Help with W231 load .38 special load

[8shot]

For action pistol I need to target 980FPS with my 127gr lead plain base hollow point (power factor). The bullet is essentially the MP 360640L at .358. Right now I'm up to 4.6 gr of W231 and averaging about 860 FPS (2 different chronos).

Looks like I may need to bump up to 4.8 grains of W231....is that getting a bit extreme?

Using a K frame S&W with Clark 6" barrel.

[jonp]

Are you using SPM primers? That can tweak a load higher. I tipped a fellow worker to this who just couldnt get there and with a different slightly slower powder and mag primers made it

[8shot]

Are you using SPM primers? That can tweak a load higher. I tipped a fellow worker to this who just couldnt get there and with a different slightly slower powder and mag primers made it

The action is tuned for Federal SPP's.

[G W Wade]

Go ahead and use the magnum spp's as long as they are Federal. Switch back and forth with no problems in my guns. Most people do not under stand how difficult it is to make power factor with 38 special when using chrono and reloading manuel velocity. I went to Clays Universal for my son's 6 in. S&W GW

[8shot]

Go ahead and use the magnum spp's as long as they are Federal. Switch back and forth with no problems in my guns. Most people do not under stand how difficult it is to make power factor with 38 special when using chrono and reloading manuel velocity. I went to Clays Universal for my son's 6 in. S&W GW

Having enough trouble locating small pistol primers...going to up the powder tomorrow.

Thanks for your input.

[Kosh75287]

In a 6" barrel, couldn't you just use a slower-burning propellant? I'd think that a slightly higher charge of Unique or Herco would get you there, with or without magnum primers.
If memory serves, the two propellants I mention are more bulky than W231, and may buy you a bit more uniformity, from increased loading density. Not sure of that, but wouldn't be surprised.

[dannyd]

With 231 using a 125 cast bullets the top is 4.8. According to Winchester or Hodgdon that should get to 1070 fps. but that not always the case. And if you look at Hornady 10th for a lead 140 bullet you can go to 5.3 and should get 950 fps.

[45DUDE]

4.8 of 231 with a 158 hard cast lead is one of my favorite pistol loads for 40 years. Lyman is a good source for this. That's about 870 fps- and a +p load.- depends on what barrel you use. I am sure your lighter load is ok. Is that a heavy barrel? What twist are you using? Clark likes a 1 in 10'' twist. Standard is 18 3/4.'' I have one with 1 in 16'' that shoots really good with anything including a 200gr.

[rintinglen]

For action pistol I need to target 980FPS with my 127gr lead plain base hollow point (power factor). The bullet is essentially the MP 360640L at .358. Right now I'm up to 4.6 gr of W231 and averaging about 860 FPS (2 different chronos).

Looks like I may need to bump up to 4.8 grains of W231....is that getting a bit extreme?

Using a K frame S&W with Clark 6" barrel.

No, not really, Several sources, eg. Lee 2nd Edition, Speer 12th edition, Hodgdon on line data center, all list loads of 5.0-5,3 grains as +p max.
In the late 80's, early 90's, I personally shot hundreds of Winchester 125 JHP's as a factory duty load duplicate, all loaded with 5.1 grains of WW-231. Our issue round at the time was a Remington 125 +p. You have some room to move up to get where you need to be.

My own 360-640L casts at ~140 grains with the large HP pins installed. You might want to re-check your boolit weight.

[8shot]

No, not really, Several sources, eg. Lee 2nd Edition, Speer 12th edition, Hodgdon on line data center, all list loads of 5.0-5,3 grains as +p max.
In the late 80's, early 90's, I personally shot hundreds of Winchester 125 JHP's as a factory duty load duplicate, all loaded with 5.1 grains of WW-231. Our issue round at the time was a Remington 125 +p. You have some room to move up to get where you need to be.

Thanks...I finally settled in on 5.1...1001FPS average....and it's still 50 yard accurate.

BTW: MP advertises the bullet cast weight 135 gr when solid.

https://www.mp-molds.com/product/mp-360-640-light-pb-solid-4-cav/

Maybe you have this one (140 gr HP):

https://www.mp-molds.com/product/360-640-hollow-point-4-cavity-plain-base-mold/

My 360640 mold is stamped 360640L.

[rintinglen]

Mine is also marked with an L, but my boolits run 140-ish with the large HP. I have had mine for several years and it is one of my most used molds.

[Photog]

I use 5.0gr of W231 under 125gr cast for a top speed 38spl load. Its spicy compared to my sedate plinker loads, but nothing like a 357mag. In my 1866 carbine 20", I get 1450fps, and I have 4 different S&Ws and they vary a lot in speed, 2- model 10s and 2 model 15s. Quickload says 5 gr is at 12k psi, well under max. With a 158grain boolit, Quickload gives it 16k psi, which is getting closer into +P range, but still pretty safe with a Smith. Not advised, but not something that I would expect to destroy a gun at those pressures.