FAL .308 to .338?

[Tomcat088]

it is a pita to recut a bore, but not as bad as one would really think, lol.

I don't know who told you that it wasn't that bad, but whoever did is mistaken. It's not all that difficult to recut a chamber if you have the proper tools. Recutting a bore is a different animal all together. Most people don't have the proper machines to run the button in the first place. Then because the metal expands and moves, you'd have to probably recontour the barrel and cut it off to proper length. You'd also need to stress relieve the barrel if you wanted it to shoot worth a dang. Cut rifling is a different process, but there aren't too many people that have machines set up to do it, including some of the top barrel makers. I'm sorry, but I disagree, recutting a bore to a larger size is every bit as bad as some people think, and worse.

[digdug18]

I don't know who told you that it wasn't that bad, but whoever did is mistaken. It's not all that difficult to recut a chamber if you have the proper tools. Recutting a bore is a different animal all together. Most people don't have the proper machines to run the button in the first place. Then because the metal expands and moves, you'd have to probably recontour the barrel and cut it off to proper length. You'd also need to stress relieve the barrel if you wanted it to shoot worth a dang. Cut rifling is a different process, but there aren't too many people that have machines set up to do it, including some of the top barrel makers. I'm sorry, but I disagree, recutting a bore to a larger size is every bit as bad as some people think, and worse.

I have done both, and re-cutting a bore with the proper machine is easier then you might think. I think the biggest pain really is taking the barrel off, the putting it back on and headspacing it. Sorry you really don't need to stress relieve the barrel, and if you did it too is an easy process. As for cutting the rifling, you really shouldn't have to when going from .308 to .338, the rifling grooves are deeper then you think. Though it is possible that the barrel will wear out faster, as well as need to be cleaned more often.

[gold cup abuser]

Another thing to think about on the FAL platform....

IF you can get the barrel to the new chamber diamater and rebore a GI surplus barrel then you might have other issues to review/resolve.

1. Cartridge length. I am not in front of a reloading book, but I do belive there is a potential cartridge size issue in using the 338 Lapua round. I do not belive the reciever would be large enough to handle that round.

2. Magazines. Again with the size issue, there is going to be an issue with either making the current magazine function with the 338 Lapua round, or find a way to fabricate a magazine that will:

a. Fit the cartridge.
b. Fit the receiver.

3. There is also a flex issue with the FAL platform. The lower receiver is not rigid enough to provide a platform allowing the 338 Lapua round to get the best accuracy possible from that round. Also, the repeatablity of having the bolt and bolt carrier allign conistantly shot to shot is another variable in getting sub MOA groups.

4. Flex of the platform is also going to be aggravated by the scope mounting point. With all of that metal from the bolt and bolt carrier moving around it will transfer tha movement to the upper receiver cover. Even if you are using one of the new rigid upper receiver covers that will allow a scope to mount, the flexing of the internals, and flexing at the 338 Lapua level would either not allow a conistant scope zero, or damage the scope.


An interesting alternative to up caliber of the FAL would be to consider downsizing....

Oh say....270 Winchester or 6.5x47 Lapua

might be a better spend of ones time and cash on those two rounds

[Tomcat088]

I have done both, and re-cutting a bore with the proper machine is easier then you might think. I think the biggest pain really is taking the barrel off, the putting it back on and headspacing it. Sorry you really don't need to stress relieve the barrel, and if you did it too is an easy process. As for cutting the rifling, you really shouldn't have to when going from .308 to .338, the rifling grooves are deeper then you think. Though it is possible that the barrel will wear out faster, as well as need to be cleaned more often.

Do you really have a clue what we're talking about here? The reason I ask is because some of the stuff that you've said really has me wondering if you do.

You're right, IF you have the proper machine, you can recut a bore fairly easy. That being said, it's not like you can just throw it in the lathe or mill and recut the bore. You realize we're talking about the entire bore down the length of the barrel, not just the crown?

