Barrel shroud...?

[NORZ]

A couple of threads below re-contouring a barrel was mentioned. I have a 308 with a fairly heavy barrel measuring 19mm at muzzle and 30mm at chamber. I was planning to turn the barrel down to 17-18mm until the full 30mm at the chamber end.

Anyways. This has more than likely been done before, attempted or at least thought of! The plan is to install a 7075 aluminum tube that is 30mm OD and 0.5-1.0mm under turned barrel OD. The tube has 4 shallow spiral flutes. The plan is to get the barrel very rigid, to dissipate heat and for the heck of it.

So, anyone?

 

[Robert]

A couple of threads below re-contouring a barrel was mentioned. I have a 308 with a fairly heavy barrel measuring 19mm at muzzle and 30mm at chamber. I was planning to turn the barrel down to 17-18mm until the full 30mm at the chamber end.

Anyways. This has more than likely been done before, attempted or at least thought of! The plan is to install a 7075 aluminum tube that is 30mm OD and 0.5-1.0mm under turned barrel OD. The tube has 4 shallow spiral flutes. The plan is to get the barrel very rigid, to dissipate heat and for the heck of it.

So, anyone?

NorZ,

At 19mm at the muzzle and 30mm at the shoulder, a match barrel is already fairly light...

The system you are looking is as old as the german 1888 Komission rifle.... but this one was in steel..

Have you had any thoughts about the heat expansion differential of steel and aluminium over that lenght??

R.G.C.

 

[NORZ]

I have put some thought into heat expansion therefor the tight fit. According to my calculations this fit should do it, if the heat would stay within 250°C. The flutes at 3 times the surface area, that in it self, plus the thermal conductivity of 7075,expansion-rate) is,'again' is enough according to my calculations. The stainless steel barrel surface will be coated with Mastinox for corrosion and heat transfer.

This is something that I have been tinkering with for a long time. Getting the barrel extremely rigid. Not necessarily for heat dissipation.

Been on a thinking rampage this summer

 

[Tozguy]

Been thinking about doing the same thing for a while now just out of curiousity. An aluminum covered steel barrel by Majestic Arms is what got me excited. It must be highly technical to do it right. I wonder if they use a press fit, shrink fit or other means to join the two pipes. Bore and rifling might be cut AFTER assembly. For the DIY approach, my first inclination would be to shrink fit the aluminum tube over the steel barrel and hope that bore & groove dimensions don't change.
As a hedge against different thermal expansion rates of steel versus aluminum, I would cut the barrel as short as feasible.