One thing I hate about the Colt SP1 is the large pivot hole and the need to use an adapter screw to make the large hole accept a small hole.
Thinking about I I decided to try to make a small pin version.. And here is my my first experiment..

1. Parts:
It took a bit of brainstorming to figure out what I should use. I ended up deciding to some how use a KNS pivot push pin as my method of disassembly. I chose the KNS pivot pin with the stud thinking the ball bearing would stick out more due to the stud. Since I don't have a non stud version I couldn't confirm it, but what I chose worked out great.
This in conjunction with offset adapter bushings which were originally meant for an upper with large hole pivot. I took 2 bushings and filed it down to fit the lower instead.



2. Installation:
I decided my first attempt to not use the stud.  So one bushing I filed to the width of the right wing of the SP1 pivot hole so it fitted flush.
The other bushing I filed it to the depth of where the ball bearing of the KNS pin.  This is the outcome.. A fast detachable pivot pin.





As you can see it fits perfectly in.  As for the upper and lower lock up, there is a slight bit of rattle, but it is much less than many regular AR-15s I've dealt with. I plan to see what I can do about it since I like tight lockups.

Now the decision to file down the bushing to fit the KNS stud or just leave it as is. I'm thinking to add the stud due to knowing that running this in full auto will put some stress on the narrow wall of the bushing.

I also have a couple more ideas to help prevent the bushing alignment to roll from each other.. But then again if it does it would lock up tighter.
Wear and tear I'm not sure about.

Probably Wil add some JB weld (or hot glue to keep it non permanent) to make the bushing a permanent part of the KNS pin.. This will also help keep that min in alignment and not roll.. Plus the flat side will always be oriented to the left like in a lower with a retaining pin (cosmetics)

If you have ideas and suggestions, I would love to hear it.

I think you have figured out the secret sauce to the large/small pin issue! It's small enough not to be an issue. Congrats. Now go sell some...

I tried it at the range with my buddy the other day. I took his upper and popped it on without tools.  It did take longer than a lower with small pin, but it was faster than needing a screwdriver.

I did loctite one of the adapters to the KNS pin.  This way I had only had to deal with 2 parts. Installing my friend upper was a tight fit, but it worked. It does feel weird to press and pull the pin at the same time.. but that's just how KNS pins work.