[davetex]

Hey Frog, I’ve got a question for you. I bought this upper to go on PSA lower:

http://www.jsesurplus.com/custom16hbarmidlength1x9flattopuppercompletestandard-2-1-1-2.aspx

I want to get a folding rear back up sight. How do I know which one will match up with the already installed front sight?

By the way I upgraded the upper with a nice quad rail and a Badger charging handle.

[smokingfrog]

If it’s an F marked front sight, I think any standard sight should work fine.

Here’s a couple of nice ones.

http://www.lwrci.com/p-237-lwrci-skirmish-sight-buis-rear.aspx

http://store.troyind.com/Di_Optic_Aperture_DOA_Folding_Rear_Sight_p/ssig-doa-rfxx-00.htm

Magpul makes a plastic sight that is fairly inexpensive but durable.

[smokingfrog]

Back Up Iron Sight for your AR-15, M4, M16A4