Stupid question of the week: .357 magnum data questions

Status
Not open for further replies.
1KPerDay

1KPerDay

Member
Joined
Jan 19, 2006
Messages
20,871
Location
Happy Valley, UT
So I'm gearing up to start loading my first .357 Magnum loads. I ordered some coated 158 LSWC from MBC and got a few 158s and 140s sent to me gratis by Dudedog (thanks again, man!).:cool:

1. Why is FMJ/JHP data generally so much hotter than LSWC data? It's like 2X the pressure in some manuals. Lead velocity seems to max around 1200 fps for 158s while jhp maxes closer to 1500. :confused:

2. Why would the data for, say, HP-38 max out at 21-24,000 PSI while the data for HS-6 or 2400 or H110 or a "more suitable magnum powder" max out in the 40K range? What other than pressure is the concern? Why did they stop at almost half the pressure max and set the max load there?

3. Hodgdon data is typically X to Y charges for Lead, and Y+1 to 2 grains to Z (Y+3 to 4 grains) for JHP. So the starting charge for JHP is higher than the MAX charge for LSWC. (Lyman's data is a bit more consistent across lead/Linotype and JHP loads but still a bit higher for JHP.) Why? What are the concerns with lead bullets and higher pressures? Leading? Anything else?

4. For coated LSWC, I assume I stick to lead data, right? I want some entertaining .357 magnum level thump and blast otherwise I'd just load .38 Specials.
 
I have been loading the hp-38 in the .357 for several years.

I load them for my father. For targets, he likes the 3.5 grn load. Good thump with nice recoil. Fires like a +p load he says. You can increase load to, around 4.25 grn of hp-38. I would have to look at my notes to see max load that I have used.

Hp-38 is rather fast burning. Not giving enough time to develop pressure.

Also, everything k load is fmj. I load mainly for target. (I usually buy my self defense loads.) also, the 3.5 grn hp-38 is also good for snake/rat shot. I don't use shot cups, just an over powder card and two over shot cards sealed with wax. Using #9 shot. Makes good pattern inside of 10 feet. (Perfect for no legs)


Sent from my iPhone using Tapatalk
 
Last edited:
1. Lead has a speed limit. Speed limit is dependent on the gun, but it typically is in the 1200 fps range. Anything faster and you cause lead buildup in the barrel at a very accelerated rate. This is because lead is soft and you actually strip it off the bullet like smearing mud down the bore. Copper jackets are designed simply to stop that from happening. Think of the copper jacket as a bushing between the lead bullet core and barrel.
 
2. Different powders act differently. A lot of powders spike really high suddenly at a given point which can damage the gun. Sometimes powders are just so bulky that you max out with a full case. It's not all about pressure or burn rate, it's a factor of both, and the reasonable limits of most guns.
 
3 is tied to 1.

4. For coated you can get by running a bit hotter but not a lot. It's still about leading. You can get some serious thump with lead if you load it properly.
 
Based on my studies, IMO, non-gas checked lead bullets reach their maximum effect other than more boom, blast and flash at about 1000 fps. You need a hot enough load to obturate the base, stopping hot gases from leaking past the bullet, and leading the barrel something fierce. Plated bullets mostly are rated at ~1200 fps, and after that , there can be problems.

You want Boom and Thump? Try Skeeter Skelton's "medium" load of 13.5 gr 2400. :what:

For plenteous B & T, and good accuracy, my old IPSC load of 5.5 gr. Unique, .38 or 357 cases does fine. 860 fps from a 4" barrel. Not quite major, but if you shoot good enough, no biggie.;)
Or, find a near-max load in any manual, and let 'er rip!
Good luck! :)
 
Bevel base coated lead pills still need to obturate? Does whatever obturation occurs compromise the coating? will I get airborne lead and/or leading in the barrel?
 
Lead data is generally lighter to prevent leading of the bore. Hitek and powder coatings pretty well solve this problem. I shoot 158(164gr as cast) powder coated lswc using 158gr xtp data no issue. The softer coated lead bullets will also go about a hundred fps faster than jacketed bullets with the same charge. My 357 brass is designated to only thumpers. Mostly mid range (15.7gr) H110 loads. 1342fps from a 6" revolver and 1751fps from 16" levergun.

Max lilgun loads of 18+gr are a real hoot but I reserve them for the levergun only. Have shot a few through the revolver just for science. 6" revolver 1553fps and 16" lever 2,000fps on the dot.

Im using clip on wheel weights for my alloy. about 11-12bhn.
 
The coating will not be effected by the bullet slightly expanding to fill the barrel. When I first bought coated 9mm bullets from the MBC I tested them to see how well they hold up. I pushed them hard trying to make them fail and lead the barrel, I could not. I loaded a 124gr bullet over a full charge of Longshot for velocities of over 1200 fps from a 4" barrel and no leading at all.

