Working up a +P load

[drifterdon]

I have never loaded anything to +P pressures and was wondering if I should start at the lowest charge (non +P) then work up or if i can start at the Max charge (non +P) then work up into the +P values. My revolver is a M60-15 .357.
It doesn't make a lot of sense to me to start way at the bottom of the non +P values.
My Hornady 7th edition has the following. (HS-6)
38 spec. Non +P
Min Vel. Max Vel.
6.1 750 6.8 850

38 spec.+P
Min Vel. Max Vel.
7.1 900 7.4 950

New Starline cases, 140 XTP bullets, Fed 100 primers, HS-6 powder. I also have other powders such as 231, Power Pistol, bur of course the above values are shown for HS-6.

Just trying to get some input on starting point.

Any advice to offer?

Thanks

 

[Alk8944]

I have never loaded anything to +P pressures and was wondering if I should start at the lowest charge (non +P) then work up or if i can start at the Max charge (non +P) then work up into the +P values. My revolver is a M60-15 .357.
It doesn't make a lot of sense to me to start way at the bottom of the non +P values.
My Hornady 7th edition has the following. (HS-6)
38 spec. Non +P
Min Vel. Max Vel.
6.1 750 6.8 850

38 spec.+P
Min Vel. Max Vel.
7.1 900 7.4 950

New Starline cases, 140 XTP bullets, Fed 100 primers, HS-6 powder. I also have other powders such as 231, Power Pistol, bur of course the above values are shown for HS-6.

Just trying to get some input on starting point.

Any advice to offer?

Thanks

Well, DD,

There is going to be some argument about this, but your observation of starting with the starting load** for the +P range is valid. There is no point in starting with anything lower. As a matter of fact you could just start with the listed maximum since in most cases, assuming the published pressure for the load is correct, the pressure for the maximum load is still ca. 10% lower than the SAAMI MAP for .38+P of 20,000! The Hornady load will be very close to slightly higher than the SAAMI specification based on Hodgdon data.. Since you are shooting this in a .357 capable (35,000 PSI) revolver thhere will be absolutely no safety consideration with any .38 +P load, even if it gets slightly into the +P+ realm.

**Note: Hodgdon lists only a maximum load, no starting load, of 7.0 gr. @ 18,300 PSI. This is 92% of SAAMI MAP! I am speaking specifically about your situation and HS-6 since Hodgdon publishes data for the specified load where I do not believe Hornady does, and I have personal experience with HS-6.

My practice for many years has been to use manufacturers data as the primary source rather than a bullet maker's data.

The principal of "Working up a load while looking for pressure signs" is a concept based on high pressure rifle cartridges, not those (ANY!!) used in handguns. The first "pressure sign" often seen with a handgun is disassociated metal fragments that used to be your pistol raining down around your ears! The only time this happens is when you make a serious mistake and load a double charge, something you cannot anticipate by "working up"!

 

[drifterdon]

Thanks ALK8944,
I will probably start a little lower than the +P minimum just to see the differences in accuracy and feel. As far as maximum goes, Hodgdon, Lee, both give a max of 7.0 vs. Hornady's 7.4. Depending on velocities I record, I probably won't go as far as Hornady suggests.

 

[alwslate]

As Alk says you're loading +P 38 spl for use in a 357 magnum revolver
when maximum +P 38 loads in most manuals will be well under the
20,000 psi limit for 38+P. There's absolutely no reason why you can't
just start with the top charge weight listed for 38 +P and fire away in
your 357 magnum revolver.

 

[fredj338]

First, w/o a chrono, you are guessing. I agree, if working up a +p load, starting data seems a bit pointless. I start just below max & work up in 1/10gr increments, charting my vel gain. If the vel flattens or spikes, you are often at the max load for that powder/bullet combo.

 

[Nevada Ed]

In the .357..........
a full 100% +P load in a 38 case is not going to hurt a thing.

Try all powders that you have and see if you find one that hits
at POA. If not you can down load or go to the .357 case for a
higher energy loading, if you think you need one.

Since you are not shooting a 38 special, there is no problem.

If the 140gr does not work in your .357 you might try the 125gr
since it is the #1 stopper in that revolver in test over the years.

as a note;
with those powders in my 6" 686 and a 38 case with a 140 XTP bullet and cci primer
I reached 986 fps. My maximum load in the 38 case crossed my chrony at 1112 fps.
You only need 877 fps with a 140gr to get 240 ft/lbs of energy to out do the 135gr bullet.

 

[lebomm]

My guess is that you won't enjoy much shooting of full-power+ .357 ammo in your M60.
OTOH, if you bear that masochistic streak that so many of us handgunners do, stick with the 158-160gr JHPs and the faster powders.
Happy shooting !

Larry

 

[moxie]

The Hodgdon website doesn't have it anymore (used to), but the hard copy has the following note at the bottom of each data page:

"Loads listed are maximum, do not exceed, reduce by 10% to start."

 

[rwsmith]

lesser powder.....

Well, DD,

There is going to be some argument about this, but your observation of starting with the starting load** for the +P range is valid. There is no point in starting with anything lower. As a matter of fact you could just start with the listed maximum since in most cases, assuming the published pressure for the load is correct, the pressure for the maximum load is still ca. 10% lower than the SAAMI MAP for .38+P of 20,000! The Hornady load will be very close to slightly higher than the SAAMI specification based on Hodgdon data.. Since you are shooting this in a .357 capable (35,000 PSI) revolver thhere will be absolutely no safety consideration with any .38 +P load, even if it gets slightly into the +P+ realm.

