Benelli mp90s Rear Sight Plate

[Rudi]

Could any one confirm or advise.

https://www.glockparts.eu/products/bene ... ght-detail

Will this part fit any older Benelli MP90s version? I know that some modifications need to made to the stock grip, but it seems that my Rink Grip has already several mm of clearance over the stock grip it came with (which was a almost bottoming out for 10m shooting), so Rink is already adding this allowance into all the Benelli Grips?

Thanks!

Rudi

[-TT-]

The MP90S has come with this sight for some time, mine has it. It's quite nice, in fact.

I'm not sure if it bolts on to the old-style sight, but I have one here somewhere from an MP95E, I'll try to dig it out and see.

The Rink grip will probably need some very minor adjusting. I bought a left-handed one last year, and the back of the sight blade contacted the wood at one corner. It was a very slight amount of wood to remove, and all was good.

What front sight does yours have? The post-style ones may not fill out the sight picture as well as the wedge-shaped one that's currently on the MP90S.

[Gwhite]

It should have a small pin sticking out the front that has a small flat for the set screw that holds the fixed sight blades in place.

A word of caution: At least some of the set screws Benelli used are soft and the hex socket is oversized. They are suppose to take a 1.5 mm hex key. DO NOT attempt to loosen the screw without a few extra steps:

1) Get some Kroil penetrating oil, and put a drop down the hole for the screw and let it sit overnight.

2) Get a high quality (Bondhus are excellent) 1/16" hex key, or preferably several. 1.5 mm is 0.059 inches. !/16" is 0.0625 inches. The goal is to find a key that is a tight fit in the hex socket in the screw.

3) Make sure you get the best fitting hex key ALL the way down into the socket.

4) Cross your fingers and turn the hex key. With proper preparation, the screw should pop loose with a scary "snap", and then you are all set.

If the hex key slips, it will "wallow" out the hex in the screw. Then you will need to take it to a good machinist & drill it out with a left hand drill bit. McMaster Carr sells them...

I've done this on a couple of Benellis, and succeeded in getting the screw out. A friend used the supplied 1.5 mm hex key and had to go the drill route.

[-TT-]

I found my MP95E sight and yes, it looks like the adjustable sight will work per GWhite's fearsome instructions.

Here is a photo - the pin that holds the blade to the bracket is at the top of the photo, at the center of the sight blade (there is some sort of bushing on mine, additionally in-between). The pin is trapped by a setscrew in the center of the adjusting rod, and I can confirm that GWhite's suggestion of using a 1/16" hex key makes a perfect, tight fit. A 1.5mm has some significant angular wiggle. Never mind the 3mm nut on the right - I can't find the Benelli adjuster!

Perhaps you can do this without removing the sight bracket, but just in case... one more installation note from me. To remove the sight from the gun, you need to drive out the pivot at the front. In the earlier design, I believe it's often a single roll pin, but on my MP90S, it was two short pins, one on each side.

To remove the two-pin version, you have to drive both pins *in* just far enough to allow the sight bracket to come off. Then, you have to drive them *out*, completely through the hole in the frame, from one side. And of course drive them back flush (partway) when reinstalling.

[Gwhite]

I've never had to remove the sight assembly from the pistol. The forces required to get the screw loose are limited by what you can apply with a small hex key, and they just aren't that high.

TT: Thanks for the info on the sight pin design change. I haven't had to fight that battle, but I noticed the change in the diagrams over the years.

[Rudi]

You guys are the best, I’m going to take this all in and proceed with care when the plate arrives.

Thanks so much

[-TT-]

We Benelli shooters have to stick together, these days!

[deadeyedick]

Take an electric soldering iron and shape an end into a point then place point into the space in the Allen headed fastener and hold there for 5 minutes.
The screw will undo without nearly as much pressure and keep your anxiety levels low.

[Gwhite]

Heating the screw expands it, which can be counterproductive, although the thermal cycling can loosen things up. The soldering iron trick is essential if somebody used threadlocker on the screw. Fortuantely Benelli doesn't seem to do that for the sight screw.

One dodge I use occasionally is to cool the stuck fastener. If you buy a can of "duster" aerosol at a computer store, you can flip it upside down and get freeze spray. The rapid evaporation of the fluid will produce sub-zero temperatures very quickly.

A heat/freeze cycle or two can also help to free up stuck things. It works better with Kroil on the parts so that any minor crack that opens up between the parts will suck up the Kroil and not re-stick. I used this trick not long ago on a Steyr air pistol front sight screw that had the hex socket stripped.

[deadeyedick]

The soldering iron trick is almost essential when something like loctite has been used however I have found that it also provides great benefits when loosening a fastener that has not had a thread locking substance used.

The argument regarding expansion works in theory but in reality has not proved a hinderence in my experience. In fact applying heat to undo stubborn nut/bolts has been common practice for a long time.

[glockparts.eu]

The initial question, if the new rear sight plate fit older pistols. Yes it does, there is no change of the way to mount. Only change is that it is bigger why you need to make a change of the grip, please check here: https://www.glockparts.eu/products/bene ... ght-detail.
We have imported Benelli since 1996 and there has been no change to this part of the pistol, and most likely not since introduction in 1990.
As to the replacement there are some hints above.
We have done it rather simple.
-Place the pistol in a wise with grip removed
-Heat the tube with a lighter moving from side to side, while you have the hex key inserted and keep a slight pressure to unscrew. After a short while you can loosen the screw and remove the rear sight WHICH NOW CAN BE WARM.
-Mount the new sight and tighten again
The locktite used -243- will let go around 90-100 C (195-212 F), and harden again when cooled down.
This has worked just fine the last 25+ years :)
Leo Nielsen
Denmark

[-TT-]

-Heat the tube with a lighter moving from side to side, while you have the hex key inserted and keep a slight pressure to unscrew. After a short while you can loosen the screw and remove the rear sight WHICH NOW CAN BE WARM.

Great trick, thanks!

[Gwhite]

Benelli must have gotten a bad batch of screws at one time, because the fit of a 1.5mm hex key into the set screw that holds the blades in place is very loose in most pistols, and it's easy to strip out the socket in the screw. It turns out that 1.5 mm is 0.0591", which is perilously close to 1/16". Because hex keys tend to be slightly undersized & the screw hexes are oversized, you can often get a MUCH more secure grip using a 1/16" hex key.