.38 SP. & .357 Magnum bullet diameter

[rockquarry]

For many years, I've run all my .38 SP. and .357 Magnum cast bullets through a .358" or sometimes even a .359" size die. Wheelweight alloy bullets come out about .3575" when I use the .358" die. In the the .359" die, they wind up at about .3585". I've been experimenting with a .357" die off and on for a few years. Bullets come out about .3565" or a bit more, but always slightly under .357". With a slightly harder alloy, bullets measure what they should in each respective size die.

I realize many would not go to the trouble to load up two different diameter bullets and that makes a lot of sense, but I've wound up with such a variety of .38 Special and .357 Magnum revolvers over a long time that it's worth the trouble for me, particularly when I can see the difference on the target.

I was shooting this morning, comparing the accuracy of bullets that were sized in the .357 die vs. those that were sized in the .358" die. My load was the 160 grain SWC cast from an H&G #51 4-cavity mould. I use CCI SP primers in Starline, Remington and PPU brass and 4.3 grains, 231. MV is around 860 fps from a 6" barrel and about 725 from a snubnose gun.

I fired several boxes offhand only, single-action at 25 yards and measured nothing, but in most instances, it was easy to see which revolver preferred .357" bullets and which liked .358". I had already fired the same loads from benchrest a week ago, so pretty well knew what to expect.

I still have much work to do, but generally, my J-frame .38s are noticeably more accurate with bullets sized in the .357" die. K-frame and N-frame guns vary as to best bullet diameter. The recommendation that a cast bullet should pass through a chamber throat with very slight resistance remains good advice generally, but you need to shoot groups to make sure.

 

[Qc Pistolero]

Your last phrase pretty well sums it all up.

 

[trapper9260]

Have you check the cylinder for the dia. of what size boolit will fit snug that you can push it by hand ? I normal size my the same as you ,I see I will see about to do some .359 . Each gun will tell you what will work the best.

 

[Fishslayer]

I just wish I was skilled enough to notice bullet to bullet accuracy differences in my J frames.

 

[oddshooter]

I just wish I was skilled enough to notice bullet to bullet accuracy differences in my J frames.

It's fairly easy, but it takes time and patience.
I use bench rest, leather bags, scope, chrono, and 25 yards.

I keep shooting logs ! ! !
I use many 357mag diameter bullets from many manufacturers.
One size NEVER fits everything. Cylinder and groove diameters vary too much between wheelguns.

I use many powders.
For a single powder:
I handload a single bullet with 5 different weight recipes, and capture group size and velocity for each combo (6 rounds). When done right, out of 5 weight recipes, 1 is too slow and inaccurate, and 1 is too fast (hot) and inaccurate. I like it when I surround my accuracy goal like that.
It is easy to see the accuracy change with the different power weight in the 5 combos.
I then move to the second bullet and do the entire process again all with the same revolver and powder recipes.
I have 8 bullets (148g, 158g, 180g, SWC, DE, HP, RN, or FT).

At the end, I am certain which bullet that one revolver likes best with that powder and weight.

I then start over with a second powder. (VV N340, H110, 4227, W231, BullsEye, TrailBoss, HS-6, 2400)


The truth resides in the logs.

I have many revolvers. The above process is done with each one.
When comparing the logs, it is easy to see which bullets shoot best most of the time across several revolvers.

You can reduce the testing required if you slug the barrel and use pin gauges for all the cylinder exits. That gets you started with a good SWAG (Scientific Wild AZZ Guess) for bullet diameter.


Prescut
I think my LIBRARY inventory has 240 combos for the 357mag at this point. I shot 6 rounds from each. That's almost 1500 rounds over 3 years for just the 357mag. But it's great not having to start over with each new 357 hawgleg. However, Powder Coating could get me to begin again with my Handloads. I love it and believe it to be the biggest paradigm shift for projectiles in a century.

 

[Biggfoot44]

Oddshooter is indeed very though, and is the * Correct * method, and I salute him . But for discussion purposes, I will present another approach I frequently use , more of a concept of setting and meeting a goal of " Suitable for my expected requirements " .

Cast bullet of either usual dia for cal, or rounded up .001 . Powder charge of what my experience suggests is about right .

Test over chrono . If within desired vel range, and doesn't have huge spreads, move to next step .

Shoot for group @ 25yds ( either from sandbags or 2 hand braced ) . If sub 1.25in groups , I'll declare Victory ! . If not , then fine tune to try to improve accuracy .

 

[Nevada Ed]

Spending time to see what size and type lead bullet works, takes time but
it is worth the time if you have the equipment, to do it.

Only problem..................

I also shoot jacket bullets and you need to start all over again.

 

[oddshooter]

I'm with you BigFoot,

I use your procedure many times when I'm looking for a round that is "good enough" for the task at hand. I even like your 1.25" declaration of Victory. This technique should keep you within spitting distance of 6" groups at 100 yards as well. That will handle 90% of the chores most of us have.

In the post above, I tried to show maybe half the idea of a professional bullseye shooter going through bullets, powders, recipes, and multiple handguns to find the combo that puts him/her in the winners's circle.

I tried to show the enormous effort required with the calculations at the end. 99% of the time, it's not worth it. Most of us don't shoot competition and have no such exacting need for the shooting we do. However, I got to say it is a RUSH when you can find combos that shoot 1/2" groups consistently.

I had some heart issues this year and it has kept me out of the backcountry where I do my testing. Handloading took over as a major time eater and interest. I spend hours in the garage reloading area and really love it. I enjoy the process and the attention required. I need the intellectual stimulation badly after retiring last year. I must need 40 hours of shooting/testing handloads I've built to catch up.

That's kind of my excuse for being so obsessive-compulsive about some of my handloading in tiny, small batches. I haven't gotten to the point of just building ammo in bulk, 100 or more in one session like most folks. My setup and die changes happen continually and I enjoy the challenge.


Prescut
Even more intense is as Nevada Ed says, Go to jacketed and start over. Nothings free in water world.

 

[Protocall_Design]

My load was the 160 grain SWC cast from an H&G #51 4-cavity mould. I use CCI LP primers in Starline, Remington and PPU brass and 4.3 grains, 231.

How do you get the large pistol primers in the case?

 

[rockquarry]

How do you get the large pistol primers in the case?

Corrected; thank you.