There are several questions / topics that have come to mind for me as I have followed this topic. In no particular order, here are some of them--

1. We generally assume "progress"--as in, 'pressure tests are now more precise;' or metallurgical advances provide better steel / alloy;' or 'powder batches are more consistent.'

2. Guidelines are developed strictly from the professional criteria for a given subject, with no "political considerations."

And, of course, we can list all sorts of subsets of these hypotheses....

What I think we often miss is that in the last 40 years, there has not only been tremendous 'advancement' in technological processes (think CNC machining, as the basic example), there has also been development, advancement and widespread dispersion of other "subjects:" the academic subject of "business," and the development of the "MBA-type" for business management.

When I did my undergraduate work forty years ago, friends who went on to get MBAs did so at limited numbers of schools--Harvard, Chicago, Wharton. They had strong backgrounds in economics, not undergraduate business degrees. Other than the qualitative aspect of their education, their quantitative expertise was undone by 1983--by the time VisiCalc was widespread, and anyone with a PC and some learning could do the same work my friends had sweat through to do on primitive computers or limited calculators.

Rather than segue any further, I think was we see here is an epic shift in the paradigms that effect a niche subject. In short, "business decisions" and "politics" are now influencing the "hard data" and discrete knowledge we have about (internal) ballistics.

Given the Internet, a CAD file for a firearm frame can be shipped to China in a matter of seconds--along with a separate file for the metallurgical specifications, etc. But, what business decisions will enter into the characteristics of the final product.

Enough, I digress too much for this topic.

Jim H.

I would think, from a product liability point of view, the possibility of finding and shooting older ammunition would prevent lessening the design limits on new production guns.

I know I have some 40 year old factory .41 Magnums, so the same possibility exists for .38 Special and/or .357 Magnum.

Let me through some more charts in the fire

It seems that changes driven by legal concerns or expectations of lower quality of the new production guns should apply equally to all powders and all bullet styles. Not sure that’s the case.

The chart below compares recommended powder ranges for 2 types of jacketed bullets – 125 gr. and 158 gr. Speer #8 data is taken from Paul’s web site; Hodgdon and Alliant – from their web sites; Speer #13 and Lyman 3rd edition from their published reloading manuals.



Two observations from this chart.

First, while Speer #8 tends to be on the higher end of the range, modern manuals are not always more conservative.

Second, for almost all powders recommended ranges did not change too much over time. With one notable exception, maximum recommended charges are within less than 10% of each other. The exception of course is SR4756 where Speer #8 recommended TWICE higher charge then Hodgdon today. I was unable to find any other modern SR4756 data for these bullets in 357 magnum. If anyone has it, please let me know - I’d be interested to add it to the chart for comparison.

Seeing is believing!

Mike

quote:

First, while Speer #8 tends to be on the higher end of the range, modern manuals are not always more conservative.

Second, for almost all powders recommended ranges did not change too much over time. With one notable exception, maximum recommended charges are within less than 10% of each other. The exception of course is SR4756 where Speer #8 recommended TWICE higher charge then Hodgdon today. I was unable to find any other modern SR4756 data for these bullets in 357 magnum. If anyone has it, please let me know - I’d be interested to add it to the chart for comparison.

Seeing is believing!

Mike

That’s rather hard to ignore in regards to SR4756.

Dennis,

It is also worth considering that max Hodgdon load is rated at 29.9 - 30.6 kPSI which is lower then max pressures for other powders in the same manual.

In fact given very significant differences between pressure ratings of their max loads (9,000 - 43,000 CUP) I am not sure how exaclty Hodgdon selects their recommended ranges.

Well, here's ONE EXPLANATION for the Speer #8 / 4756 data:

"...In the mid to late '70s the standard law enforcement sidearm in the US was the 357 wheelgun. Mostly S&W, some Colts. The "Dirty Harry" series had made the work "Magnum" a bad name, and cops didn't want to admit they were shooting "Evil Magnums" on the witness stand.