Something that you say in your post that has me confused is you say, "the rifling grooves are deeper than you think". Hmmm, that's interesting, because I assure you that the GROOVES are not deeper than I think. You see, in a .308 caliber firearm, the .308" IS THE GROOVE DIMENSIONS. The LAND dimensions will vary, but are usually somewhere around .300", although some variations of this do exist in barrels made for palma bullets, etc. So hate to break it to you, but NO, the grooves do not go deeper than I think, and they better be spot on or dang close to .308".

If you aren't stress relieving a barrel, then that means you're likely not doing it with a button. Button rifling puts GREAT amounts of stress on a barrel. If you're doing cut rifling, it requires a special machine, and a great deal of time. Proper stress relieving is NOT an easy process. If you're using heat, the temperature has to be perfect and maintained for a certain amount of time. Then you have to control the rate that it cools down, and it needs to be watched pretty closely. If you're going to cryo the barrel, then it has to get extremely cold, and maintained at that temperature for long enough. Either way, it's not something that the average joe, or even the average machinest can or needs to be doing.

You HAVE to recut the bore, which includes the lands (rifling) and the grooves. You say that you don't have to recut the rifling, and to think otherwise is silly. First things first, I would NOT advise someone try to shoot a .338 bullet down a .308 bore. Swaging the bullet down to a diameter that would go down the barrel would build TREMENDOUS pressure. High pressure is the LAST THING you want on a gas operated firearm, especially one with a piston/op rod design. It's a good way to take an op rod to the head and DIE. Even if the rifle didn't grenade, the bullet would be so long when it exited the barrel that the accuracy would be horrible. Ok, so we've established that at least the grooves have to be recut. This means that the barrel would have a groove diameter of .338, which is good so that the bullet doesn't have to be swaged down.

IF you wanted to recut the bore diameter to .338 without recutting the lands, it would requite a special button. The reason being that the button or buttons, depending on if you first swedge the diameter to slightly oversize, and then finish it and press in the button, or if you just make a pass with one that does both. The process that you're talking about would mean that you can't just press out the diameter first because that would get rid of the rifling, so you're talking about a process that does NOT do this. This means you'd have to have a button that would LEAVE the rifling in the barrel, and only press out the bore diameter, and add just a little bit to the existing rifling. To do this, you'd need a custom button that EXACTLY matched the rifling width and shape already in the rifle, then it would need to be the diameter of .338, and have the button made so that it would pretty in the extra rifling to make the rifling meet the bore. So do you have one of these custom buttons, or know exactly where a smith can get one of these buttons? How much do they cost? Machining tools are not cheap, and a custom button would be no exception.

So let's play along, and pretend that you can get a custom button that will do this. Well, there's other problems that will come with this technique. Now that you've enlarged the bore diameter, but haven't cut the rifling down any, the lands are going to be LONGER, and they're going to cut deeper in the bullet. This means that you're cutting grooves into a .338 diameter bullet that are .300" deep. The reason they're .300" deep is because you said never touch the rifling, so they are at the previous dimensions which are .300". You do NOT want to be cutting .019" ON EACH SIDE of the bullet. Normal rifling only cuts about .004" on each side of the bullet. Cutting this deep into a bullet would cause all kinds of problems. The first one being that the bullet might not make it down the barrel from all the friction, and could cause all the same problems of attempting to swage a bullet down. The bullet might make it down the barrel, it might not, I don't know for sure and don't care to find out. So let's say that you could get the bullet to exit the barrel, there are still some other problems too. The jackets on bullets are NOT typically .019" thick, so when you cut that deep into a bullet, you've usually already cut through the jacket. If you cut all the way through the jacket of the bullet, it WILL seperate from the rest of the bullet. Jacket seperation in bullets does NOT lend to accuracy, penetration, or any other desirable effects. So again, there is not much of a way or reason to cut the bore and not the grooves, it won't work right.

