A little off track but ok. Out of the creat with all the same ammo
Not if it's a poor lot of ammo.
I have gone through several crates of different ammo. Everything from pre WWI surplus to 80s manufactured FN and Greek.
A few years back I had access to a couple of crates of Turk surplus. I put it through four rifles I knew weren't particularly fussy about ammo and shot everything put through them into 2 inches or less. The Martini and 1950 Long Branch are particularly accurate. The Turk surplus wouldn't shoot well in any of those rifles. It was all very pretty and bright but just wouldn't shoot well. I thought maybe velocities were to divergent but that wasn't the case. They all shot within 50fps. I even checked bullet diameters and weight all were acceptable. Then what I should have checked first, run out. It was acceptable as well. Nothing I could measure or see to indicate why this stuff was not accurate. It was built by the Turks to be used in every type of Lee Enfield/Enfield/Martini in their arsenals.
Now the Greek ammo and the South African ammo is lovely stuff and at worst, it is acceptable in every rifle I have shot it in. Some batches of UK and North American surplus are dreams and others are as bad or worse than the Turkish stuff. I had one batch, about 50 crates on a pallet that were all dated 1944 out of the US and they were loaded with .308 diameter projectiles. When I sold that stuff I told people about the bullet diameters but I never had anyone come back to me and complain.
Each rifle is an entity unto itself. If all is well such as purple suggested in the ways or barrel channels, butt stock tight, not filled with cosmoline, excellent bore that is close to the median specs they should be able to shoot acceptably. Like every other firearm out there, every once in a while all the stars align perfectly on your birthday and you find a Lee Enfield that doesn't care what you feed it as long as it is consistent, it will shoot nice tight groups.
Military surplus rifles are built to certain tolerances that will be subject to change depending upon the stresses of production at any given time will also effect how accurate any particular rifle will be. I have had new in wrap Long Lees, No 1s, No 4s and No 5s as well as P14s in just about every mark with bore dimensions that vary from .309 to a particularly large .318 in an Australian Lithgow No1.
The big thing is comparing a military surplus rifle to a modern commercial rifle for accuracy is like comparing bananas to crab apples. It is my understanding that No4 rifles were required to shoot groups of four inches or less at 100 yards with issued ammunition. Up until a decade or so ago, most commercially manufactured ammo was still built to similar specs as the ammo made in WWII. Maybe a bit tighter but not much.