357 158 gr bullet velocity swings with 2400?

[kennethdlarson]

All,
I was just out shooting my 6" M28-2 with a load of 15.0 grains of Alliant 2400 on top of a CCI 500. Bullet is an Xtreme 158 gr. hollowpoint. I was getting velocity swings from 1100 fps to 1300+ fps. The average was around 1200 fps. Just wondering if someone out there has had this happen to them.

In another load with the same bullet, shooting 16.0 grains IMR4227 on top of a CCI 550 for about 1200+ fps I was not getting the velocity swings that I had with 2400.

Any info is appreciated and thanks!

 

[Rogeronimo]

I suggest reworking your loads up with magnum primers. Both my Speer and Hornady books recommend this with 2400.

 

[Joed49]

When I learned to reload I was taught to use magnum primers for loads over 8 gr. Don't think I've ever seen 2400 loads with a standard primer.

 

[kennethdlarson]

Thanks for the replies. I used the Alliant website as guidance for the CCI 500s. I've see recommendations on this and other forums against mag primers with 2400. Not calling anyone out, just additional info for the thread. Reworking load advice taken and thanks!

 

[rockquarry]

Magnum primers aren't necessary for use with #2400, though they hurt nothing. Probably best to use the primer that provides best accuracy, but often the difference, if any, is so slight that it's difficult to determine.

I've loaded the .357 for decades using #2400 with jacketed and cast bullets and magnum and standard primers and fired such loads in many revolvers. I have never experienced the wide velocity variations you mention.

Are you using a proven and reliable chronograph? Good luck-

 

[Rpg]

I always use magnum primers in 2400 loads for the 44 mag.

 

[patjmc]

I found I had pretty wide swings with standard primers while I was working up my 2400 158gr loads. I reworked them with Magnum primers and they settled down nicely for me. YMMV

 

[kennethdlarson]

Chronograph is a Shooting Crony F-1. I was out load testing my left hand Winchester M70 26" 7mm Rem Mag with the same chrony and found "my load" - 63.0 gr of IMR 4831 behind a Hornady 162 gr. ELD-X on a CCI 250. .75" at 2900 fps - good in my book...

 

[andyo5]

I have repeatedly found better accuracy with Federal Standard primers vs. Federal Magnum primers. But I can't vouch for whether velocity spread is tighter with one or the other. I am more concerned with repeated point of impact.

 

[Ben_hutcherson]

Just to address a possible elephant in the room, from what distance are you shooting the loads over the chrono?

I've found 2400 to be particularly bad about giving false readings if you are too close.

Aside from that, I have switched almost exclusively to Federal Match primers(I stocked up on them a while back when they were on sale, so am working out of that) and 2400 shoots great for me using a regular SPP.

 

[kennethdlarson]

I was shooting over the chronograph at about 3-4 yards. Too close? I was not using the sky screens.

 

[kennethdlarson]

Given the same bullet weight and powder, what charges is the peanut gallery using?

 

[Cdog]

I don't have any experience with your particular load. My first thoughts, uniform start pressures.

Check for light or inconsistent crimp.

.

 

[ArchAngelCD]

Magnum primers are not necessary when loading with 2400. In fact like mentioned above 2400 performers better with a standard primer.

OP, are you sure you didn't have the chrono too close to the muzzle? The muzzle blast can cause errors in testing.

 

[Pisgah]

I don't have any experience with your particular load. My first thoughts, uniform start pressures.

Check for light or inconsistent crimp.

.

Amen. I have found that a consistent, heavy crimp makes a whale of a difference with 2400, regardless of the cartridge I am using it in.

 

[ParadiseRoad]

I don't have any experience with your particular load. My first thoughts, uniform start pressures.

Check for light or inconsistent crimp.

.

...I agree...inconsistent crimp varying the pressures...

 

[Alk8944]

Something no one mentioned, and most will likely argue about, is hammer energy. With the great popularity of doing "trigger jobs" on revolvers to get light trigger pulls no one seems to give any concern to the fact that primers need a certain minimum energy to give consistent ignition to the primer. The common belief is that if the primer fires everything is OK! This is not true. Light strikes do not give consistent initiation of the primer, even if the primers always fire.

Has your mainspring been replaced with a "reduced power" spring, or has the strain screw been shortened or loosened? If any of these is the case try restoring the gun to factory standards and see what happens to velocity consistency.

Naturally crimp consistency can be a factor too, although generally not showing such a wide velocity range as you indicate. Try a Redding "Profile Crimp" die and see if this helps too.

 

[iPac]

Thanks for the replies. I used the Alliant website as guidance for the CCI 500s. I've see recommendations on this and other forums against mag primers with 2400. Not calling anyone out, just additional info for the thread. Reworking load advice taken and thanks!

I never use magnum primers with 2400. I use Winchester and with those there really is no need for magnum primers.

I would check to make sure you chrono was reading accurately and it wasn't lighting messing with it. Other than that, I don't know why you would have that big of range. Unless you have very dirty shells with clogged primer pockets perhaps. All of my loads with 2400 are always very close together chrono wise.

 

[ArchAngelCD]

I never use magnum primers with 2400. I use Winchester and with those there really is no need for magnum primers.

That is only true with LPP from Winchester not SPP. Since we are talking about it the .357 Magnum if you want a magnum primer the Winchester SPP won't fill that bill.

 

[Davinman]

i load 158gr lead swc's w/15.2gr. 2400 and they shoot fantastic with win. small pistol std primers, no need for a mag primer