Thread: Tikka 6x45 / 6mm-223

I'm not working today due to work being suspended because of the Cyclone happening here in Australia .
Perfect timing because my old T3 .223 Tikka is back from Trentech ( Gunsmith ) with a new 6x45 / 6mm - 223 barrel , so I started the fun job of putting stuff together .

I have over the last 6 months acquired bits and pieces for this old Tikka .
I found a GRS Stock recently secondhand at a price that I couldn't go past , so even though this was not my original idea , I have a Tikka Super Varmint Stock which I was going to use and still may if I don't " Jive " with the GRS . This Rifle is going to be used mainly for Targets , but will ride along in the Ute/Buggy at times and I'm not sure about the GRS stock for this application . It definitely isn't a walk around/hunting stock in my view .
From the research I've done it should launch a 85gn projectile in the region of 2750fps - 2900fps depending on how brave I am and powder choice .
I had purchased new Alloy bottom metal for it when it was a .223 , so that is being used instead of the crappy Factory plastic one .
A 6 round Waters .223 magazine that allows you to load out to 2.6 inches without any other modifications to the Rifle is being used so that the longer / bigger 6mm projectiles won't protrude down into the case robbing space for powder .
The Dummy rounds I sent to the Gunsmith ( the barrel was throated 20 thou jump for the dummy rounds I supplied using Sierra 85gn hpbt projectiles seated out reasonably long ) feed perfectly in the testing I have done this morning ( all dummy rounds , I don't like cycling live rounds at home )










Here is a photo of a Factory 55gn round compared to what I'm going to be throwing now .

@phillipo did you have one of these ?

She's purdy. Decently chunky barrel. What's it weigh all up?

Originally Posted by Pommy

She's purdy. Decently chunky barrel. What's it weigh all up?

That's a good question about the Weight .
I just put it on the Wife's electronic kitchen scales and it is to heavy for them , they max out at 5 kg
As I said in the first post it's basically going to be a fun informal Target gun , but if the Chambering shows promise I will be tempted to get a lighter barrel and put it into a lighter/more appropriate stock / lighter optics and mounts etc

you will love it.

I like it!

Now you could go with the 204 case and squeeze a bit more out of it, won't need to overload

Nicely thought out project. Do keep us posted on its performance!

Originally Posted by SmokeyJason

Now you could go with the 204 case and squeeze a bit more out of it, won't need to overload

Absolutely …….. but .223 Brass is overflowing in my cabinet and will never be an expense or problem to acquire.

I shoot Sierra 70gr hp projectiles out of mine

Originally Posted by Tentman

Nicely thought out project. Do keep us posted on its performance!

Cheers Mate

The reality is that I had this old T3 .223 and really wanted to shoot the Hornady 80gn eldm’s after reading all about their greatness in the .223 Thread on this forum.
Well after many rounds down range and a bit of expense, they shot no where near the accuracy of the the Sierra 77gn TMK’s that my Howa 1500 is capable of .
The Howa is handicapped by magazine length, but with the Waters Magazine the Tikka can use the longer / sleeker Hornady 80’s seated out long ….. But they didn’t shoot no matter what I tried .
My thoughts were to just get rid of the Tikka because I already had to many .223’s .
Then I read an article about the 6x45 and the brain started whirling.
I basically had everything needed to maximise the 6x45 cartridge ( having to load them short OAL is a real performance killer ) except for a barrel and a set of Dies .
The rest is history

This story isn’t all “ Blow Jobs and Party Pies “ though, I haven’t shot it yet , and the weather here means it won’t be for another week or so .
It might be another great big piece of “ Poo “ , but I have Sierra 85gn hpbt and Hornady 87gn hpbt projectiles to play with as well as 2206H , Benchmark, 2208 powders , CCi 400 , 450 , Br4 primers and Lapua / Starline / Fiocchi Brass .
Somewhere in amongst all of those combinations hopefully there will be an answer.

Originally Posted by sportco62

I shoot Sierra 70gr hp projectiles out of mine

How do they shoot ?
Do you know a velocity?
What barrel twist are you using?
How do you rate the chambering compared to the standard.223 ?
When comparing the 6x45 and the .223 research has shown that the 6x45 will have a slightly higher velocity when comparing the same bullet weights due to the efficiency of the larger bore/ case size scenario.

The only reason I contemplated the 6x45 is because in theory it can throw an 80gn plus projectile efficiently and effectively.
I already have a Howa .223 that shoots 77gn TMK bullets and lighter into small groups .
This is an experiment of how much of a bigger projectile weight can I practically use ( my threshold is 2700fps ) out of a .223 case / Rifle.

I have had 6.5TCU chambered rifle for years ( 6.5-223 Improved if you prefer) as I also have heaps of once fired .223 brass
a good charge of Power Pro Varmint or 8208XBR throws a 123sst @ 2500fps + so I would expect you would get faster velocity with the 6mm bullets.

You guys are far too technical for me . My one has a Mini mauser action , a Kimber of Oregon barrel , chambering done by Nelson Collie , laminated stock fitted by an old guy in Helensville - all done years ago.

Seriously - I dont recall any of that load information beyond "I loaded a bunch of rounds , found the ones that shot most accurately . and just stuck with those"

Sorry - I have way too many rifles , and too much load data to wade through to find any of it. But it shoots minute of goat and minute of fallow deer and thats all I need

My 23" 1:10 6x45 chucks out Sierra 85gr HPBT @ 2918fps using CFE223.
Same load in my 20" 1:8 6x45 does 2834fps. The CFE223 is the slowest powder I've used and most suited to 80gr + bullets.
I regularly run 75gr Sierra HP with H335 for about 3000fps in the 20" rifle.

By having a longer throat you'll achieve pretty much the same velocity but burn more powder to do it. This I have proven in another caliber. A long throat is great for those 80gr+ bullets when using something like CFE223, as it's a high density load.

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