Home Forums Hunting & Shooting Ask The Gunwriters 6x45 A.I. vs 6mm TCU

Does anyone know if there is any difference between these cartridges? I can't find a case drawing anywhere for the 6x45 A.I.

Thanks

Guessing it would look just like a 223AI but with a slightly bigger hole in the neck.

If there is a difference I cant imagine either having a distinct advantage over the other. I shoot a TCU and its replaced 223ai as my "go to" small cal. favorite. With an 8 twist and 95 gr Bergers the accuracy over distance is amazing.

Scott, don't you have a 6x45?

I do

How does it compare to 223 AI on deer? It looks like the 223 has more bullet options...

The ones on either end are 6x45, the black tipped are 223AI and the remaining two are a 6x45AI, well I necked up a 223AI and seated a 6mm bullet in them.

I've only killed one deer with the 6x45, but in my mind I think the 223AI is a better mousetrap with the bullets available for it, though you only need 1 GOOD bullet.

The 10pt went maybe 20 yards after taking a 70gr Ballistic tip right behind the shoulder (clipped the offside shoulder) with the 6x45. I like the cartridge and thinking hard about a 7mmTCU just cuzz.

In the past I owned a 6mm TCU super 14" Contender. Now I own a 6x45 in a Ruger #1.

I can't imagine buying custom dies and a custom reamer for the 6x45 AI when it's doubtful you'd gain any appreciable velocity over the 6mm TCU which is pretty much already an A.I. Besides it uses already a standardized reamer and factory dies....

GH

Agreed, I'd go 6mmTCU for those reasons, albeit you could run a 223AI bushing die for the 6mmAI, but it still don't make sense.


If there is any difference in case dimensions it ain't but a RCH.

How much do you think the 6 tcu would gain over the 6x45 say with a 80 gr Hot-Cor/Deep-Curl?

No idea, likely as linear as the 223/223AI comparison.

I do know the smith had a 6x45 reamer but no 6mmTCU. Another deciding factor...

How fast does you 223ai push those Sciroccos?

3K

Do you switch them out with Amaxs?

Although this doesn't really address the 6x45, Hornady states, "In fact, there are two versions of the 223 expanded to 6mm. These two,the 6mm/223 and the 6mm TCU(Thompson/Center Ugalde) are similar but not interchangeable. However, the 6mm TCU reloading can be used for the 6mm/223, starting at the lowest listed load and carefully working up."

Thinkin we kinda already know this, though.

I too would tend to believe that any difference between the 6mm TCU and the 6x45AI would be small being both share a 40 Degree shoulder arrived at via fire forming.

The only benefit I see to the 6x45 or 6tcu over the 223 and 223ai is they are legal in Wyoming where I goat hunt.

I had a 6x45 for a short time but never got to shoot any deer with it.

I remember getting a hair over 2900 with the 80gr Hot-Cor from a 22" barrel...

According to the cartridge drawing in the Sierra Manual, the 6mmTCU has a 40* shoulder. (Which would be the same as the A.I.)

In my experiements with the .223 Rem vs. the 223 Rem A.I., I found the A.I. version to be nearly the .222 Rem Mag. If you look at the 6x45 vs the 6x47 (6mm/.222 Rem Mag) you can see that it gains nearly 200 f.p.s. with the 80 gr. bullet.

Without actually building one, that's about the closest guess one will likely find...

Good info Grasshopper, I figured probably 150 fps...