Loading Data Changes

[stormytexas]

Okay, I admit it. I am now a geezer. 30 years ago, I was an avid reloader. Then, career and family interrupted that and most of the loading stuff got put up and was only used for long loading runs of 9mm and .223 and a little .45 acp. Earlier this year, I pulled all the stuff together and started loading up again. I have numerous older loading manuals and I have a couple of new ones. I have noticed that the loads have changed but most of the powders have not. For example, the max load in the old Sierra book on one bullet was 59.1 grains of WW630. Now in the newer book, it is somewhat less than that. I have great loads worked up for cartridges, but the problem is, most of them exceed what is, in today's manuals, the maximum load. Naturally, if I were to use a newer powder like Power Pistol, I would go with contemporary loading data, but what about these old long time powders that have been around forever?

My questions are these: Is WW630 the exact same powder today that it was 25 years ago? Have the darned lawyers forced loads down for liability reasons? Am I safe to use the older loads that were worked up (with no signs of pressure problems whatsoever) or should I work up new loads based on current data? One of my favorite powders was IMR 4064...is that still the same formula?

I think I need some good advice here. I am not averse to starting over at square one with loads, but that sure seems like a waste of time if the only reason I am doing is because someone had a problem with a firearm that wasn't properly maintained or was too old to shoot with modern powders, i.e. liability reasons.

 

[stevelyn]

A lot of the changes has to do with pressure measuring equipment becoming more accurate and giving truer readings.

 

[taliv]

welcome to THR

honestly, i doubt anyone on this site can speak authoritatively about the exact chemical changes to powders over the past 30 years. and if they were in a position to know, then they'd be taking on quite a lot of liability telling you to load hotter than max.

it would be interesting to know and it's a good question, but it's also a pretty trivial amount of effort for you to load a few cartridges with lighter charges and make sure you're not seeing pressure. (keeping in mind that it's cooler outside now than it will be next july...)

eta: i'm not trying to squash the discussion at all, just realize you'll get an awful lot of guessing and speculation which is just that.

 

[MachIVshooter]

A lot of the changes has to do with pressure measuring equipment becoming more accurate and giving truer readings.

I suspect this is the biggest reason. It's not like metals have become weaker.

Personally, when looking for maximum performance, I go through several books, find the hottest charge, and start just a little below that. I'll usually end up at or just over max published data. I use Winchester primers when working up loads; They seem to display pressure signs sooner than the plated primers from Remington, Federal or CCI.

 

[rcmodel]

Is WW630 the exact same powder today that it was 25 years ago?

Yes, and No.
WW-630 powder has been discontinued for at least 20 years!

So if you have some, it is the exact same powder, cause it was made at least that long ago.

rc

 

[Red October]

I have noticed the same issue. About 20 years ago, I shot .41 Magnum a lot. A medium load in the Speer book for a 210gr JWC was 17.6 grains of 2400. Now this is listed as a hot load.
Maybe 2400 has changed (since it used to be Hercules, and has changed hands twice, I think).
Maybe it's the lawyers.
I'd hate to say, not knowing.

 

[rcmodel]

In the intervening years, SAAMI has lowered the pressure spec for all the Magnum handgun calibers, and added the +P designation and lowered the standard pressure on others.

Pressure test methods have also changed from Copper Units of Pressure (CUP) to electronic transducer pressure measurement (PSI).

That right there allowed previously unnoticed very brief pressure spikes to be seen & measured that were previously unmeasurable & unknown using the copper crusher test method.

Of course, there may be some lawyering going on too, but it is not the driving force behind most of the noticeable changes.

rc

 

[Dr T]

The liability aspect is also there. The pet load that I use for my 30-06 with 180 gr bullet was in a Speer manual that I got when I was in graduate school back in the mid-70's. It is 2 gr. heavier than the current load with the same powder. (I have been told that the load I use was also the Lake City Arsenal match load back in the day).

However, I see no overt signs of pressure. Also it is used in Ruger No. 1 which has an extremely strong action. And, I worked up to it carefully.

I think that we are seeing lower charge weights in part because of the wide range of action types (and strengths) that must be accommodated. For example, my Remington 788 in 6 mm is very accurate--but the action is much weaker than a Model 700. I learned this the hard way working through some of Ken Water's Pet Loads. (If he said MAXIMUM, I would want to stay a long way away from that much powder).

 

[Art Eatman]

Going back to 1950 when I started reloading, I've seen a common piece of advice: Even with the same powder, when using a different Lot #, back off your previous maximum load and work back up.

I've never had any pressure-sign problem, but I tend to re-start at about 96% of my previous maximum load. I'll load three rounds at 96%, three at 98% and in the past have wound up with the same old load. But, "Checking is cheap."

 

[Still Shooting]

Times Change...

Similarly to OP, I had a 23 year hiatus from reloading. When I got seriously back into it, I discovered that all of my "pet loads" needed revision. The load my .270 liked best is now over maximum in the tables, but it had never showed signs of overpressure in the past. My favorite load in the .257 Roberts from back in the mid-80's was sub-moa; the same components and powder loaded a year ago was in excess of 2 moa. On that one, the brass and bullets were from the original time period.

I guess I have concluded that over the years, what with different chemical suppliers, production equipment, etc, the powder specs and performance have probably "drifted" from what they were. I also suspect a lawyerly presence may have injected conservative bias in max. load numbers. But with 11 calibers I'm loading for my rifles, working up new loads has NOT been a trivial exercise. I have even shifted powders on some loads in order to get the same kinds of groups I am used to. It has forced a lot of "ladder" loading, caused me to buy a bunch of new or different powders, and meant I had to spend a lot of time on the range for two years now...

 

[Jim Watson]

"That right there allowed previously unnoticed very brief pressure spikes to be seen & measured that were previously unmeasurable & unknown using the copper crusher test method."

I agree that is the progression of chamber pressure measurment equipment and technique.
My question is: Those "very brief pressure spikes" had not been blowing up guns for some good number of decades before they were measured, so why did the loads have to be reduced?
OK, I know the answer, too. The specification was a number, the crusher or transducer calibrated off of reference ammunition. We are sure not going to change the number, so the ammo companies and reloading data publishers are going to have to change the loads.