Reloaders Reference Question

[jim4065]

I'm trying to start reloading some 380's on the new press, but having problems finding load data. I have both Russian "Unique" and Alliant Bullseye. Most of my manuals are old - but I put a lot of trust in "Reloaders Reference" which was downloaded from here (or Cast Boolits).

Here's the problem: with either "real" Unique or Bullseye, the heavier the bullet, the more powder they allow. Say what? If I'm allowed 3.3 grains of Bullseye with a 100 grain bullet, why only 3.0 grains with a 90 grain bullet? I wouldn't think it's case capacity - Bullseye sure doesn't bulk much.

[versifier]

Wilgen has added current loading data from as many sources as he can find. I think he's a very trustworthy source. It never hurts to have a current manual or two around though. I like books and will reach for one quicker than I'd go upstairs and look up and print loading data off my computer. The book works much better when the power goes out, too, a regular problem here.

But to answer your question, it takes more powder to move the heavier bullet at the same velocity. How much the pressure varies is different for each powder, but it's the pressure level that determines a MAX load, not the velocity.

With a surp powder, often the only guide is some cryptic line like "Use data for powder XYZ #007". Even with a chrono (and you really ought to have one if you are running surp powders) I don't like to approach the listed max for the "similar" commercial powder, especially not if I was seeing decent accuracy in the lighter loads. And you have to retest every different lot of surp powder you get, because unlike commercial " cannister powder", the surp "non-cannister" will have much wider burning rate tolerances from batch to batch. Factories get it in huge batches and test each lot, adjusting the charge levels so that they get the same velocity for each run of ammo they turn out. It is better to buy surp powder in larger amounts when you can (30-50lbs) and stock up on the same lot # so you can use the same data, instead of buying small amounts of different lots and having to go through all the tests again every time. If stored correctly, powder lasts many years without deteriorating.

[atr]

versifier is right on about pressure being the factor which determines the load charge...

I used to reload for the .380 and you have to remember that the pressure also has to work the action. Test a few loads to make sure your reloads work the action before you go into "mass" production. I will try to find some additional load data for you...
atr

[jim4065]

OK - I agree with all that, but it doesn't address the issue - which concerns Alliant more than Reloaders Reference.

The listing for cartridge and powder shows 380ACP and (American) Unique with four loads:
88 gr 4 gr Unique 920 fps
90 gr 4 gr Unique 940 fps
95 gr 4.2 gr Unique 910 fps
100 gr 4.3 gr Unique 1005 fps

If I can run 4.3 gr behind a 100 gr bullet, why can't I run 4.3 grains behind all the others? The pressure should be lower for the lighter weight bullets with the same powder. Notice that all of these loads are with jacketed - so jacketed versus cast is not an issue here.

[versifier]

.380ACP Max loads from the Sierra Manual:
90gr bullet 4.6gr Unique
95gr bullet 4.0gr Unique
115gr bullet 3.5gr Unique

.380ACP Max loads from the Lee Manual:
88gr bullet 4.0gr Unique
90gr bullet 4.0gr Unique
95gr bullet 4.2gr Unique
100gr bullet 4.3gr Unique

Despite it's age, I checked the 1981 edition of NRA's Handloading; their data is from Sierra.

You're right. It doesn't make sense to me either. Lee gets its data from powder and bullet makers and puts it all together, that's clearly the same source. My Lyman Manual is not here so I can't refer to it today. Hopefully others will chime in with data from Hornady, Lyman, Speer, etc and we can get to the bottom of it. How about it, guys?

It's a smart man who stops to find out when something doesn't look right. People do make mistakes, and some of them work in data entry. That's why you need three current references when evaluating a new load. When there is a question, two sources should be in pretty close agreement. (FWIW, I have never found an error in any Sierra Manual in the last 35 years, but I won't bet my life on one set of data when others are available.) Let's see what happens when we have more data.

[atr]

for Jacketed bullets my Sierra manual gives
90 gr bullet 3.2 gr Unique min.....4.6 gr Unique max
115 gr bullet 2.7 gr Unique min.....3.5 gr Unique max

for Cast boolits my Lyman manual give
92 gr boolit 3.1 min to 3.7 max Unique
121 gr boolit 2.2 min to 2.8 max Unique
NOTE THAT THE CAST BOOLITS HAVE A SMALLER COEFFICIENT OF FRICTION THAN THE JACKETED ONES SO IT MAKES SENSE THAT A SMALLER CHARGE COULD BE USED

some variables which might affect the tables when comparing values would be the type of primer used (magnum vs standard)

your question "why can't I run 4.3 grains behind all the others?" is a good one and one I can't actually answer. However I suspect the answer might lie in how the pressure curve from a given charge is generated. Even though common sense would seem to say that you could use 4.3 grains in all the others, it may not be possible due to how the pressure curve is generated.....

[jim4065]

The Alliant Powder website shows the following "maximum" load:

90 gr Gold Dot HP 4.6 grains of Unique.

Makes me wonder if the pressure generated by Unique is lower in the "new - clean burning" Unique? It would be interesting to know the date of the tests behind these data - perhaps the manufacturers are making a product which constantly "improves" i. e. generates less pressure to give a constant weight bullet a given velocity. Sure be nice to see some "raw data" before it's massaged by the "experts" (most of whom seem averse to proof-reading).

[atr]

the Sierra manual I quoted from is copy writed 1971......
Ive used this manual for loading charges for .38 and .357mag with current manuf. Unique without any problems.

if the Alliant Powder website is showing 4.6 gr of Unique max with a 90 gr bullet THEN, that charge seems to be verified by the Data from my 1971 Sierra Manual (90 gr bullet /
4.6 gr Unique max)