Reloading help please

[Renegade Master]

Hi Guys,

I have been reloading .357 for my Marlin for a couple of years now and have developed a load that was fairly accurate.

Recently I decided to try a different bullet shape. I usually use a RNFP but decided to try semi wad cutters for a change. I used the same load as I always have (5.0gns of DO32 and 158gb bullet), and the only things that changed were I had to seat it slightly deeper (although OAL remained the same) and I gave it a touch more crimp, probably less than a 16th of a turn.

Shooting on Sunday I found my groups were awful, they had opened up to several inches. Tried a few of my old loads though (with the RNFP) and they grouped OK. What I'm wondering is why this slightly amended load has gone so wrong, and what I can do to improve it?

Any and all advise, as always, appreciated.

[Turnup]

Back in the pistol days, I and a number of my fellow shooters found that light target loads were very sensitive to crimp. Too much crimp gave relatively wild results, so first off I would suggest that you back off the crimp and see. I have also found that in my Marlin, the difference between RNFP and TC bullets give a noticeable difference in group with no other change (for me I was using TC, and tried RNFP), I did not further explore a good load for the RNFP and simply went back to TC. A buddy of mine reports that he finds RNFP better than TC in his Taurus, so this seems to be a sensitive change. We both are using much lower loads of D032 @25 yds, we find 2.9 grains works well in the Marlin and about 3.3 grains in the Taurus.

[Renegade Master]

Thank you for that. I did wonder if the crimp might be responsible, I will back it off as suggested and try again. Cheers.

[DaveC]

The difference between the RNFP and the semi wad cutters could be more than just shape. I assume both are cast lead, are they from the same manufacturer? same lube, and sized the same? I use TC 158g in my Marlin and hade different results with them from different manufactures.

Just a thought

Dave

[Renegade Master]

Both 158gn GM Hardcast lead, I assume the same lube??

[Harrympope]

I have owned over a dozen different 357 caliber semi wadcutter bullet molds. In my guns only one or two of them shoot,the rest of them are pure garbage. Even the same design but cut at different times will not shoot as well as the other. I think the semi wadcutter design is just rather finicky. The one that shoots the best is a lyman 358156 with the RCBS 180 siloutte very close. I find that round nose bullets or round with flat to shoot better in general. There are exceptions of course but I find I don't fight with the semi wad-cutters much anymore.

[Renegade Master]

Cheers for that. Sounds like I had better stick with what I know works.

Anybody want to buy 400 semi wad cutters?