I need someone, preferably more than one person with a stripped lower to measure the depth of the tiny hole that houses the front take down pin retention spring. I say more than one person because I'd like to make sure I get the depth right and different brands may be a hair off. I have an HBAR Colt that has a threaded front take down pin and uses a screw on the left side to anchor the pin. I want to ditch the hokie screw and install a regular take down pin. Brownells was suppose to have a replacement for this and they sent me a pin that was 1/4" longer than the receiver with a detent ball also on the outside of the receiver. A very cheesy fix, would it work, yeah, but it's not correct. So I bought a standard front pin, detent pin and spring from my local shop and headed home. I take down the rifle to install said parts only to see there is no hole. I guess since Colt wasn't using that style of take down pin, they decided to skip drilling that hole. So, I can drill the hole myself but I need to know the correct depth so the spring has the correct tension on the detent pin. I guess the easiest way to measure would be to use a small enough drill bit and insert it, flat end first, mark it with tape, remove and measure. This would help me out alot and I would really appreciate it. Thanks a bunch if you can take the time.