To Rechamber or Not

[bme27]

So I have a Thompson/Center Icon chambered in their 30TC round. I have actually enjoyed the 30TC cartridge, but it can’t be reloaded to perform as well as the factory ammo. I feel this leaves me with two options: 1, buy a ton of factory ammo for it and sit on it or 2, rechamber the gun to a .308 or something else. I like the action and the gun well, but having the luxury of plenty of reloading components anywhere I go and factory ammo as a backup at any store that sells ammo are big draws.

How difficult would it be to get it rechambered to a different cartridge? I have never had a gun rechambered.

If I rechamber it, is the .308 the cartridge I should do or is there something else I should do? I should also say this is a backup hunting gun for mule deer and elk, but will primarily be used out at the range for fun.

Is there any other options I am missing? Thank you all in advance!

 

[Dave DeLaurant]

Sounds like you have two questions: should you rechamber, and if so to what.

With respect, I would never accept the statement that any cartridge "can’t be reloaded to perform as well as the factory ammo". With the right data and access to the proper components, a handloader can at least equal factory performance. The more relevant question IMO is whether this can be done in a time and cost effective manner -- I don't handload 5.56 NATO and 9x19 FMJ for the simple reason that the cost of cheap milspec factory ammo is practically the same as my component cost.

Now, to your question. A simple rechamber is a relatively cheap and quick gunsmithing job, provided the reamer is available. I've done it myself with break-open single shots and revolver chambers, but I prefer a gunsmith to handle the job on other types of actions. On some arms it is necessary or advisable to remove the barrel from the action to perform a precision rechamber job.

I would assume factory 30TC ammo is more expensive and less commonly available than .308 Winchester, so perhaps that would add to the rechambering argument. Here are some things to consider about a simple rechamber:

Will the new chamber completely 'clean out' the old one?

Is the twist rate and bore diameter of the rechambered cartridge compatible?

Will the action feed and function with the new cartridge dimensions?

The twist rate should be compatible for both cartridges, so that shouldn't be a problem.

Checking the action is a matter of taking a few dummy cartridges and seeing whether they feed smoothly. Usually you can expect some cartridge OAL limits when you change to a longer cartridge.

I checked the .30 TC case dimensions against .308 Winchester and the TC appears to be a bit fatter near the datum line. So a simple rechamber job may not be in the cards -- the barrel may also need to be set back slightly. Someone more familiar with both cartridges could confirm this.

Setting a barrel back a turn gets expensive and requires a competent gunsmith to 'retime' barrel rotation. That can get expensive fast. Rather than going through this, I personally would sell a rifle and buy a new one instead.

 

[Legionnaire]

Dave beat me to it. I don't think you can ream a 30TC to a .308. Cost wise, I agree you would likely be better off selling the rifle and buying another.

At the same time, I am interested in your statement that the 30TC cartridge "can’t be reloaded to perform as well as the factory ammo." Do you mean you have not been able to achieve the original's velocity, accuracy, or both? My understanding is that the 30TC has more horsepower than the .308, so you would give up power by rechambering (or rebarreling) in .308. I would think you should be able to find an accurate load with the power of the .308 in your 30TC. The least expensive solution would be to find an accurate hunting load of slightly less power than the 30TC; it should still top the .308. That's what I'd do in your situation.

 

[Legionnaire]

As an aside, the .30 TC was designed to outperform the .30-06. The 6.5 Creedmoor is a .30 TC case necked down to 6.5 mm. I wonder if the .30 TC would be more popular if it were renamed the ".30 Creedmoor?"

 

[someguy2800]

The problem is going to be that the 30 TC is almost a completely straight wall case, whereas most others have a significant taper, so it will not clean up rechambering to 308 unless you set the barrel back like an inch and a half which is not feasable. A complete rebarrel is the only option I see to get to 308. Does the difference in velocity you get from handloaded ammo really make or break the rifle? Would you be able to tell the difference without the chronograph?

 

[cougar1717]

I think reloading 30TC to equal or better accuracy than factory ammo could be done. However, with the factory ammo having the Superperformance technology (a case full of specialty ball powder)..... yeah..... the reloader probably can't hit the velocity numbers with off the shelf powder.

However, in this case, if you like the rifle and want to keep it as your hunting backup gun, just stock up on ammo.
But , If the desire is for more of a range fun rifle, I would just sell this to purchase that.

The biggest problem is that the ICON is discontinued - as in there are not many parts out there (like a take off barrel). I'm sure any barrel maker would love to make OP a barrel, but rebarreling is usually too expensive for the purpose of saving on ammo cost.

 

[Jim Watson]

If you are not getting factory load accuracy, rechambering is not likely to help.
If you are not getting factory load velocity, so what? Are you shooting at extreme long range?

 

[Legionnaire]

If you are not getting factory load velocity, so what? Are you shooting at extreme long range?

Exactly. And you won't improve on velocity by "downsizing" to a .308.

 

[jmr40]

If he isn't beating 308 performance with handloads, and the only other option is to use expensive factory ammo then going to 308 makes plenty of sense. Looking at 30TC load data all of my 308 loads match or beat anything listed. Hornadys factory loads only best 308 by about 100 fps. I'd dump the rifle in a heartbeat even at a loss.

the .30 TC was designed to outperform the .30-06.

Maybe 30-06 loads from the 1930's, but modern 30-06 loads will easily beat 30TC.

Exactly. And you won't improve on velocity by "downsizing" to a .308.

He won't give up anything either. But he will have a cheaper rifle to shoot with much more commonly available ammo and components. Probably better accuracy too.

 

[illinoisburt]

Common theme to most new gun/catridge combos we see every few years. If they don't take off, ammo becomes an issue. A lot of the short-fat magnums share the same fate. Best advice is sell and buy something more common if the ammo cost and availability are issues for you. Going through the expense and hassle of a conversion will likely not turn out better than a straight up swap. Plus there mau be someone else who really enjoys the chambering and would prefer to have it.

 

[bme27]

Thank you all for the replies and help! Sorry I haven’t responded quicker, life has been crazy. I think I’ll look into reloading for it, see what Hornady and Hodgedon have for the 30 TC and go from there. In the end I might end up with a Tikka or Savage to build off of and sell the 30 TC.