What is the Thread Size on the Rock Island 1911 45ACP with the Threaded Barrel?

Non-PSA Products Pistols (Non-AR)
1

This one -

https://palmettostatearmory.com/rock-island-gi-standard-fs-threaded-45-acp-8-round-pistol-parkerized-51473.html

2

The spec sheet off of the Rock Island site says 1/2x28

1800×1197 427 KB

3

That’s odd. .45 is usually .578x28.

1 Like
4

I have an adapter, 1/2-28 to 5/8-24.

So I could make that work.

But how does a .45 or .458 diameter bullet, reconcile with the minor diameter of 1/2-28 ? Which is about .45.

5

I’d contact Rock Island to make sure that’s the correct thread pitch.

1 Like
6

You need to make sure your adapter is rated for .45. 1/2×28 to 5/8x24 is usually 5.56 to 30 cal.

1 Like
7

Hey i hate to necro this thread but i have not been able to confirm this with certainty anywhere on the internet. Did you find out if the thread pitch is really .578 x 28 (normal for .45) or 1/2 × 28 (doesnt make sense, normal for 9mm or smaller)? I am wanting to buy this gun but its crucial for me to confirm this. I will be using a Griffin Bushwhacker 46 with a cam lok piston and they do not make a .45 cal barrel adapter in 1/2 x 28. And I cant use a 1/2 × 28 to .578 x 28 adapter because the suppressor would be hanging like 3 inches off the end of the barrel at that point.

8

@LBL
Any update on this?

9

With interest rates going up all of my extra income is going to pay off my HELOC.

The Rock Island 45/1911 is interesting, and PSA’s price made it do-able - until Uncle Powell put the screws to the disposable income of 100 million Americans.