6mm Conundrum

[Bramley Futter]

Good day Gentlemen
I have joined this site, because I have got very good info over the years, by being directed here when googling gun info. I have found this site to be most informative & helpful. I have a dilemma that I need advice on, from members and/or gunsmiths on this group.
I have an original issue Sako .222 Rem. This rifle was given to my by my father, for my 9th birthday. I started my game hunting career with this little beauty & have loved it ever since. I since bought a matching .22 LR, which I enjoy equally. I bought a matching .222 from a deceased estate, with the idea of converting it to 6x45, so that all my baby rifles would match. My problem is this;

My rifle is an original Sako L46, which was designed & made as a .222 Rem. The action is too short to accommodate the standard 6x45 or ,223 Rem. cartridges. To make this a 6x45 will entail costly modifications to the action, magazine & magazine well. My idea is this;

The .223 Rem case length is 2mm longer than the .222. Would it be possible for a gunsmith to stop the 6x45 chamber reamer 2mm short, when reaming the chamber? This would give me a cartridge with a neck the same length as the .223/6x45, but the case length of the .222. It would give me the powder capacity to approximate the 6x45 ballistics, in a cartridge that would work in my rifle. I would make my own case by modifying .223 cases.
Any advice would be greatly appreciated.

 

[Bramley Futter]

I've copied my original thread from the General forum, hoping some of you 'smiths can advise me.

 

[Roeder]

This may prove to be more difficult than it sounds. 6mm bullets are longer, even the shortest 55 and 58 grain ones. The 6X45 rifles that I have done on standard Remington actions with the blocked .223 magazine needed a little more magazine length than the standard magazine and I ended up making a thinner block for the back of the magazine box to allow for it. So even reducing the chamber by 2 mm might not be enough to get your loaded 6mm rounds to fit the magazine box. A good starting point would be to make up some dummy rounds and see how they compare to you available magazine length.

As to running the 6X45 reamer in 2mm short (about .080), this would result in a chamber about .0015 tighter than the full depth which may or may not be an issue depending on the actual brass and size die dimensions.

There are guys that do this kind of wildcat job all the time and probably more that avoid doing it because of the pitfalls. The typical 6X45 chamber has about .050 freebore which is more than is needed for the light bullets. So you could be looking at a custom reamer, a custom size die, plus the extra labor to form the cases etc.

If you are happy with the result it might be worth it. Only you can decide that.

 

[Bramley Futter]

Thank you Roeder, for your informative reply.
I live in South Africa, so our gunsmiths would not have any chamber reamers for the more exotic rounds. I only intend to shoot 70-80gr bullets in the rifle, max. If I want 100grs, I'll use my 6mm Musgrave (.303 Br necked down to .243). I would need to get a custom reamer from someone like Pacific tool & Gauge.
Just a question; If I go the custom reamer way, what about a straight-walled cartridge, without the taper, like the Ackley Improved cartridges? Would this not negate the problems you described (they seem to be related to case taper)? This would also help out my case capacity issue, by adding slightly more capacity. I could then fire-form standard .222 cases.

 

[Roeder]

Thank you Roeder, for your informative reply.
I live in South Africa, so our gunsmiths would not have any chamber reamers for the more exotic rounds. I only intend to shoot 70-80gr bullets in the rifle, max. If I want 100grs, I'll use my 6mm Musgrave (.303 Br necked down to .243). I would need to get a custom reamer from someone like Pacific tool & Gauge.
Just a question; If I go the custom reamer way, what about a straight-walled cartridge, without the taper, like the Ackley Improved cartridges? Would this not negate the problems you described (they seem to be related to case taper)? This would also help out my case capacity issue, by adding slightly more capacity. I could then fire-form standard .222 cases.

If you do order a custom reamer, you can specify the exact dimensions you need to match your size die. The chamber needs to be about .003 smaller than the die. You can design a .222-6mm or 222-6mm Ackley. The length of your loaded rounds with 80 grain bullets may still be too long for your magazine unless you seat the bullets with the base deeper than the neck shoulder junction.
What is the longest cartridge length your magazine can accommodate?

 

[butchlambert]

Man, I wouldn't do it on a L46. I would keep it as is and buy another rifle to modify.

 

[Ggmac]

You could always use a 221 case opened up and run deep .