Even if you could cut the barrel, and stress relieve it, which you say we don't need to do; something else becomes a problem. After you run a button through a barrel, you're going to have burrs. So are you good at fire lapping and finish lapping a barrel? With all the time you apparently have spent to perfect these skills, why aren't you making top tier barrels or at least working as a lapper for them? After all this type of work, I'd think that you wouldn't think that removing a barrel and headspacing it to be that big of a deal. If you're not going through all that trouble, then it means your cut rifling the barrel. If you are, it means you have a very expensive and rare machine for cut rifling. If that's the case, again, why aren't you making custom barrels and making a lot of money? Do you have machines that are anything like these http://riflemansjournal.blogspot.com...ed-barrel.html .

So I'm curious, exactly how is it that you're recutting the bore on the barrel that is so easy? I don't doubt that it's not "easier" with the right machine, I just know what kind of machine it takes and how many people typically have those. So what kind of rifling or buttoning machine do you have? If so, why are you just doing this on the side and taking the time to work on an FAL barrel instead of just making a new one really quick? I'm eagerly waiting to hear how you do it. If you would, can you also answer how you get around some of the issues that I've mentioned, seeing as how you have to be able to do it some way. Thanks

[justashooter]

the FAL is a great platform to convert to special use cartridges. it has been converted to everything in the 30 nato family from 22-250 to 243 to 7-08 to 338 fed to 358 win, which is the king for heavy stuff. it has been converted to various 6mm stuff and even to 8X57, 30 AK, 300 savage (why?) and 45 ACP. if you wanna learn more about this register at the FALFILES Forum and ask in the gunsmithing section. Meeper even produced a switch barrel system at one time.

as for cutting a .308 bore to .338, that's more trouble than it's worth. just get a blank in the bore you desire and have it cut to FAL profile and it's a drop in, assuming that your case is similar enuf to reliably feed from the magazine.

[Warpt762x39]

as for cutting a .308 bore to .338, that's more trouble than it's worth. just get a blank in the bore you desire and have it cut to FAL profile and it's a drop in, assuming that your case is similar enuf to reliably feed from the magazine.

The .338 Federal is just a necked up .308. The body dimensions are the same.

[justashooter]

The .338 Federal is just a necked up .308. The body dimensions are the same.

it does, however, shoot a bullet that is 30 thou larger in diameter. to modify a 308 bore to 338 is either tedious or sophisticated work. i know one guy in york county that has the right equipment to do it, and his machine is not running. a new machine to do it right is $200,000. even if you did it the hard way, and got finished next year, you would have over $200 in piloted drills and reamers, much less the value of whatever rifling cutter you cobbled together.

FAL barrels have a BHN of about 190. they are not blackpowder guns made of butter. you do not want to try to rebore one with hand tools.

[Warpt762x39]

it does, however, shoot a bullet that is 30 thou larger in diameter. to modify a 308 bore to 338 is either tedious or sophisticated work. i know one guy in york county that has the right equipment to do it, and his machine is not running. a new machine to do it right is $200,000. even if you did it the hard way, and got finished next year, you would have over $200 in piloted drills and reamers, much less the value of whatever rifling cutter you cobbled together.

FAL barrels have a BHN of about 190. they are not blackpowder guns made of butter. you do not want to try to rebore one with hand tools.

I was referring to the feeding from the magazine part you mentioned. The magazine and bolt face won't need to be changed. Just the barrel. It's like rechambering a 5.56x45mm AR to the recently standardized 6x45mm. Only change needed is the barrel.

[justashooter]

may need to modify the feed rails and magazine feed lips on an FAL converted from 308 to 338 federal. different bullet diameter so diffirent interaction with feed lips.

[Warpt762x39]

may need to modify the feed rails and magazine feed lips on an FAL converted from 308 to 338 federal. different bullet diameter so diffirent interaction with feed lips.

Nothing behind the neck of the case touches the feed lips on the magazine. It only contacts the case body itself which does not change between the calibers.