I've one of these sets and I've had it for over 20 years. Has covered every fastener I've come across in that 20 years.
Other than that, if it's something odd, post a pic. of it for us to identify.

 

I have no experience with the Beretta 21A, but Brownells offers a wide array of screwdriver bits. I'd be surprised if they didn't have exactly what you're looking for.

 

Thanks guys. I’ll take a look. The 21A screw slots are almost literally razor thin. Don’t be fooled by the greatly magnified photo.

 

I find electrician blade screw drivers to be the best for slot type firearm screws. Like this picture. There is also screw holders that have the same profile and have used them as well, I pull the locking sleeve tight after inserting and use it to remove, no dropped screws as well.

LOG

Klein Tools 3-Piece Slotted Screw-Holding Screwdriver Set

 

McMaster Carr, measure the screw slot, go on their site, precision screwdrivers, pick what ya need, order.

 

I can see where they might be cheaper to manufacture, but really, why does anyone use slotted screws anymore?

 

Anymore? These screws are over 30 years old, along with the gun.

 

The thinnest one from Brownell's is too thick for a Beretta 21 (and other really fine slots as well).

However, you can get the right -WIDTH- tip from Brownell's and grind your own. There is a jig for doing this but with reasonable care you can do it with a trued stone wheel on a Dremel. Go very lightly, move the tip laterally (sideways) as you grind you spread out any uneven grinding. You can polish a bit if you like.

I used to have one of those jigs, but gave it to an old girlfriend's dad as he was really fascinated with it. I've used the "Dremel" technique with pretty good success. The key is to keep the grinder still, and slowly move the screwdriver tip. Or, that's what works for me the best.

 

The Chapman Gunsmith Driver set has been with me for years and used very frequently. Well made and never buggered a screw. I highly recommend them.

Chapman MFG 8900 Gun Owner Standard Screwdriver Set - Slotted, Phillips & SAE Hex Bits - Set Offers 24 USA Made Insert Bits, Mini Ratchet, Spinner, Screwdriver Handle + Extension (Yellow Case) - Screwdriver Bit Sets - Amazon.com

Chapman MFG 8900 Gun Owner Standard Screwdriver Set - Slotted, Phillips & SAE Hex Bits - Set Offers 24 USA Made Insert Bits, Mini Ratchet, Spinner, Screwdriver Handle + Extension (Yellow Case) - Screwdriver Bit Sets - Amazon.com

www.amazon.com

And they’ll do a good the job on your 21A - as the do on mine.

 

Brownells has other screwdriver bits that are thinner than those that come in the boxed sets. I bought an add on set specifically for Browning A-5 shotguns that has very thin blades, one of which would surely fit your grip screws. When I go to my shop later today, I’ll get the numbers off the bits. They can be ordered separately from Brownells.

 

Thanks!

 

Go to Brownells, get one of their screwdrivers, they are very nice, and some bits, but also get the rotary stone and some spare bits that you can grind to the size you want. The grind stone goes in a drill press (although I suppose you could carefully clamp your cordless drill in a padded vise), the radius of the stone matches the radius that they grind their bits to, so very easy to thin a bit to fit anything.

 

Hand file or bench grind an existing screwdriver to fit perfectly? That's what I've done in the past when I needed a special size slotted screwdriver. Then I mark it with a soldering iron so I know which one it is five years later when I need it again.

 

I have the Chapman set as well and added the extra bits, to it, by drilling holes for them so all in one box. It is a go to set.

LOG

 

I have the Chapman set as well and added the extra bits, to it, by drilling holes for them so all in one box. It is a go to set.

LOG

View attachment 625750

THAT is the same exact setup I have used since 1990. Almost any size bit you will need is available from Chapman's but you really need to learn to custom grind bits to fit specific screws - it is not really that difficult to do. This is how you keep from trashing screw slots.

 

My luck, as usual. 🤦‍♂️🤷‍♂️ I need the Magna-tip 210-1. Currently on back order at Brownells.

 

I've had a Wheeler set for many years and there is no type of screw that I have come across that I can't safely remove.

 

As promised, the thin Brownells Magnatip bits are 210-1, 240-1, 300-2, 340-1. The first number is the width in thousandths, .210”, .240“,etc. The -1’s are .020” thick and the -2 is .025” thick. I feel sure you could make one of these work on your grip screws. They fit anyone’s magnetic screwdriver handle.
I really don’t mean to disregard others opinions on tools but in 40+ years in business, I have used lots of screwdrivers and the Brownells are the best available. Lifetime guarantee to boot. If one breaks, just tell them, no need to send the bad one in for replacement.

 

As promised, the thin Brownells Magnatip bits are 210-1, 240-1, 300-2, 340-1. The first number is the width in thousandths, .210”, .240“,etc. The -1’s are .020” thick and the -2 is .025” thick. I feel sure you could make one of these work on your grip screws. They fit anyone’s magnetic screwdriver handle.
I really don’t mean to disregard others opinions on tools but in 40+ years in business, I have used lots of screwdrivers and the Brownells are the best available. Lifetime guarantee to boot. If one breaks, just tell them, no need to send the bad one in for replacement.

Right. I already figured out I need a 210-1. Just need to find one. 👍