Having that extra 1/4" seems to limit holster selection. Unless the holster has an open bottom. I have not tried any holsters that are closed bottom and specifically 4". I recently sent an email to Galco to ask if it would fit in a Vertical Shoulder Holster for a 4" 686. Their reply was

"I would recommend against the VHS holster. The VHS is length specific, you can assemble the Miami Classic style system, it will fit, you need 1 each holster, ammo carrier and harness.."

I don't think they know if it will fit or not without physically trying it. The M69 is still a large revolver, I would prefer to wear it in a vertical shoulder holster verses a Miami Classic horizontal. I think it would be easier to conceal and more comfortable. I am tempted to buy a vertical holster and keep my fingers crossed.

What is your holster selection and what 4" holsters have you found it will fit in?

I've been using N frame holsters for mine. The extra 1/4" is not an issue in close bottom holster.

I have been using several L frame 4 inch open bottom holsters. The extra 1/4 inch sticking out is not noticeable to me and has not caused any issues.

Ordered a holster from Lobo and it fit perfectly, just let them know it is for a Model 69.

None of my 4" holsters, closed bottomed or not, have had a problem with the Model 69. Mostly K frame holsters to boot!

Thanks based on that, I am going to order the Galco VHS104 and gamble that it fits.