Thread: Rechambering a .243 to .308 how hard?

A WTS thread for a Remington Mohawk in .243 got me thinking. How hard would it be and what would be involved in rechambering a rifle like that from .243 to .308? I know you could have the barrel rebored and rifled for .308, but I am not sure what concerns you would have about headspace issues as the .308 headspaces on the shoulder as does the .243. Has anybody ever done this? If so, how did you do it?

Should be pretty straightforward with no forseen problems. Headspace gauges are the same for all the .308 based calibers - so you are really only looking at the bore and not the chamber.

Originally Posted by MilesTeg

Should be pretty straightforward with no forseen problems. Headspace gauges are the same for all the .308 based calibers - so you are really only looking at the bore and not the chamber.

I just wasn't sure it was that simple. Is the angle of the shoulder of the case the same for .308 as it is for .243? If that's the case, you are right, but I thought the shoulder angle was different.

Yes, the shoulder angle is 20 degrees for all the .308 based rounds. Take a look at the 7mm-08 as well. I think you will like what you see when you compare the ballistics. If you don't reload, however, it might not be the best round to go to as there are more factory choices in .308.

Shoulder angle is the same for .243 and .308 at 20 degrees per side or a total of 40 degrees.

The dimensions are close. But the cost of rechambering,reboring, and rerifling are going to far exceed the cost of buying a .308 barrel and having it fit to the receiver.

Originally Posted by MilesTeg

Yes, the shoulder angle is 20 degrees for all the .308 based rounds. Take a look at the 7mm-08 as well. I think you will like what you see when you compare the ballistics. If you don't reload, however, it might not be the best round to go to as there are more factory choices in .308.

Thanks, I was looking at .308 as I already have another rifle chambered in .308 and have been trying to consolidate calibers as much as possible. Any idea what a competent gunsmith would charge to rebore a rifle? Trying to decide if it would make sense economically or if I should just look for a rifle originally chambered in .308.

Originally Posted by Cougfan2

Thanks, I was looking at .308 as I already have another rifle chambered in .308 and have been trying to consolidate calibers as much as possible. Any idea what a competent gunsmith would charge to rebore a rifle? Trying to decide if it would make sense economically or if I should just look for a rifle originally chambered in .308.

PM sent

Thanks, Gunner. I think you just answered my question to Milesteg.

I was just thinking about this today myself. I have an old 721 in .270 i was thinking about changing the caliber as well.

What was the answer Cougar?

Originally Posted by Cougfan2

Thanks, I was looking at .308 as I already have another rifle chambered in .308 and have been trying to consolidate calibers as much as possible. Any idea what a competent gunsmith would charge to rebore a rifle? Trying to decide if it would make sense economically or if I should just look for a rifle originally chambered in .308.

My advice is to NOT rebore the rifle, but buy a new barrel in .308 and a barrel wrench. One action, two rifles for all intents and purposes. My guess is a local outfit like Pac-Nor probably has what you need ready to ship.

Originally Posted by 2506

My advice is to NOT rebore the rifle, but buy a new barrel in .308 and a barrel wrench. One action, two rifles for all intents and purposes. My guess is a local outfit like Pac-Nor probably has what you need ready to ship.

That's a poor idea unless you are going to be using a barrel nut system like on a Savage. Torquing a barrel on and the taking it off will swage the metal on the barrel shoulder, advancing the headspace a thousandth of an inch or so every time you pull it on and take it off. Eventually that will blow your headspace. Not a good idea.

It should cost you a few hundred bucks for a new barrel and around a hundred and a half to have the new barrel installed on your action. This is not a do it yourself project. Hire a pro...

Savage FTW!

Routinely swap betweem 22-250, 7mm-08 and 338 Federal..

Let me clarify. I dislike Savage a lot. The barrel nut is aesthetically ugly as sin, and I don't like the bolt. But the barrel nut does offer a good bit of versatility in changing calibers (which I generally find to be a poor idea for non-gunsmiths, sorry to all you tinkerers, but...).

LOL, it is ugly but very accurate and that spins my world. I like Remchesters as well - mainly the ones made in the early 70's.

Originally Posted by MountainBear

Let me clarify. I dislike Savage a lot. The barrel nut is aesthetically ugly as sin, and I don't like the bolt. But the barrel nut does offer a good bit of versatility in changing calibers (which I generally find to be a poor idea for non-gunsmiths, sorry to all you tinkerers, but...).

You can check out Jesse Ocumpaugh, down in the Cottage Grove area.
Home - Reboring by J E S
He bores .223 and up.
Prices, etc on his website.

If you simply re-bore a barrel you must rechamber also as the neck and lead/leade must be cut into the chamber as well.
If you just re-bore there will be rifling where the cartridge neck should be.

I have seen Jesse's work and you will be very happy. He is as cheap as anyone and cheaper than some for his re-bore work. I'm thinking of having him rebore a Ruger 300 Win. Mag. to .375" and chambering it to .357 Ruger.

Remember if you are going to re-bore a rifle to make sure you will be happy with the resulting wieght/contour/thickness of the barrel.

BTW, I love Savage 110 series rifles, the newer the better. I just build myself a 6.5mm WSM on one. I never would have considered a Savage for anything but a target/varmint rifle before but their newer detatchable magazine system and synthetic stocks have won me over. The Accu-Trigger ain't half bad for a big game rifle either. I'd have to go with a Sharpshooter on the varmint rifles though.

Since it seems it hasn't been said enough already... Why rebore? Boring is probably the easiest operation to screw up and yield one trashed barrel. I could see if somehow steel were expensive and labor was cheap.

You should be able to find a barrel blank, a takeoff barrel, or any other number of ways to get a barrel that is already .308 groove diameter and just has to be chambered (properly) to fit your action. I'm not a fan of switch barrel guns, but I have changed out barrels and found it to be a relatively straight-forward process. I imagine a take-off remmy 700 barrel should be availible on gunbroker as most of the people who buy PSS's strip off the barrel and put on a nice custom barrel.

The other reason i advocate replacement, is it is nearly impossible to get two chambers to line up after a process as involved as this is, you cannot simply cut the throat and the front end and expect your headspace to be ok, and everything to line up perfectly, a rebore is going to require a rechambering.

In defense of the savage.... I've had a savage model 10 for years, it's been a very accurate and dependable arm, sure it may not be as nice as a custom remington, but it didn't cost as much as a custom remington, and since it regularly outshoots custom remingtons I don't think I'm doing too bad. What sold me on the savage was being up at the range with a few of the old farts... One of them was shooting a .243 win savage model 10. We were playing a game of cards, he would show me a card, then I would have to hit the corresponding card and times were kept. Since I could, with a minimum of time on the gun, make a <.5" cloverleaf on the king's head at 100 yards I was more than sold on it. We can debate the technical aspects until the cows come home, but until a better rifle is availible at a competitive price, savage still is the best rifle for the money.

I'm glad I'm not the only one who doesn't think the 700 is as good as the 110. My 110 in 270 will outshoot my 700 in .06, any day!

I only have two Savage 110 series rifles and 4-5 Remington 721/722/700/7 series but I like the Savage better.