Colt Defense Integral web sear block?

[brushy bill]

I have a lightly used Colt Defense rifle with has an integral web style block that is solid with lower receiver. Can I replace the half circle carrier with a M16 type BCG or will the block preclude this?

Will I need to replace the bolt as well as carrier or will it work with the new carrier without modification (i.e. drop in)?

The polymer buffer...what should I replace this with? Will it require a new spring?

Thanks much for your help.

[m4fun]

Ooh - a pic here would really help. I think you should be good with a full auto carrier, but lets let other folks chime in here. I think I had a Colt 9mm carbine that had that sear block and the 9mm BCG has always been FA.

You shouldn't need to replace your bolt - just wouldn't make a habit to swap in and out of different carriers.

If you have an old polymer buffer, I would definately look at getting a Heavy or "H" buffer. Then again, if it aint broke...spring - not usless you have to.

Honesly - I would look at getting some "Spare" parts which really means get some upgraded/reliability parts from G&R or BCM as far as springs, pins, all LPK and even another bolt. If you use a reliability replacement part, you now have an original spare.

Welcome to the spending of money :) Next you'll look at stocks, uppers, optics, mags...

[firemike]

The BCG change does not contact anything the Lower Rec. Forging - so it should be fine.
Th block is designed to stop M16 FCG parts from fitting - and some common Auto Sear designs.

There is a very good thread above on Buffer Weight - check it out.

I can't think of a reason to change the spring - just my opinion.