I found that old-flare report I was thinking of. Hope it's okay to copy and paste, as it's very instructive.
Source:
Cape Dory Boats - View topic - Annual Meeting of the NE Fleet!
Outdated 12 Gauge pistol Flares: - Of the ~80 outdated 12 ga. pistol flares only two did not display the flare while in the air. All flares left the flare gun (some dating back to 1992.)
Outdated Handheld Flares: - Most of the outdated handheld flares did not ignite via their installed scratch cap. (My batch was representative with 5 out of 6 not working.) All could be ignited from another handheld flare already burning. All the outdated Skyblazer handhelds did not
work. (Note; Mfg by Skyblazer, Anaheim, CA. Skyblazer' was bought by Orion,
Peru, IN. They no longer mfg "Skyblazer handheld flares.") Most of the outdated SOLAS handheld flares worked well!! And, they appeared 10 X brighter the USCG approved handhelds.
Skyblazer Rocket Flares: - Most of these worked as designed giving performance similar to the old version of the 12 gauge pistol flares. Their firing mechanism was intuitive easy to use under stress. These flares are usually in a sealed 3-Pack, which may contribute to their
reliability, although I do not know if they were past expiration date. (Which might suggest placing our loose handheld and 12 Ga. pistol flares in a zip-lock bags and sealing them?) Currently mfg by Orion.
SOLAS Parachute Flares: - Most of the outdated SOLAS parachute flares (Paine Wessex) did NOT
work. The biggest problem was with the firing mechanism - falling apart as you removed the bottom cap. This mechanism is very fragile. When using these you must take time to carefully read the instructions and manipulate the firing mechanism gently. All in all, not a good combination for
emergency equipment. The ones that were able to be triggered did function. And as with the handheld, the SOLAS parachute flares were multiple times brighter than anything else, went higher and burned longer. Their use in an
emergency by people not knowledgeable with the firing mechanism is very iffy. I do not plan on
buying more SOLAS flares until this trigger mechanism is refined, strengthened and simplified.
The old style 12 Gauge vs. new style 12 Gauge Pistol Flares: The typical old style 12 gauge pistol flare is a paper shell with a wax coating ~2 inches long with a max height of 250 feet. As I understand it from Defender, these are no longer available or approved. The old 12 gauge with its paper shell and wax coating is susceptible to moisture intrusion over time. The new style USCG approved 12 gauge pistol flare is made of a plastic material (similar in appearance to the Orion / Olin flare guns), ~3-1/2 to 4 inches long (fits flush with the end of the flare pistol) and has a max height of 500 feet with a slightly longer burn time. The plastic appears to be better sealed against moisture.
25 mm Pistol Flare: - An Orion 25 mm pistol flare was fired for comparison. It goes VERY high and multiple times brighter than the 12 ga. (obviously.) The 25 mm would significantly enhance being seen over the 12 ga. or the Skyblaster flares. Though costly, I plan on stocking more of the 25 mm flares.
Some not obvious or expected observations:
12 Ga. Flare Guns: - Out of 25 to 30 used, we had 3 flare gun failures!!. A new Orion flare gun blew the muzzle end off on the first round! A second Orion flare gun developed a longtitudal crack on the bottom side of the muzzle. A Olin flare gun would not completely close the breach resulting in a misfire of the installed flare. The flare was installed in a second Olin flare gun and fired successfully. This is a 10 % failure rate people. For Emergency
Equipment this failure rate is very HIGH!! I'm going to bring this to USCG and manufactures attention. Orion has a lifetime warranty. I am going to try to use this program for my malfunctioning Flare Gun. (Orion formally was marketed under the Olin name.)