So I was looking at building a few P320 lowers in 45 ACP so that they can be used in all calibers.

I wanted to see if anyone here has tried to build one yet and have any advice on what 80% lower is best and what jig is the best? Bend the tabs best with a hammer or a press? Thanks for the help and advice!

I have looked into doing it a few times but decided not to after the cost comparison. The 80% lower blanks are cheap but it's all the small parts to finish them off that quickly adds up. It would be more cost effective to just buy a complete 320 and then go from there. It was a couple $100 more to build one than to buy one. The 320 80% builds are not like the glock 80% builds because the glock market is flooded with parts that can be had for a good price and there is a much bigger market for custom stuff.

I decided there was no point to doing a 320 80% build until either the small parts prices came down or the custom market took off.

Edit-- justvto add...I did my research about 6 months ago so it is possible the prices and availability has changed.

And I have nothing against 80% builds. I have done 2 glock builds. And I hate glocks.

See what you're talking about since I get LEO discount on SIG it would cost me $150 more to build a ghost SIG.

I could buy them and then sell the gun part and build 80%!

Just to help everyone wrap their head around this, the metal part with the serial number is the "lower" that would need to be 80%.  None of the rest of the parts, including the grip frame are part of this 80% lower.



If you had a press brake and appropriate dies, you could make this from a 0% in a couple presses, I would suspect.

Um..you do know they are selling "80%" trigger groups for the SIG 320? You have to drill a few holes and then bend the rails down. The kits I looked at have two pieces. The trigger group blank goes between the two pieces and then you press or hammer them together which bends the rails down. It is pretty simple.

The only thing that stopped me was the price for the small parts.