Colt conversion bushings?

[Lostsheep]

I need an education here. I have a Colt upper with the large (aprox .315) front takedown pin. I want to put it onto a regular sized lower. I made a concentric conversion bushing for it out of 17-4 and everything appears to be tight fitting.



After I got done, I found this conversion bushing and noticed that it is not a concentric bushing but there is nothing to index the offset once installed.

http://www.brownells.com/.aspx/pid=24949/Product/AR_15_M16_PIVOT_PIN_ADAPTER_BUSHING

What gives here? Did colt change the size and move location of the hole in the lower receiver? If so, does anybody know how much? I guess I'll have to measure the hole to hole distance more carefully and see but I am hoping someone can help me.

ETA:
Is there a safety issue here?

Thanks

[Pofoo]

[QUOTE=Lostsheep;6041452][What gives here? Did colt change the size and move location of the hole in the lower receiver? If so, does anybody know how much? I guess I'll have to measure the hole to hole distance more carefully and see but I am hoping someone can help me.

Yes, larger hole and offset center.
I have a offset pin that I use with my Bushmaster (standard dia hole) upper and Colt (large hole) lower. Not sure if it works the other way around.
Or, you can machine the smaller hole larger
Let us know if you find a drop in bushing that can be purchased.

[Lostsheep]

Yes, larger hole and offset center.
I have a offset pin that I use with my Bushmaster (standard dia hole) upper and Colt (large hole) lower. Not sure if it works the other way around.
Or, you can machine the smaller hole larger
Let us know if you find a drop in bushing that can be purchased.

Well here's the one that brownells sells:


and here's one for the opposite problem and I assume it's what you have.



Do you have calipers or any other way to measure the offset? Knowing that number would help me immensely.

I should probably just order the $3 part but then I have to wait for it. I can make one in 15 minutes or so and be up and running asap.