German rifle production and rechambering of captured rifles

I stand corrected.
However:
" The conversion was a success from a usability standpoint but that was not enough. Cost and machine time were just too high and the 7.5mm Lebel was dropped. Instead, efforts were focused on adapting the Berthier since it already featured a vertical magazine design. Surplus Lebels did continue to receive attention through the adoption of the Mle.1886 M93 R35 which was simply a rifle shortened into a carbine, still in 8x50mmR. When Germany invaded the small number of M27 rifles saw service in the scramble for small arms."

Fitting a new, mauser style, magazine to the existing 1886 action was not cheap.

Never said it was a good idea.
But historical fascinating for the rifle fan.
Remember if you find squillions of rifles with ammunition then that means your industry doesn't have to build it so it's a win win. Even a Mosin is better than no rifle at all.

Shortround6 said:

In the case of the No 4 MK I they needed new barrels. The 7.62mm bing a few thousandths smaller than the .303.

For the rest of it you are basically correct. The Germans did pick up production facilities in Czechoslovakia and perhaps Poland for Mauser rifles. The Hungarians converted their rifles to 7.9x57mm. In many cases 2nd line troops got captured rifles.

Re-chambering only works if the barrel diameter is correct for the bullet you want to use and is fairly quick and easy. It also helps a LOT if the new round in larger than than the old one in body diameter and length.

For instance the Russian 7.62 X 54 R is actually larger in diameter down the body than either the 7.62 NATO or the German 7.9 X 57.

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Re-boring the length of the barrel can be done but is a lot more work than just re-chambering.

And then you have find out if the new cartridge will feed from the old magazine or if you are making single shot rifles. The length and taper of the new round have to match the angles of the feed lips of the old magazine or you get a lot of jams. (lips can be re-machined but that is more work).

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You make a good point. I believe that all 7.62x whatever length in mm- gives a NBD of .308"-- The British .303 has a NBD of .311"- .003" greater, but still a .30 caliber. Overall length of case, developed angle at the shoulder, and the rim or rimless (even the belted .30cal. Magnum series) all have their individual characteristics--I have a neighbor who is an avid varmint and target shooter, reloads quite a few popular calibers, and has taught me a great deal about rifle ballistics, both in his reloading den, and also on the rifle range. One question comes to mind, when re-boring and re-chambering a rifle barrel-- how does the rate of twist affect this procedure? Thanks, and I have learned a lot from your replies..

If you rebore you drill and ream the barrel to a larger size and take out all the old rifling. Then you cut new rifling to whatever twist you want (or your available tooling allows). Obviously this is labor intensive procedure. You also have to be careful that you don't overheat the barrel or otherwise cause stress that could result in the barrel "bending". Regular barrels are drilled, bored, reamed and rifled from a an over sized rod of steel.

once rifled they turned to the desired outside contour, threaded for the appropriate action and rough chambered. depending on procedure, action type and cartridge finish chambering is done once the nearly finished barrel is fastened into the action. Please note there is plenty of "meat" to help withstand the stress of drilling, boring and rifling. I would also note that most rifle factories had barrel straightening machines.

A few skilled, experienced workers could bend barrels to make them straight when nearly done.

When you rechamber that is usually the only part of the barrel that is touched (although recrowning may be done) , you cut a bigger chamber that the barrel was originally manufactured with.

Times and labor costs change. At one time it was somewhat common to have a well used rifle with a shot out throat "rechambered" to bring it back into spec. The gunsmith (or home machinist) took the barrel off, cut one or two threads off, cut a new shoulder on the barrel and cut one or two new turns of thread. The barrel was reinstalled and a chambering reamer cut the shortened chamber back to full length and hopefully this move the start of the rifling that much closer to the chamber, restoring accuracy.
I hope I have explained that correctly and at least somewhat clearly.
This has fallen out of favor as you don't really get a new barrel or barrel surface in front of the chamber. The rifling is a bit worn or at least rounded off and you have microscopic cracks or checks in the surface of the steel from thousands of shots that aren't there on a new barrel. This "rechambering" job won't have the same life (number of shots fired) before accuracy falls of again. If you are paying modern gunsmith labor prices and not doing the work yourself the labor cost of this "repair" is about the same as fitting a new barrel. And if the new barrel lasts twice as long then the cost per shot in barrel wear comes out about the same. New barrel lasts 5000 shots while the "rechamber" lasts 2500 rounds for example.

recrowning is taking a skim cut across the muzzle to eliminate any defects (dents/burrs) and then chamfering the ends of the rifling, this depends on the gunsmiths and customers beliefs are there are several schools and techniques

If you are rechambering a rifle to a different cartridge (larger case) you are stuck with the rifling in the existing barrel. A lot of times this is no big deal but in some cases it leads to restricted bullet choices.