Oops, I meant Extra Light Target Loads (Walmart in Mechanicsville even had some of those puny subsonic ones with pic of feather on front of the box). The ones with slivery feather on front of the box are a bit too wimpy for my taste. Look, I shot 4 boxes of WELTLs out of my Remi 31 with AL frame (it's marked 12GA for 2&3/4 shells or shorter) that unlike 870 does not lock into steel barrel extension. There was no damage and I'm happy to report no fillings fell out of my jaw.

I don't know what avg. gp is, but I'm sure it's well below ceiling value of 650bar allowed for std. Euro 70mm field loads.
On the other hand some of those 65mm 'Super Duper' 1300+fps English game loads will kick the snot out of you, and they aren't likely to be of lower pressure than WELTLs.