**Note: Hodgdon lists only a maximum load, no starting load, of 7.0 gr. @ 18,300 PSI. This is 92% of SAAMI MAP! I am speaking specifically about your situation and HS-6 since Hodgdon publishes data for the specified load where I do not believe Hornady does, and I have personal experience with HS-6.

My practice for many years has been to use manufacturers data as the primary source rather than a bullet maker's data.

The principal of "Working up a load while looking for pressure signs" is a concept based on high pressure rifle cartridges, not those (ANY!!) used in handguns. The first "pressure sign" often seen with a handgun is disassociated metal fragments that used to be your pistol raining down around your ears! The only time this happens is when you make a serious mistake and load a double charge, something you cannot anticipate by "working up"!

Lesser powder = less explosion. Maybe it would just break the cylinder rather that blow the topstrap off.

BTW I did the same thing pretty much. I just picked the lightest charge in the .357 data and put it in .357 cases. I did this to use inside the house so it wouldn't blow our ears out. You can use any charge in a revolver below the max for its cartridge data as long as you reliably get the bullet out of the barrel. All the stuff about light charges detonating is in the past. I've gone WAY down on loads for experiments sake and never got close to sticking a bullet in the barrel and nothing ever detonated ether.

 

[colt_saa]

If you plan on loading to 38 +P or +P+ levels, just use 357 Mag brass instead.

This will prevent someone else from accidentally using what might be borderline 38 handloads in a weaker firearm.

ALL of my handloads intended for 357 Magnum firearms are loaded into 357 Magnum brass no matter how light the load.

 

[drifterdon]

Thanks all, I really appreciate the input.
I do have a chrony and luckily for me the club I belong to has the outdoor range just 5 miles away and no cost for me to shoot. So I can load up 10 of each level and head up to test them out, then come home and regroup before going on. If I do get into 357 territory, I will absolutely use 357 brass. And yes, full on 357 loads are no fun at all in a model 60.

 

[mikld]

You want +P loads, but how "hot" have you loaded your "non-+P" ammo? Perhaps a "hot" "normal" load will suit your needs. Anyway, in a +P rated gun there prolly won't be much or any trouble with starting at max. "standard pressure loadings", for an experienced reloader...

FWIW, I've never tried +P loads. If my .38 with "hot" standard loads ain't enough, I get out my .357 Magnum. Same with my .44s. If my 9mm is a bit small for a partiular job, I'll use my 45 ACP...

 

[drifterdon]

You want +P loads, but how "hot" have you loaded your "non-+P" ammo? Perhaps a "hot" "normal" load will suit your needs. Anyway, in a +P rated gun there prolly won't be much or any trouble with starting at max. "standard pressure loadings", for an experienced reloader...

FWIW, I've never tried +P loads. If my .38 with "hot" standard loads ain't enough, I get out my .357 Magnum. Same with my .44s. If my 9mm is a bit small for a partiular job, I'll use my 45 ACP...

What you say makes sense but I prefer to just carry one gun with me.

 

[Forrest r]

I'd ditch the hs-6 and the light 140gr bullet. 6.3gr of power pistol and a 158gr lead swc hp will get you 1000fps with your snob nosed revolver.

In 2012 brian peace did an article on 38spl p+ loads and used a ruger 1.875" bbl. He got 1000fps with the buffalo bore fbi 38spl p+ load in that ruger. And he got 1004fps in that same ruger using a 158gr rimrock swc hp that was gas checked with 6.3gr of power pistol. He also did a load using the lyman 173gr swc "keith" bullet using 4.9gr of power pistol and got 946fps out of that 1.875" bbl'd ruger lcr with that load.

Every load he tested was within saami 38spl p+ pressure limits.

HS-6 does better with mag primers but it won't get you to the promised land. Go with a 158gr lead hp and 6.3gr of power pistol. It duplicates the hot buffalo bore load.

 

[moxie]

Any idea what kind of setup Brian Pearce uses to test pressures?

 

[moxie]

Any idea at all?

 

[Bkreutz]

Any idea at all?

I would imagine something along these lines, https://www.google.com/search?q=pistol+barrel+pressure+test+instrument&tbm=isch&imgil=MTLXxtS1s7qA-M%253A%253BYQCVVkigq2MWlM%253Bhttp%25253A%25252F%25252Fwww.ketmer.com%25252Fhsp%25252Ftesting%25252Findex.htm&source=iu&pf=m&fir=MTLXxtS1s7qA-M%253A%252CYQCVVkigq2MWlM%252C_&usg=__hpm1qMPwt6chYRC6bSsd-UIwcoA%3D&biw=1920&bih=946&ved=0ahUKEwj61saWpPnLAhVEsIMKHVvPBQoQyjcILA&ei=-p4EV_rxHcTgjgTbnpdQ#imgrc=df-nzQiH2xUAoM%3A

The older stuff is a lot clunkier. (is that a word?)

 

[Forrest r]

Any idea at all?

The article didn't say. I know he's used strain gauges in the past.

 

[moxie]

Thanks!

Since pressure testing, especially for handguns, is rather rare and pricey outside of the full-fledged ballistics lab, I'm just curious as to how he arrived at the statement that all the loads were within SAAMI pressure specs. Pressure testing for the hobbyist, even gunwriters, hasn't yet become common like chronos. Probably be a while until we see a reliable, affordable rig for the average reloader. And since it is rather rare, if Mr. Pearce is having good results with a given setup, you would think he'd share that in the article.

 

[mikld]

What you say makes sense but I prefer to just carry one gun with me.

??? I only carry one gun (I know some carry a "back up" even when carrying concealed). If my situation/quarry is best suited by a Magnum cartridge, I'll use a Magnum gun. If I'm hunting beer cans standard loads suffice and can be used in the Magnum gun too!