Were older shotgun primers a lot colder?

[smleno1mkIII]

Is that how they got away with some of the ridiculous charges in older load manuals ? If so are they comparable to anything these days I’m talking 30’s to early 60’s such as Remington Peters 157’s and the like how spicy are they compared to say a CCI209 or a Cheddite?

[Unclenick]

If you go back to the '30s, you are looking at either corrosive or mercury-based non-corrosive primers. The latter were famous for deteriorating in a few years, so it was perfectly possible, back then, to have weak primers in that format.

Another factor is that many powders have changed sources or specifications over time. Not Bullseye or Unique or Herco, AFAIK, but others have, so the powders with the same name today may behave a little differently than they did when the old data was written, making that old data untrustworthy now.

Probably the main factor, though, is that a lot of old data was developed in production guns and never pressure tested. Where it was pressure tested, it was often by a lead crusher or by copper crusher, both of which are notoriously inconsistent among different test guns and ballistic technicians. Until SAAMI developed the reference cartridge for calibration, you could have substantial disagreement between them. I’ve seen 21% documented for a 30 Carbine test among several copper crushers, and expect at shotgun pressure and with lead crushers, this would be worse for technical reasons. The bottom line is, again, to be wary of old data. Much of it is no longer safe.

[Jim Watson]

Another factor is the better gas seal of Power Piston and similar one piece wads. Loads are lighter than for card and felt wad stacks. A club member here broke a gun by putting a card wad load under a plastic wad.

[44 AMP]

You might also consider the huge change in the HULLS between paper and plastic. In some cases, literally everything but outside hull and primer pocket dimensions has changed.

[Jim Watson]

Right, and primer pockets too.
Does even Remington use #57s any more?

Back when I was shooting Trap, I knew people who were using fired 209s to swage out 57 pockets to take the more common Winchester size. Can you spell c h e a p ?


Old literature showed kits to reprime used battery cups for the real tightwad.

[smleno1mkIII]

I have old paper hulls that I’m trying to load because they’re period correct for my model 17 Remington 20 gauge. I’m using fiber and cardboard nitro cards and swaging up with the fired 209s is what I’m doing. I love the smell of paper hulls. The loads I’ve tried have been too anemic. They feel way weaker than the first firing or standard trap loads, but I tried some of the old loads in Federal Hi-Power hulls as a test with a string, and all that, and it stretched the hell out of the case and ripped the end of the case off. This was done with a cheap Mosberg, not my beloved Model 17. I’m just trying to get an idea of how much I need to reduce the charge to compensate for the difference in primers of yesteryear.

[Unclenick]

There is no single correct answer to your question. As pointed out in the previous posts, primers are not all you are compensating for. Also, you may have noticed that even modern shotgun shell load recipes are primer-specific. In other words, even modern primers are not all exactly the same as compared to each other, much less as compared to the old #57, so compensation is likely a bit different for each one.


CAUTION: The following post (or a page linked to) includes or discusses loading data not covered by currently published sources of tested data for this cartridge (QuickLOAD or Gordon's Reloading Tool data is not professionally tested). USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.

The only two really safe ways I know to do what you are trying to do are to send a series of your loads for professional pressure testing or to buy a Pressure Trace and measure the pressures from several commercial loads and then start upping your load until you get a peak pressure match. Both of those options are expensive.

A much less reliable option, but one that can be used to get into the ballpark, if done with some care, is to use a chronograph to measure your muzzle velocity. This can be tricky with a shotgun. SAAMI lists three methods, optical chronograph at 15 feet for lead shot, optical at 8 feet for steel shot, and, for either, inductance sensors at 3 feet. The inductance sensor velocity numbers are the ones listed by SAAMI in the SAAMI standard. I suspect the Magnetospeed V3 type chronograph may be the most viable amateur option, but if you don’t already have one, the lowest price I found was $400. Unfortunately, the less expensive model is “for centerfire rifles only.”. The way you would use it is to look at the manufacturer's published velocities for some commercial loads and compare your measurements to that claim. If, due to barrel length or diameter or choke or chronograph differences, they came out measuring some percent slower than claimed on the box, then I would assume you need to adjust all your expectations for published load performance by that same percentage. We already know your velocities with the paper hull and fiber wads are likely slower than plastic component loads, so look at the velocity you actually get for your current reloads and gradually increase the charge to get to the claimed load velocity that has been adjusted by the percentage for your barrel.

In theory, as long as your gun needs MORE powder to get to your adjusted published load data velocity than the manual says will achieve that velocity, your peak pressure should actually be a little lower than the original load produced. But any time LESS powder is getting you to the published velocity as adjusted for your gun, your peak pressure is higher, and it is not recommended.

Sorry it’s so complicated, but that’s sort of where it goes with interior ballistics.

[44 AMP]

Look at all the things people talk about changing the pressure in metallic cartridge reloading. And then consider that shotgun shells are much weaker, and the guns are built to withstand much lower pressures.

Back in dim distant past when I learned reloading basics, one of the rules was that shotshell loads MUST be followed exactly, and no deviation of components (other than shot size) was allowed otherwise you were running a significant safety risk.

[Jim Watson]

Right, while you can "develop" bullet loads, shot shell loading is pretty much by recipe.
The wildest I got was to split the difference on target loads and produce a "2 7/8 DE" shell.

[FITASC]

Not just differences between plastic and paper hulls, but plastic and paper/cork/felt wads all made pressures and velocities different