S&W .357 Snub - Cast Bullet Accuracy---

[Prince55]

Recently a friend who is concerned that he might not be able to get any
more ammunition for his .357 S&W 2 1/8 inch snub nose asked me to
reload him some to keep on his farm.
I also have a S&W model 60-9 like his and went to testing some loads.
The first was a load from the old Speer #8 manual for .357 snub nose revolvers
and I used the Hornady XTP 140gr bullet with 8.5gr of the New Unique
powder at 35 ft. into a metal bullet trap. The accuracy was Great- with
groups being in the 1 3/4 inch size, but I noticed some of the primers
were blackened around the firing pin impact point.
Next I tried some of the Dardas 125gr round nose cast flat point bb cast
bullets with 9.5gr of Unique and the Federal # 205 Small Rifle Primer and
the groups shrank to less than 3/4 of an inch.
My question is ---What is the main difference between the small pistol
primer and the small rifle primer ?
This is about the fifth time that I have had superb accuracy results with
the Dardas cast bullets.
Anyone have any reasoning for these results with the two different
types of primers in the .357 cartridge?

Thanks

[joneb]

-What is the main difference between the small pistol
primer and the small rifle primer ?

The small rifle primer has a little hotter charge, but not as hot as a small pistol magum primer. The small rifle primer's cup(shell) is thicker to handle higher pressures. Some handgun main springs are not strong enough to reliably set off a small rifle primer.
Have you tried small pistol magnum primers ?

Anyone have any reasoning for these results with the two different
types of primers in the .357 cartridge?

Possibly better powder ignition.

[Sport45]

Unique shouldn't need a magnum primer to light off even in .357mag loadings.

What primer did you use with the first loading? It sounds like you had piercing if the black was only found around the impact point. Did you get any piercing with the rifle primer? You might want to check the firing pin to make sure the end isn't damaged.

Recently a friend who is concerned that he might not be able to get any more ammunition for his .357 S&W 2 1/8 inch snub nose asked me to reload him some to keep on his farm.

If I was reloading for someone else (I don't), I would not vary one iota from a published minimum load with the bullet and primer clearly identified. I would reference the load data and where it came from on the packaging.

[Prince55]

Thanks for all answers.
It seems like the small rifle primers were much more consistent.
The primers used on the first loads were the Remington # 1 1/2
small pistol primers. No, the small rifle primers we not pierced.
I carefully checked the firing pin and it's not too sharp or pointed.
The first primers were clearly slightly pierced as seen looking through
a magnifying glass and also you could blow hard through them and feel
a small amt. of air coming through.
The small rifle primers after firing were slightly caved in at the center
around where the firing pin had hit-not the normal dimple made on a
regular pistol primer. You could tell the primer cup was made of thicker metal.

Thanks Again

[joneb]

Prince 55, did you start at max ? your loads seem to hot I would reduce by 10% and work up.

[WESHOOT2]

Pierced primers = your load is too heavy.

[joneb]

You could tell the primer cup was made of thicker metal.

And is less likely to show signs of over pressure, did the shell cases extract easily ?

[Prince55]

Actually it was only one primer that was pierced of the Remington
# 1 1/2 and I had worked up and the cases extracted easily.
Guess it could have been something about that one primer.
The loads in the old Speer # 8 manual are sometimes a "little" warm.
Also one of the chambers could have been a slight bit tighter.

[joneb]

A recipe for over pressure loads ?

loads in the old Speer # 8 manual are sometimes a "little" warm.

Thats a understatement some of the starting loads in the Speer #8 are max loads in other manuals, and then there's the difference between "new Unique" vs old Unique.

[awaveritt]

Not to highjack the thread, but I have a number ten Speer manual. When did manuals start to "dumb-down" certain loads? Or has it been gradual?

[Unclenick]

Awaveritt,

It's mostly lawyers and liability. The SAAMI maximum recommended pressures were reduced for many rounds, the .357 and .44 magnums, in particular. The .357 was reduced almost 30%. The commercial ammo makers often load well below SAAMI max for an extra safety margin. The load manuals all came down, too.

Mostly that happened in the '90's. However, in the case of the manuals, I would not be too quick to call it "dumbing down". Not only the Speer #8 and it predecessors, but my old Hornady Second Edition manual, too, has some loads in it that are unsafe in some guns even at their starting load levels. I put one of their starting loads of 2400 together in .44 Special and fired it in my Charter Bulldog. Sticky extraction and a palm-reddening stinging recoil were the result. The problem was the early manual makers were often just not very sophisticated about the load development process. They simply developed loads in one gun and assumed they were fine in other guns with the same chambering. They might develop a .357 load in a Ruger Blackhawk, but never try it in a light snubby. This is one reason the Lyman manuals developed a good reputation. Most of their loads had pressure test numbers, when the others often did not.


Prince55,

I couldn't connect what you were asking to the load description in your original post? You say the primer is the only difference, but you listed a different bullet weight and constructio and a different powder charge, which are all more significant differences to accuracy. Snubbies (especially the 1 7/8" barreled guns) often exhibit terrible muzzle velocity variation because the muzzle is too close to the bullet's peak pressure position. In a thread on another forum we had a fellow getting velocity extreme spread of 150 fps with an average velocity of about 525 fps. Not good.

A little difference in start pressure or primer flame distribution causes the bullet position at peak pressure to vary a bit. In a longer barrel that is somewhat compensated for by resulting faster or slower pressure drop as the bullet goes further down the tube. So, getting the pressure peak to occur earlier in bullet travel helps mitigate the problem in a short barrel, and running a warmer primer helps with that. With short handgun barrels you want to run the fastest powder with the hottest primer you can that safely combine that fives acceptable performance.