Developing Load Data

[fractal7]

So two questions, one more broad and then a more specific.

So first, how do you generally come up with load data for specific combinations of components that aren't specifically listed in reloading manuals.

Second, I am currently trying to come up with some .38 special / 357 magnum loads and the components I currently have are:

Green dot powder
Hornady 125 gr HP/XTP bullets
CCI 550 primers

Does anyone have any suggestions for loads or perhaps where to look for data for those components?

Sorry for the hodgepodge of components, I've basically been scrounging together what I can find because of the current supply issues.

Thanks

 

[bensdad]

Find a load (with your powder) that uses a bullet of the SAME weight and similar profile. Start low.

ETA: I checked two manuals and found no loads for Green Dot with that bullet weight and caliber. Wait for someone smarter than me to come along and help (unless you have already found a published load). If Green Dot isn't mentioned in Speer and Nosler, there might be a reason.

 

[Jim Watson]

You gotta shop around for loads like that.

Speer #9 (1974) shows their 125 gr JHP and 4.5 gr Green Dot in .38 Special MAXIMUM.
I would not hesitate to load that in Special brass for use in a Magnum gun. In a small frame gun, go back to the starting load of 4.3 grains, especially since you have a different brand of bullet. Maybe clear back to 4.1, the traditional 10% reduction.

Strangely, Speer #9 does not show .357 Magnum with Green Dot but #10 does.
125 gr JHP and 8.5 gr Green Dot in .357 MAXIMUM. They start at 8.0 but for current components and Hornady bullet I would go down at least 10% to 7.7.

 

[freakshow10mm]

Given the unknown experience of the OP, my suggestion is to buy one of the powders listed in the provided data that will get you close to your velocity goals and use that before you venture off in uncharted water making SWAGs about things like this.

 

[Walkalong]

Green Dot will work for .38 Spl, and for light loads in .357.

I recently tried some in .357 cases with a Berrys 125 Gr TrFP plated bullet.

WSP primer, Berrys 125 Gr TrFP, 4.1 Grs Green Dot, Light taper crimp, CCI brass trimmed to 1.280, 1.550 O.A.L. - 67 Degrees.

6" Trooper Mk III

Hi-826
Lo-764
Avg-799
ES-62
SD-23

I picked 4.1 to start. There were no pressure signs. It could go up a grain or two. I would drop it .2 grains (3.9) to start in .38 Spl brass with 125 Gr plated or jacketed bullets.

Good luck. Be careful, have fun.

 

[rcmodel]

1996 Alliant load manual lists Green Dot / 125 JHP as follows.

.38 Spl = 4.3 - 985 FPS - 15,900 PSI.

.38 Spl +P = 4.6 - 1,015 FPS - 17,500 PSI.

.357 Mag = 7.3 - 1,415 FPS- 33,600 PSI.

As always, reduce 10% for a starting load and work up, and do not exceed the loads listed.

Do Not reduce more then 10%.

rc

 

[Walkalong]

Well that settles it.

 

[rcmodel]

I should also have said
Do Not reduce more then 10%.

rc

 

[Jim Watson]

Heck, they already are reduced.

Do you have an idea why Alliant stopped at 15,900 psi when the 1981 standard was 18,900 CUP and the 1994 SAAMI MAP was 17,000 psi?
Likewise Alliant running out of steam at 17,500 +P when it was 22,400 CUP in 1981 and 18,500 psi in 1994.

(Yes, I know CUP and piezo psi are not directly comparable, which actually makes it even more confusing to me because a piezoelectric transducer will normally give a higher number than a crusher gauge for the same load.)

 

[ForneyRider]

Beg and plead to the component manufacturer to give you one.

For 36gr Varmint Grenade and Reloder 10x, I plan on using a similar length bullet, the VG's are longer than the 40gr Sierra HP I have so I need to find another similar length bullet and data with 10x powder, then go from there.

I have Lyman 49th, but no 10x powder loads for .223. But I can get OAL from this book.

Barnes info didn't have 10x data, on 36gr but did on 50gr VG. Alliant data didn't cover 36gr VG. Nosler doesn't have an equivalent weight bullet, so my Nosler book won't help. Lee book only has 35gr generic bullet for .223 and no 10x loads.

I will make 2-3 loads, about 5-10 each, all below what my guess is max and shoot until I get the fps(trajectory reasons) and accuracy I am looking for.

If I don't feel comfortable, I will use AA2230 or another powder in the Lyman book.

 

[rcmodel]

Do you have an idea why Alliant stopped at 15,900 psi when the 1981 standard was 18,900

I have to assume they ran into pressure spike problems with Green Dot once past where they stopped.

But I'm just guessing.

On the otherhand, they always were pretty conservative compared to some other sources.

rc

 

[ants]

What the technicians told me

At the Shot Show several years ago, lab techs for several manufacturers explained some of the industry's standard practices.

After shooting a string, mean and standard deviation are calculated from the data. After all the strings are shot and statistics calculated, max load is the one whose MAP plus two standard deviations does not exceed maximum pressure (SAAMI or whatever standard is adopted). So a large standard deviation will keep the max load to a very low pressure. A small SD will yield a MAP very close to the standard.

This also explains why max load may increase or decrease compared to previous editions of the same manual. As you very well know, SD can vary widely from sample to sample. Although Internet lore says that lawyers lower the data, the technicians point out that newer methodologies often produce different data than old methods. Different data can yield grossly different standard deviation statistics, even if average pressure remains the same.

 

[fractal7]

Double check

Ok so here is where I am now with a few more questions:

I found some HS-6 powder and the Speer reloading manual has a recipe calling for:

Start charge
10.0 grs HS-6

Muzzle Velocity
1009 ft/s

*Magnum Primer (CCI 550)

125 gr Speer Gold Dot Hollow Point

COAL tested 1.580"

So now my questions are

1) I have the correct powder and primer combination from the manual, is there anything I should know about brass (also is it ok to reload the nickel plated cases from factory gold dot ammo, if not I can just use regular brass cases)?

2) If I have 125 grain .357" Hornady HP/XTP hollow points, can I still substitute the same formula?

3) The bullets do have a cannelure, should I crimp? And if so, how much crimp exactly is correct?

Thanks again.