I was dreaming....6mm TCU

[Okbow87]

I was thinking about this the other day after reading about a member on here who had his howa mini action bolt opened up and built a 6mm br. I started thinking about what could be built without having to modify the bolt on a howa mini with what they offer now and one of the more interesting options I came up with is pretty similar to your TCU idea.

There is a new ar-15 round out called the 6mm MAX, which is essentially a necked down 350 legend. It has 35 grains of h20 capacity vs 34 in the 6mm ARC, and right now its designed to fit into short AR style mags. Switching the howa mini over to Jeffersonoutdoors bdl style bottom metal gets you mag space to 2.46", which would allow a guy to throat it out a touch and probably pick up a bit more performance. I don't think the Jefferson mag box/follower currently works with 350 legend though, but I'm sure its coming. Plus all the load data available for it right now is only for gas guns. I believe starline is who produces the brass for the company that developed the cartridge. If a guy could get the bottom metal worked out it would be a pretty easy way to get that 6br level performance in that mini action without having to open the bolt face and have the firing pin hole bushed like the other guy here did to his.

 

[83cj-7]

What COAL were/are you loading the Vmax at?

Right now both of my rifles are running the HS Precision magazines so I’m loading them at 2.450”.
I’ve had a couple Tikka builds that I modified the mags to run 2.7”.

 

[Bert01]

Who did the work?

I’m doing the work for @KyleR1985, I’d be happy to answer any questions or pm.

 

[KyleR1985]

I was thinking about this the other day after reading about a member on here who had his howa mini action bolt opened up and built a 6mm br. I started thinking about what could be built without having to modify the bolt on a howa mini with what they offer now and one of the more interesting options I came up with is pretty similar to your TCU idea.

There is a new ar-15 round out called the 6mm MAX, which is essentially a necked down 350 legend. It has 35 grains of h20 capacity vs 34 in the 6mm ARC, and right now its designed to fit into short AR style mags. Switching the howa mini over to Jeffersonoutdoors bdl style bottom metal gets you mag space to 2.46", which would allow a guy to throat it out a touch and probably pick up a bit more performance. I don't think the Jefferson mag box/follower currently works with 350 legend though, but I'm sure its coming. Plus all the load data available for it right now is only for gas guns. I believe starline is who produces the brass for the company that developed the cartridge. If a guy could get the bottom metal worked out it would be a pretty easy way to get that 6br level performance in that mini action without having to open the bolt face and have the firing pin hole bushed like the other guy here did to his.

They don’t sell or rent a reamer.

They only sell gasser barrels.

Brass only available through them or you’re doing a lot of work to make it.



Those 3 things change it becomes pretty interesting. Until then there’s not a big enough gap in performance between 6x45 and 6ARC to justify it. But that may be because I haven’t found the project to make it make sense.


Loading the 6x45 is as easy and cheap as loading for .223.

 

[Okbow87]

Yes there are def a few hurdles, but I’m sure all of that will ease with time. I did see on carbon 6 barrels website they have the 6mm max listed as an available chambering in their prefits.

 

[WyoJeff]

yup....more about the handi!
anyone know who would rebore a 223 handi to the 6x45?

 

[KyleR1985]

yup....more about the handi!
anyone know who would rebore a 223 handi to the 6x45?

Wayne York at Oregunsmith will rebore a .223 to 6x45.



I opted not to go thay route for a few small reasons. Main one was the ability to swap in new barrel pretty easily. We kept the extractor setup on the breech intact. Just bored and threaded in front of it. Just chamber the new barrel short, or do what Bert and I did and use an AR barrel.

If this barrel doesn’t shoot well (it’s a Satern 6x45 20”), I have a Shaw portless .223 wylde pencil barrel on a non gassed AR I can swap in.

If you want to know about handi rifles, graybeard forums is the place to be.

Happy to answer any questions too

 

[Moose83]

Wayne York at Oregunsmith will rebore a .223 to 6x45.



I opted not to go thay route for a few small reasons. Main one was the ability to swap in new barrel pretty easily. We kept the extractor setup on the breech intact. Just bored and threaded in front of it. Just chamber the new barrel short, or do what Bert and I did and use an AR barrel.

If this barrel doesn’t shoot well (it’s a Satern 6x45 20”), I have a Shaw portless .223 wylde pencil barrel on a non gassed AR I can swap in.

If you want to know about handi rifles, graybeard forums is the place to be.

Happy to answer any questions too

Have any pics of the rifle open and the chamber and extractor? Trying to picture how this barrel stub process works. Also do you have a weight on this thing?

 

[KyleR1985]

Have any pics of the rifle open and the chamber and extractor? Trying to picture how this barrel stub process works. Also do you have a weight on this thing?

I’ll get more pictures when I have hands on the rifle.

But it’s bored and threaded from the front of the handi stub to accept the barrel. In this case it’s an AR barrel thread(the threads on OD of barrel, inside the barrel extension - which was removed)

Drop a bullet in a loose AR barrel and look at back of case - it sticks out about 1/4” or so into the barrel extension for the AR bolt to lock onto it. Works perfect for what I’m doing here.

We left a shoulder inside the handi stub where the back of the AR barrel lands. Which left the extractor in place. In essence, the rear 1/4” of the chamber is the handi stub barrel, and the remainder of the chamber is the AR barrel. Headspacing accomplished by taking face off the AR barrel(and Bert being good at this shit).

I didn’t want to mess with building extractors and cutting extractor grooves.

If you looked at the back of the handi barrel it would look exactly like it did before this modification. That’s the idea. Lugs, extractor, etc. all remain in place and functional.

thay make sense?

 

[Moose83]

I’ll get more pictures when I have hands on the rifle.

But it’s bored and threaded from the front of the handi stub to accept the barrel. In this case it’s an AR barrel thread(the threads on OD of barrel, inside the barrel extension - which was removed)

Drop a bullet in a loose AR barrel and look at back of case - it sticks out about 1/4” or so into the barrel extension for the AR bolt to lock onto it. Works perfect for what I’m doing here.

We left a shoulder inside the handi stub where the back of the AR barrel lands. Which left the extractor in place. In essence, the rear 1/4” of the chamber is the handi stub barrel, and the remainder of the chamber is the AR barrel. Headspacing accomplished by taking face off the AR barrel(and Bert being good at this shit).

I didn’t want to mess with building extractors and cutting extractor grooves.

If you looked at the back of the handi barrel it would look exactly like it did before this modification. That’s the idea. Lugs, extractor, etc. all remain in place and functional.

thay make sense?

Kind of makes sense... I am Canadian though so I'm very unfamiliar with AR's and how they work... lol, so I'll just wait until you have time to post up pics. Maybe you could start a thread on this rifle as well, there seems to be a lot of interest in it... then we don't have to derail the OP's thread anymore!