357 Magnum Light Loads - Good or Poor Choice

[03lover]

I am a bullseye shooter and enjoy using cast boolits and light to mid range loads. I am also very particular about accuracy. I like to shoot my 357 magnums in addition to my 38 specials and many other handgun calibers.

The problem I have with the light to mid range loads in the 357 magnum is consistent accuracy. I was getting groups with great clusters and a few shots out of the group.

I decided to start chronographing all my load testing. I found the loads that used less than 75% of the available space for powder to be the problem. Loads using 50% or less available space were much worse. Powder position is the problem.

I performed hundreds of tests with many different powders, primers and bullets. I fired with the powder to the rear and powder to the front to see what the difference may be. I found an average of 100 fps to 250 fps changes in velocity with the powder to the rear always the higher velocity. Extreme spread also varied greatly. The groups fired varied the point of impact on the target at only fifty feet, from around 1" to over 2" powder to the rear vs powder to the front.

I have tried many powders said to be less position sensitive, but not much less.

I realize plinker type shooters are probably not interested in this, but if anyone is being troubled by groups that are pretty good except for a few flyers, you may want to consider this powder position may be the problem.

I haven't found a good fix for the powder position problem with light to mid range loads in the 357 magnum. If I make an effort to position the powder to the rear before firing, groups are great. This isn't always possible. Fillers can work but add to the time and cost of reloading.

The bottom line is if the shooter reloader is aware of the problem, avoiding the worst extremes of powder position will tighten the groups or increas the number of hits.

[44man]

Longer brass was never designed to shoot .38 loads with the same powders. If you want light loads in the .357, find a powder that fills the case more. No need for mag velocity but powder choice is what you need to look at.
Even the .38 with the wrong powder will show the same results.
The boolit is important, a wad cutter in the .38 is deep in the case so a pinch of Bullseye is far different then with a Keith.

[jameslovesjammie]

Did you test Trailboss? Trailboss is a revolver's best friend with low to mid power loads.

[L Ross]

Trail Boss may solve your problem.

Duke

[03lover]

All good points and Trail Boss is the bulkest powder for the job.

I am well aware of the problems using 357 magnum for light loads, but I keep hoping I can find the magic combination. I am sticking with the 148 grain wad cutter and HBWC for the light loads to fill as much of the free space as possible.

I tried Trail Boss once, going from 3.2 gr, to 4.0 gr. but grouping was a bit erratic and velocities ran from 753.9 fps to 779.7 fps. One group tight the next opens up with the next powder charge tight again and so on. With small increases with each powder charge I expect to see some kind of regular progression of groups getting better or worse and the five powder charges of Trail Boss I tried made choosing the best difficult. I don't like to see erratic with small increases of powder because the slightest variation can mess up the group sizes.

The trail Boss is worth another try using three different primers to see if one brand works better than another. The velocity range I was in with the Trail Boss was good for the HBWC. I am not sure lower or higher will be better. If all else fails, I can try.

[zxcvbob]

Great light-to-mid .357 Magnum load: 148 grain DEWC and 4.5 grains of Red Dot or Promo. Crimp in the crimp groove, not over the top (OAL will be somewhere around 1.35") I just loaded a batch yesterday.

[paul h]

Can't provide a solution that's worked for me, but it sounds like a good explanation why my 357 will shoot 3 or 4 into 1 ragged hole at 25 yds and throw one of two shots an inch or so out from the group. Also explains why my 480 shoots steller groups will full patch loads, but trying to back off loads to target levels i.e. 700 fps has resulted in mediocre accuracy.

The long and the short of it is that I believe too much air spare results in inconsistant ignition and hence inconsistant accuracy.

[white eagle]

ever thought about some dacron filler
will keep powder where you want

[btroj]

Why shoot the light loads in magnum brass? That is what special brass is for.
If I use magnum brass then I load Irwin magnum loads. Low to mid level loads are put up in special cases.

Seems to me ou are looking for a solution to a problem that need not exist.

[Thumbcocker]

Another vote for 4.5 of red dot.