"So in conjunction with major ammo houses, a conspiracy developed in order to allow cops to lie in court.

"MOST 38+P+ ammo was designed to be shot out of 357 guns, and came so close to 357 performance as to be basically mis-named and slightly shortened 357Mag ammo.

"Cops that shot it out of 38snub backup guns shot them loose in short order and sometimes experienced k'booms...."

posted by Jim March at THR / ...revolvers, Jan 18th, 2008. Here's the link to his entire post.

Intuitively, his explanation makes sense to me. Others reactions?

Jim H.

quote:

jhf:"MOST 38+P+ ammo was designed to be shot out of 357 guns, and came so close to 357 performance as to be basically mis-named and slightly shortened 357Mag ammo.

The problem with +p+ is there is no industry standard. This is a rather inconvenient truth.

Jim,

I think this makes a lot of sense. In fact it's possible that for the same reason performance of modern 9mm +P+ is so close to 357SIG... "Evil 9mm"?

Mike

quote:

The problem with +p+ is there is no industry standard. This is a rather inconvenient truth.

Well, maybe this is actually rather "convenient truth". Since no gun is rated for 38 spl +P+, cops would HAVE to shoot this ammo from 357 mag rated revolvers. Safe to the shooter and good in court...

quote:

Safe to the shooter and good in court...

It's a sad state of affairs indeed when we have to develop ways for our good guys to find a way to lie in a court when protecting us.

Truth is always inconvenient when we have another agenda.

quote:

It is also worth considering that max Hodgdon load is rated at 29.9 - 30.6 kPSI which is lower then max pressures for other powders in the same manual.

This is what has interested me most about SR4756. It seems almost singled out so as not to develop the pressure that others use as a maximum. One thing I know is the Hodgdon data "ain't" even close to what real world velocities are.

I took the data Hodgdon had for 357mag, SR4756 and 158gr LSWC and went to the range. With the load they said would develop 27.4kpsi and give a nice velocity of 1200+fps I only got 980fps.

Now I ask you this, if they got 1200+fps and 27.4kpsi what pressure did I actually develop to get only 980fps.

It would stand to reason that it couldn't be the same because as has been stated earlier, we get nothing for free, it would seem to me it was much less.

If it was linear it would be simple. 1200/27.4 = 980/? With the calculation I get 22376.67. Now what powder charge will get me the 1200? Again if it was linear it would be simple too. 980/6.5=1200/? With that calculation I get almost 8 grains. of powder. I can tell you I used 9.0 grains and got 1260 fps. I would think then that the pressure to get me 1260 would actually be slightly above their posted pressure of 27.4 kpsi.


With the Hodgdon data I find it odd that the pressures stop for SR4756 where they do. The posted velocity is near their other powders but their pressure is nowhere near them.
Case in point, SR4756, 158gr XTP, 1100+fps, 29.9kpsi. The SAAMI maximum is 35kpsi. Why did they stop there? I think it is because they got the velocity close to the other powders.

Comments?

quote:

rozenbem;Well, maybe this is actually rather "convenient truth". Since no gun is rated for 38 spl +P+, cops would HAVE to shoot this ammo from 357 mag rated revolvers. Safe to the shooter and good in court...

But there is a 38 Special revolver rated for +P+. The M640 with serial number prefix CEN came from the factory with “TESTED FOR+P+” wording in the frame window. Yes I own an example.

Since there was and is not an industry standard for +P+ the wording was deleted on subsequent production samples.

quote:

With the load they said would develop 27.4kpsi and give a nice velocity of 1200+fps I only got 980fps.

Well, since that is the new Hodgdon data, Skip, they got that out of a 10" pressure barrel--not from a conventional revolver.

