.357 180-gr Loads with K77/357 rifle

[Warthog]

I've read the K77/357 is more accurate with heaver loads. So I wanted to work up some loads with the 180 gr Hornady XTP. I'm using Vihta Vuori N110 powder which I believe is very good, but expensive. I have a couple of questions I would like your opinion.

The Vihta Vuori reloading manual #4 (1/2007) recommends small rifle primers for .357 due to the long and narrow powder column. The Vihta Vuori Reloading Guide #6 (7/2008) uses small pistol primers, with the same 14.0 gr giving 1394 fps (7" barrel), which is the same load and fps as the #4 manual with a small rifle primer!

Hornady in it's .357 rifle section uses a Winchester WSPM, which is a small magnum pistol primer. This seems in line with the VV using a small rifle primer. However Hornady's maximum load is 11.9 gr for 1400 fps out of a 16 inch barrel, almost the same fps as the VV 7" test barrel.

Speer reloading manual #14 states that the .357 using VV N110 works great with standard CCI primers! They do not have a 180 gr bullet, but the 170 gr max load is 13.8 gr to get 1579 fps from an 18 inch barrel.

I tried the Hornady load with 11.9 gr of VV N110. I averaged 1415 ft/sec using CCI small pistol magnum primers. The CCI BR-4 small rifle match primers gave 1404 fps.

I guess it is not fair to include the speer 170 gr in this mix. I compared Hornady, Speer, and VV at 158 gr,

Hornady 13.4 gr 1600 fps
Speer 15.0 gr 1738 fps
VV 15.9 gr 1569 fps (7" barrel)

I would like to know if using VV number is "pushing it too far". I'm not using a old lever action, just the K77/357 bolt action, or my Smith revolver. There doesn't seem to be much difference between a small rifle or the small pistol magnum primer with this slow burning powder.

My question is which way do I go? The maximum load 1 grain different, and i'm not sure who to believe on primer selection.

Please comment.

Warthog

 

[mattsbox99]

There just isn't much difference in primers. I just buy small rifle primers and use them in both applications. Large rifle and pistol are different heights so I can't mix them.

Is your load accurate?

 

[Warthog]

There just isn't much difference in primers. I just buy small rifle primers and use them in both applications. Large rifle and pistol are different heights so I can't mix them.

Is your load accurate?

I don't know yet. I was shooting through the Chronometer at a target, and I started with the recommended starting load. As this had some drop to it, I hit the target support so all I got after that a velocity data. I need to try again.

Warthog

 

[WESHOOT2]

I found my best results with N110 in 357 Magnum using CCI500 primers.

 

[Warthog]

I found my best results with N110 in 357 Magnum using CCI500 primers.

Thank you for your response. I am guessing that Hornady saying that slow burning powders need magnum primers may be correct for some, but not for VV N110. Maybe they didn't even try a standard primer. I read that slow burning powders have a coating to control the burn rate. Maybe the coating on the VV N110 is easier to light that other powders. I sure like it.

Warthog

 

[mattsbox99]

Generally ball powders and any charge over 50 grains should use a Magnum primer. Its definitely not necessary in a .357 Mag, but I haven't used VVN110 so I can't comment on how well it runs.

 

[jrc270]

I have been using N110 for about 10 years for both 357 and 44 magnum loads. The primers I used were based on the VihtVuori 3rd edition printed manual era... Federal 200 and 155 primers.

I then got the 4th edition printed manual... Small rifle primers for 357 and large pistol primers for 44 mag... their on-line data list the small and large pistol primers as you said...

I emailed VihtaVuori with the question... which is correct ?

The answer returned was... small pistol for the 357 and large pistol for the 44 (just like Speers #14 book).

Since the primer shortage of 2009, I have changed to CCI 300 and 500 primers with no appreciable change in chronographed persformance.