How accurate are aftermarket sight numbers?

[John Hearne]

I'm looking to buy a specific configuration of sights for my Sig. There is no single set out there that does what I want. I'm looking at using a Dawson front and an Ameriglo rear. Both companies list heights that are consistent with the factory sights so in theory, they should work.

My question is, how accurate are those numbers and are they likely to actually regulate the gun properly?

[guymontag]

Dawson sight measurements have been on the $$ for me, I can't speak for Ameriglo though.

[GJM]

Dawson lists dimensions, but I can't easily find them on the Ameriglo website.

I have experienced a surprising amount of variation in Sig P series pistols of the same caliber, especially in .40, .357 and .45, so I wouldn't bet either way.

[Hi-Point Aficionado]

Dawson will cut you a corrected front sight and send it to you if there is an issue. Order what looks closest, shoot it properly at a measured range (they suggest 20 yards), and have a set of 8" calipers handy if they don't hit to POA because Dawson measures everything in thousandths of an inch and will want to know your current sight radius. They're calculations can be fiddled with here:

https://dawsonprecision.com/sight-calculator/

I've got a front sight in their custom queue for my 40 caliber USP as they used a 45 ACP version when designing the sights so I just went with what looked most likely to work when I ordered. Wound up ~6" low (my 155 grain LSWC, 180 grain coated flat nose, and 180 grain jacketed factory ammo obviously land in different spots and 6" was close to the middle of them all so went with that) and their customer service was very quick in getting a ticket to the CNC mill to sort me out.

[taadski]

I've used Dawson fronts of varying heights to regulate with an assortment of different brand rears on Sigs; to include stock factory (#8 = .160T), Heinie, Warren, Ameriglo (although only their suppressor versions personally), etc... Just remember some companies include the dovetail height in their listed dimensions, while others (like Dawson) do not.

[OnionsAndDragons]

If you get a Dawson front, they will get it right. You nay have to do done work and send it back, but it will eventually be what you want.