Is it always the cartridge in a particular position in the magazine, for instance the very last, or the next-to-last?

First thought: Fire it almost dry, or lubed only with a bit of grease on the slide rails and nowhere else. Make sure there's no oil in the magazines.

This is one of those "tough dog" problems that're very difficult to solve.

How old are the magazine springs? How old are the magazines? What brand are the other two magazines you refer to? How old is the pistol, and do you know how many rounds have been through it? Has the locking block ever been changed? Did you buy it new, used? I'd suspect the magazine springs are shot, but out of five magazines maybe not. What poundage recoil spring did you buy, and from who, Beretta factory, Wolff? Probably not the issue, but how does the ejector look? I use Wolff extra power magazine springs as a preference. When did the pistol start having malfunctions? Has it ever worked w/o malfunctioning? You may want to take it to a qualified Beretta gunsmith or beretta themselves and have them check it out. Mine's worked flawless w/o a hitch for over 19 years w/ anything i feed it, and thats w/ either a 14lb or 15lb Wolff recoil spring as opposed to the 13lb factory original.

Originally Posted by Steve M1911A1

Is it always the cartridge in a particular position in the magazine, for instance the very last, or the next-to-last?

First thought: Fire it almost dry, or lubed only with a bit of grease on the slide rails and nowhere else. Make sure there's no oil in the magazines.

This is one of those "tough dog" problems that're very difficult to solve.

The cartridge position in the magazine is compeltely random. I've had it FTE on the second round and near the last round.
There is some hope though. I bought a box of 50 Federal 147g cartridges to see if it would shoot them. It did flawlessly. I also shot some hydrashock 124g cartridges with success. So that is encouraging. I really want to shoot 115g b/c they are so inexpensive and I like to shoot a lot. Maybe I should get a lighter recoil spring just for the 115g stuff. I appreciate your help.