[zxcvbob]

Why shoot the light loads in magnum brass? That is what special brass is for.
If I use magnum brass then I load Irwin magnum loads. Low to mid level loads are put up in special cases.

Seems to me ou are looking for a solution to a problem that need not exist.

There's a pretty big step up from top-end .38 Special loads and starter .357 Magnum loads.

[btroj]

I don't see the step as being that large. Look at Hodgdons data. 38 +P goes 950 fps with a 158 jacketed bullet.. 357 start loads begin around 1000 fps for same bullet depending on powder.

use the old 38/44 data and we get even closer to 357 start velocities in a special case.

[zxcvbob]

I don't see the step as being that large. Look at Hodgdons data. 38 +P goes 950 fps with a 158 jacketed bullet.. 357 start loads begin around 1000 fps for same bullet depending on powder.

use the old 38/44 data and we get even closer to 357 start velocities in a special case.

I actually put that wadcutter load in .38 Special brass, but I load them to .357 lengths. They look kind of silly with the wadcutter bullet sticking halfway out the case, but they will not chamber in any .38 Special that I've tried and that's a good safety feature.

I used to load 38/44's for my Marlin and paint the case heads with a red Magic Marker and write "Danger! Rifle Only" on the box, but I decided after I'm gone some idiot future grandkid of mine might get ahold of them and shoot them in a pot metal RG revolver or something. I guess that's still a possibility with the long wadcutters, but only if the gun has the throats bored out to get rid of the step at the start of the throats -- or he hammers them into the chambers.

It's safest to use .357 brass for any high pressure loads.

[Salmoneye]

Another vote for 4.5 of red dot.

+2

[got_lead?]

OK, so here's a suggestion, take it or leave it. Seat deeper in the case. With a revolver, there's no problem seating Nagant style, with the boolit shoulder below the case mouth. I use this method for 120 grain boolits in my S&W model 52, which requires that any boolit is seated below the mouth. And this load of 2.8 gn bullseye behind a 120 grain TC shoots like a target pistol out of my snubby as well. Seating deeper will increase powder efficiency too, just don't seat too deep for the boolit weight. Consider the length of the cartridge to be from the rim to the nose of the boolit, wherever it's seated, as long as the COL and the load are copasetic, your'e golden.

[btroj]

I only own modern, strong 357s so safety factors aren't an issue for me.

I generally have 2 levels of 38/357 loads. I shoot mostly low end 38 special lands or full on mag loads. I don't have much need for middle ground loads.

[03lover]

Lots of good suggestions. Thanks.

I will have to try the 4.5 gr. of Red Dot and deep seating the bullets.

My Red Dot is about 55 years old and hasn't been used since the mid 60's. I'll check it out and if it still looks good I will load ten rounds to see how it performs in a 5-1/2" barreled Ruger. I may have to pick up a small can for load developement.

I like the idea of deep seating the bullet over shooting 38 Spl. in a 357 magnum. Same amount of jump but the bullet will be better supported before entering the cylinder throat. A note of caution is needed here. Because the brass gets thicker toward the base a person wouldn't want to seat a bullet too deep or it will be undersized by the brass.

It is easy to determine where the top of the powder charge is and that can be where the base of the bullet should be to eliminate powder position problems. I will report the results of my testing when completed.

[zxcvbob]

I will have to try the 4.5 gr. of Red Dot and deep seating the bullets.

What bullet are you talking about "deep seating"? 4.5 grains is a lot of Red Dot, if you stuff 158's down in the case with the nose flush you are likely to blow yourself up. With 125's it's probably OK.

[subsonic]

I've had good luck with 700x in .38's in a .357. Generally, people will say that you'll get better accuracy with a .357 case in a .357 chamber, but I wouldn't take that as a hard and fast rule.

I have some .38s loaded with 148gr Lee wadcutters over 3gr of 700x and the last group I shot (6 shots) at 25yds was right at 3/4" from my 686 .357. All the other shots (while sighting in) were right where they should have been from the adjustment. I need to experiment further, but maybe this will give you some direction and hope.

[rhbrink]

+2

+3

Richard