doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Anyone pressure tested old ammo?

With different methods and equipment and perhaps placement of pressure devices used complicated by whether a proof or average pressure is used, has anyone tested OLD ammo to see the pressure truly measures. There is some still out there.

Tom Armbrust related (in a personal conversation with another forum member) that he had attempted to pressure/speed test vintage shotgun ammunition, but the results were too inconsistent to be reliable.
He felt this was from:
1. deterioration of the primers (rather than the powder)
2. stiffening/hardening of the case and wads occasionally producing pressures higher than published data for that period

My experience is that pre-WWII ammo(basically anything roll-crimped) is unreliable. I had paper cases fracture and saw lots of confetti, possibly due to fracturing wads. In my samples, FTF's were common and I found some ammo that appeared pristine could be 100% duds.

I saw a marked improvement in post-WWII ammo, essentially any paper shell with a pie-crimp. I attribute the distinct change to the R&D done during the war and the standardization of good primers. I didn't care to shoot anything that appeared to have been wet or otherwise mishandled. However, ammo from the 40's and 50's that appeared case fresh did, in fact, pattern, chronograph and ignite with the same reliability I'd expect from ammo made last year. Grouse flushes are too hard to come by to use untrustworthy ammo yet, For the last 20 years I've used 1950's ammo exclusively for my hunting.

I don't doubt that Tom made the observation mentioned, but I'd be surprised if he intended to make a blanket condemnation of "old" ammo.
If someone were interested enough to pay $5 per sample, I'm pretty sure Tom Armbrust would be willing to test it. If it were me, I'd pick a lot that was visually appealing and dissect a few to see that the shot wasn't fused into a slug by oxidation. If there were no obvious anomalies, I'd send a few over the chronograph onto paper. If the extreme spreads were reasonable and no obvious clumping of shot on paper, I'd send 3 each of a couple varieties to Tom.

I will note that Federal was the last major US maker of shotshells to abandon the roll crimp & adopt the pie crimp. I don't recall the exact date but i believe it was at least sometime into the 1960's. I do recall that when I first became interested in shotguns in late 1954 & for several years thereafter Federal was advertising their "Frangible" top wads which disintegrated upon firing so as not to disrupt the pattern. These wads would no doubt show confetti on firing, which they were intended to do.

Confetti is not confined to old shells, either. Last year, at the Fall Southern S x S, I bought a flat of 16 ga. RST spreader loads to use in my very tightly choked Elsie. They worked well, and I qualified to shoot in the Challenge Event, but what a mess! Never saw so much paper in the air coming from a shotshell. Other shooters were noticing and laughing, too. Still got four boxes of 'em.

I shoot old roll crimped shells regularly in this gun at doves. They kill doves fine, but have a much higher incidence of bloopers than the pie crimped paper shells, as Mike noted. I get the distinct impression that pressures in some are extremely low.

SRH

It depends manner and environmental conditions it was stored in, but in general I would avoid using real old ammo. At best one is likely to experience degraded performance or at worst burst barrel if barrel lodged charge or partial charge is not discovered and another cartridge is loaded and discharged.