R

[lkydvl]

Loading jacketed for the above is giving me some trouble. Chapuis states with 90% certainty it was regulated with Norma 285 Oryx.
I have not been able to load a 285 and get it to shoot any semblance of a group. At 100 yds I am in the 4-5 inch group size. Loading 64 grs of 4350 gives me flattened primers. I am reluctant to try a heavier charge. What powder would you suggest I try for what appears to be a need for higher velocity?
My cast loads of 285 FN regulate well at a load of 38 grs of 5744 for one shot from each barrel. The next two shots are 6 inches left and slightly higher tho group size is the same.

 

[375er]

No personal experience with it but I have read about using H380 or W760 in the cartridge.

 

[Rem700stw]

I have a Chapuis 9.3x74 SxS with a set of 20 gauge barrels of similar vintage. My load is 58 gr IMR 4350 with 286 Swift A-Frame. Used it on giraffe last year.

 

[Luvthunt]

Does not answer you question but how do you guys like the Chapuis?

 

[Rem700stw]

I bought mine because of the 2 sets of barrels. I have no complaints but I much prefer my vintage Jeffrey 450-400 and Manton 470. They just feel better in my hands.

 

[Woodcarver]

Loading jacketed for the above is giving me some trouble. Chapuis states with 90% certainty it was regulated with Norma 285 Oryx.
I have not been able to load a 285 and get it to shoot any semblance of a group. At 100 yds I am in the 4-5 inch group size. Loading 64 grs of 4350 gives me flattened primers. I am reluctant to try a heavier charge. What powder would you suggest I try for what appears to be a need for higher velocity?
My cast loads of 285 FN regulate well at a load of 38 grs of 5744 for one shot from each barrel. The next two shots are 6 inches left and slightly higher tho group size is the same.

I have a Chapuis UGEX in 9.3x74R. It was taxing my patience trying to get a load to regulate, until I used W760. Neither 4350 powders worked; or a couple others I tried. 64gr of W760 over a LR primer gives me 2320fps with the 285gr Oryx, the 286gr Nos Partition, the Woodleigh SPRN, or the Speer Hotcore. They also all shoot into the same group, with good regulation at 100yds. Hope this helps.

 

[GuttormG]

Chapuis states with 90% certainty it was regulated with Norma 285 Oryx.

Norma Oryx didnt exist i the -70s.