Just a note, when firing lead bullets most if the smoke you see is not from the powder and is not lead smoke. It's the lube burning off you are seeing.
 
1KPerDay said:
So you get 2000 FPS with coated lead and no leading?
Click to expand...
Correct. Using powder coating. Hitek bullets may or may not be able to hold up to that velocity, I hear it cant be pushed as fast as powder coated bullets but those max out at ~2600fps.
 
Short answer: most of the manuals are assuming you are using swaged lead bullets, which being soft will not hold up to high pressure/velocity. Get a Lyman manual that has load data for cast bullets.

Don
 
Bingo!. :)

What powder are you looking to use? What power level? I am shooting a Hi-Tek coating 158 Gr SWC at an average 1250ish FPS from a 4" 586. I have tried SNS and ACME, and the MBC bullet is probably the same exact bullet (Magma mold).
 
Care to share that load? I will confirm with published data. Also do I need magnum primers if using "regular" handgun powders?
 
Okay, thanks. HS-6 does okay in 9mm and other pistol cartridges with standard primers... is the larger capacity the reason for magnum primers?
 
I suspect it's the larger case, but HS-6 definitely prefers magnum primers in .357 brass. It's a great choice for those 'more than .38 - less than full magnum' loads.
WSPM primers seem to work best with HS-6.
 
Will HS-6 work with a standard primer? Of course it will but it works better with a magnum primer. HS-6 also likes to be loaded in the upper end of the pressure range, it just does.

You will hear some say magnum primers are not needed, they load with a standard primer all the time. I'm sure they do but they also never tried a magnum primer to see if it produces a better round.
 
Lead data is very conservative based on the premise that unless the data specifies somebody's name brand lead bullet, they have no idea how close your lead or cast bullet is to the one they tested. Lead bullet upper limits are based on where they are guessing that "leading" will occur, and not based chamber pressures. In most cases, lead bullets will produce higher velocity and lower chamber pressure than a jacketed of equal weight and size.

I don't use coated bullets, but I can personally attest to the fact that Missouri cast 18BRN uncoated bullets shoot clean and accurrate with full power jacketed loads of Unique, Blue Dot, or 110/296 in my GP100, and my Redhawk 44 in the 1200-1400 fps range.
 
Load data seems to change year by year, which is confusing to say the least. My hand cast gc swc bullets - 156grns but casts 160 plus with WW - with 15 grains of 2400 gives 1450 fps in my S&W M28 and is extremely accurate. Admittedly this is a hot load and is reserved for special use. For everyday I load the same bullet over 12.5 grains of 2400. This load is also very accurate and gives 1150fps to 1200fps depending on the revolver. The loads using 158 grain HPs gives a little over 1250fps and is a good hunting load. That's with either Blue Dot or 2400.
 
A 158 grain lead bullet at 1200 fps is generally a nice load. Give it a try. :)

With the right powder you can go up to about 1500 fps; the bullets may or may not be able to cope with that, depending on a lot of factors.
 
I actually tested a few of these MBC coated 158gr LSWC bullets in 38special and using Power Pistol. I had loads from 5.5gn to 6.0gn with accuracy from .85" to 1.5" at 10 yards. My test pistol was a 3" Ruger SP101. Following are the results from the lowest and highest charge I used. At 6.0gn there was some flattening of the primers, but no sticky cases:

38spl
COL: 1.475"
MBC, 158gr, B18HTSWC, PowerPistol, 5.5gr, WSP
Average: 874
ES: 39
SD: 15.6
Force: 268
PF: 138
Velocities: 892, 886, 853, 873, 866


38spl
COL: 1.475"
MBC, 158gr, B18HTSWC, PowerPistol, 6gr, WSP
Average: 960
ES: 21
SD: 9.2
Force: 323
PF: 151
Velocities: 946, 967, 966, 955, 966

In 357magnum using the same bullet, my load closest to the 6.0gn 38special load is a 6.5gn load. The velocity is very similar and the accuracy is very good.

357mag
COL: 1.620"
MBC, 158gr, B18HTSWC, PowerPistol, 6.5gr, WSP
Average: 965
ES: 33
SD: 12.3
Force: 327
PF: 152
Velocities: 964, 965, 952, 985, 959
 
Lol, we only have one stupid question per week now? Wow things really improved when I got out of the way:D
 
Status
Not open for further replies.

Similar threads

M
  • Locked
Questions about. 357 mag reloading data
2 3 4 5 6
Replies
147
Views
8K
Mixed Nuts
M
T
  • Locked
This dont make sense
Replies
15
Views
3K
therealwormey
T
Quoheleth
  • Locked
.357 Mag start loads: help please
Replies
9
Views
698
joneb
joneb
0
  • Locked
Question about lead bullet loads
Replies
7
Views
499
ljnowell
L
E
  • Locked
SAAMI vs. Hodgdon pressures
Replies
10
Views
925
Ol` Joe
O
Back
Top