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Benelli MP90 trigger group.

Posted: Tue Apr 06, 2021 7:04 am
by Mike38
Calling all Benelli experts!
I bought a trigger group for a Benelli MP90 to install on my MP95. I have a couple questions.

First, with the original plastic trigger group, I can remove the bolt with the trigger group in place. With the new aluminum trigger group, I can not remove the bolt. What's up with that? I'm going to hate having to remove the trigger group for normal field strip cleaning.

Second, the original plastic trigger group has a detent ball that holds the forward (front) pin in place. The new aluminum trigger group does not have this. What holds the pin in place? Does the MP90 require a different pin, or a threaded machine screw?

Thanks for any help! (Sure wish I could call Larry!)

Re: Benelli MP90 trigger group.

Posted: Tue Apr 06, 2021 12:01 pm
by Gwhite
They made changes to the disconnector in the newer designs that interfere with removing the bolt with the trigger assembly in place. Depending on the cutout for the trigger guard in your grip, you can often pivot the trigger assembly down on the rear pin & pull it forward. This allows you to take the bolt out without removing the grip.

The new style front pin is some sort of screw. Buying a new pin won't help, because there are no threads in your frame. If the two bumpers on top of the trigger assembly are fresh, they should put enough tension on the old style cross pin that it won't "walk" out very quickly. I'd try that & keep an eye on it. If it stays put OK, you are good to go. If not, I'd drill & tap a hole in the front of your trigger assembly & install a spring loaded plunger screw like they used in the old triggers. You can cannibalize your old trigger for the screw, but it you want to keep it intact as a spare, McMaster Carr has metric spring plunger screws:

https://www.mcmaster.com/spring-screws/ ... nt~metric/

Another option is to see which direction the pin wants to shift on firing, and make a pin with a head on it that prevents it from moving in that direction.

Re: Benelli MP90 trigger group.

Posted: Tue Apr 06, 2021 6:14 pm
by Mike38
Thanks for the reply. I assume it's safe to shoot the way it is now? Multiple dry fire (plug in of course) and all seems well. The pin that holds the trigger group in place actually had to be tapped a couple times with a brass punch to be seated, so maybe there is enough downward pressure to hold it in place? I guess I'll have to get used to disassembly of trigger group for cleaning. Not that it gets cleaned that often anyhow. I have found that SK Pistol Match ammo shoots very clean and I can get away with 500+ rounds before cleaning.

Re: Benelli MP90 trigger group.

Posted: Tue Apr 06, 2021 6:33 pm
by Gwhite
Just keep an eye on the pin until you see how it behaves. The rubber bumpers will mash down over time, and the grip on the pin will loosen up, but that could take years.

If you need new bumpers, you may be able to get them from Larry's Guns (Cardinal), but you can make your own from O-ring cord stock. I've found that McMaster Carr #9407K12 1/8" Durometer 70 (https://www.mcmaster.com/9407K12/) works pretty well. The holes in the trigger are 3.5 mm in diameter (0.138"), and actual diameter of the cord stock is 0.139", so they won't fall out too easily. Cut them to ~ 10 mm length. You can adjust how tight they are by fine tuning that.

Re: Benelli MP90 trigger group.

Posted: Wed Apr 07, 2021 7:59 pm
by Mike38
Thank you for the valuable information.