About 4756 recipes--I find it interesting that the Speer 14 (newest; just out six months) lists precisely ONE 4756 load in the whole 38+P / 357 sections. That one load is a standard-pressure recipe for 5.6 gr. max under a 158 gr lead bullet--any one of their 3 158s.

They do have a "Short Barrel" section, and it has data expanded from the PDFs that were available earler for the GDSB 110 / 135 / 147 -gr bullets in both 38 and 357--

I can live with new data, as long as it has a consistent test procedure. But, to use it, I have to do my own formulations--i.e., who wants a 29.5K 357 load?

That gets them off the hook, I guess.

rezenbem: I've been gathering all the 4756 recipes I can find. Send me an e-mail and I will sent on a comma-delimited (or whatever) export to you. I do think you may have all the current ones, save for one or two I scrounged out of forums that appear to be legit.

Jim H.

All I know is I shot some 358429s today with 9.0 gr of SR 4756, but the bullet was loaded short for a M28 type "short" cylinder. Then I shot a couple of 125 gr with 14.0 gr of SR 4756. All of it in some old Speer brass (does Speer still make brass?).

I used 2004 vintage IMR SR4756 and didn't experience any surprises. But then, why should I expect any surprises with loads I've been using since 1972?

Dennis, do you have any idea why I should expect surprises? I was using a fairly late model 1989 Dan Wesson M715 with a recessed cylinder. That may be new enough to only qualify for wimp loads, even though it weighs 45 ounces.

Wow, a lot of good postings while I was out walking my dog!

quote:

Skip:
It's a sad state of affairs indeed when we have to develop ways for our good guys to find a way to lie in a court when protecting us.

Truth is always inconvenient when we have another agenda.

Very true, Skip! Can’t agree more with you.

quote:

Skip:
Now I ask you this, if they got 1200+fps and 27.4kpsi what pressure did I actually develop to get only 980fps.

It would stand to reason that it couldn't be the same because as has been stated earlier, we get nothing for free, it would seem to me it was much less.

quote:

Jim:
Well, since that is the new Hodgdon data, Skip, they got that out of a 10" pressure barrel--not from a conventional revolver.

I don’t know for sure but I think the answer is that Hodgdon got same max pressure in their 10” test barrel as Skip in his revolver despite significant difference in velocities. Where did the free lunch come from?

I hate to annoy everyone with more charts but need one to explain my point. So, let’s look at a pressure chart. This one is taken from http://www.swproducts.biz/PressureTrace.php; Paul posted similar chart before from one of the reloading articles.

In this example pressure reaches it’s maximum after 0.4 ms and drops slowly after that. Regardless of the barrel length, maximum pressure is set at that time point. As bullet continues it’s run through the barrel, residual pressure continues to accelerate it without any change of maximum pressure.

We had this discussion before and the question was asked – to what extent? My thinking is that since pressure is not constant, velocity is roughly proportional to area under the curve. In other words velocity of a bullet that exited barrel after 1 ms (appr. 10” barrel) will be twice higher compared to a bullet that exited after 0.5 ms (appr. 2” barrel). Max pressure would be same in both cases.

quote:

Dennis:
But there is a 38 Special revolver rated for +P+. The M640 with serial number prefix CEN came from the factory with “TESTED FOR+P+” wording in the frame window. Yes I own an example.

Since there was and is not an industry standard for +P+ the wording was deleted on subsequent production samples.

Okay. This is a new information for me.

quote:

Jim:
rezenbem: I've been gathering all the 4756 recipes I can find. Send me an e-mail and I will sent on a comma-delimited (or whatever) export to you. I do think you may have all the current ones, save for one or two I scrounged out of forums that appear to be legit.

Perfect, Jim, will send email in a minute. BTW, it’s okay to call me Mike.

On the way back from my walk, I stopped by G.I. Joe’s and got a can of SR4756. Time to hit the range with some loads!

Mike

P.S. Jim, can't find your email address. Please email me at mike.rosenberg@comcast.net. Thanks. --M.