Hornady Reloading manual (7th)--way too conservative?

[HankB]

The original poster questioned .357 loads.

SAAMI has in past years reduced the maximum allowable pressure in .357 loads from, IIRC, ~42,000 CUP down to 35,000 PSI.

Some of this IS new technology - piezo transducers vs. copper crushers, hence the move to from CUP to PSI. Although there's no exact formula for converting from one measurement to the other, CUP generally tends to be numerically lower than PSI with the same load. So the 42,000 CUP load may have actually measured 45,000 PSI (just a guess) if checked with modern equipment.

So . . . why the lower PSI number? Lawyers? Maybe . . . some of the loads in, for example, the #8 Speer manual do appear excessive.

But remember, the .357 was originally an N-Frame S&W proposition; the K-frame .357s (according to some) didn't hold up well to a steady diet of full power magnum ammo, and as for J-frames and SP-101s . . . they would have a short life on full power mag ammo.

So to accomodate manufacturers that were putting out weaker guns, SAAMI reduced the maximum pressure allowed.

So today's loads generally are lower than yesterday's - to reflect the new, reduced SAAMI limits.

I've read - but haven't been able to confirm - that SAAMI does allow the old ~42,000 CUP limit on "SAAMI-spec" ammo, which may be why companies like Buffalo Bore seem to get more "oomph" out of their ammo than other manufacturers.

(If anyone actually working in the industry can confirm or correct the above, please do so.)

[SL1]

Hank,

My old Speer #10 Manual says the SAAMI spec was 46,000 CUP. Others seem to say 45,000 CUP, so I'm not sure the Speer manual doesn't have a typo.

But, it is obviously true that the actual pressures have been lowered, because there is less powder in the new max charges. The "story" I always read is that the new lighter framed guns are the reason that SAAMI lowered the standard. If that is the truth, then it is unethical. Not a surprise, because SAAMI is a group of industry folks, not an "independent consumer safety testing agency."

I say "unethical" because it is downgrading the performance of propely designed guns to accommodate improperly designed guns. When a standard is set, as it was at 45,000 CUP, then guns should have been designed to handle it. That design process for the guns is empirical (based on laboratory testing and experience), not a high - tech computer simulation that assumes we know the "real" pressure and designes only to accommodate it.

Some early light framed 357 magnums were marketed with warnings that continuous use of full-power loads would shorten gun life. The guns' "life shortneing" was usually due to split barrels at the forcing cone or damaged cylinder closure or lock-up hardware that was not likely to shorten the SHOOTER's life.

So, I think it would have been more ethical to keep the original pressure standard's actual pressure levels when the new standard was developed. If the industry wanted to set a lower standard for continuous use in light framed revolvers, I think it should have created a new ".357 Magnum lite" standard. Then, manufacturers could have made sure they did not get cycle fatigue in cartridge chambers at that lower level of pressure and limited their light guns to the new "Lite" standard. The SAAMI "+P" and "+P+" standards actually do that for some cartridges, already, so why didn't they do s similar thing for the 357 magnum?

This would also have prevented a lot of safety problems with handloaders trying to get back to the performance that they thought they were getting when they bought 357 magnum guns. When a "safey" standard is widely perceived to be too conservative, it tends to make most people disregard it and try to find a safety-performance trade-off that suits them personally. A good example is the 55 mph speed limit. We can easily see the variety of speeds that people really do. But, those drivers have much more feed-back on how their driving is affecting their safety than we handloaders have when we exceed SAAMI specs with our loads.

SL1

[TargetTerror]

It sounds like they should have tiered-level loading data for the 357 magnum like they do for 45-70.

[Jim Thompson]

I guess there's people that would load maximum loads in an old firearm that will not take the pressure. There are gonna get a law suit out of the deal even if they warn you not to do it. There are those among us that do not need to be reloading. I never reload old guns and do look at old manuals and sometimes split the difference.

[DMZX]

I find that I rarely load to maximum. I always seek the point on the curve where I can achieve good velocity, at below peak pressure. Here is an example (from the Hodgdon website):

125 gr XTP will give 1425 fps w/6.8 gr of Titegroup (36,500 CUP)

One can gain an additional 72 fps by loading to max - 7.5 gr Titegroup, but the pressure goes up by 4,700 CUP, to get there.

or

158 Gr XTP will give 1,418fps w/15.0 gr of H110 (28,600 CUP)

Or you can achieve 1,591fps by taking the pressure to 40,700 CUP with 16.7gr of H110.

That additional 12,100 CUP of pressure will yield 173fps of velocity. It also results in quite a bit more felt recoil.

I have not done this (maybe someone else has?), but I think one could develop pressure vs velocity curves, with a spreadsheet, to find an optimum point for any given bullet/powder combination in any caliber.

[WESHOOT2]

IF I were in charge of SAAMI I would, in your specific stated case, keep the demonstrated safe choice in print.


There is still the chance for many chamberings to find old homes. Danger.

Since most folks miss this part, I'll remind them here that "Start low work up slow" means exactly that.
Then there is less danger.

(I never joined SAAMI; insurance was very expensive.)

[Peter M. Eick]

Thanks for the answer. To me that was the crux of the whole SAAMI question/problem.

Start low, work up carefully, have a plan for the load is now my basic motto.

Gosh, I think I picked up those rules from you.