Anywho, The first thing I noticed is that the boxes I have are dated,  27 July 1941 Lot 316. The next item I attended to was to pull a bullet and check the powder situation. The powder looks brand new and scaled out at exactly 45.0grns. The cases are at 2.220" and the rim thickness is .0610" as well. The OAL is 3.025" on every round. The only data I can find that uses 45.0grns is from an old Winchester reloading book and that is W760 on top of a 180grn SP. I am still going to pull all of the bullets, deprime the cases, do all the case prep, clean the cases, reprise the cases with Federal 210M primers, load each case with 39.0grns of Norma 202 powder and reseat each bullet to an original OAL of 3.025"...

Whats the bullet weight?

Not what's stamped on the box?

They are supposed to be 174grn bullets but, out of the 40 I have pulled and weighed, only one weighed exactly 174grn. Fifteen of them weighed between 174.8 and 175.5. Twenty of them weighed between 173.4 and 172.2. Three weigh 173.9 and one weighs 168.0 exactly. Alot of inconsistencies right there. I reloaded the cases with PPU 174grn FMJBT 's instead...

How consistent was the powder charge weight?  Does look like a ball powder, could be BL-C.

If the ammo has been stored out of the summer heat, it will still be good.  

I am not taking any chance here and will dump all the original powder and primers in exchange for 39.0grns of Norma 202 powder and Federal 210M primers. The other item of contention are the flat-based FMJ's. I have pulled 60 of them so far and only 2 of them weigh 174.0grns. The weight ranges between 168grn to 175.5grns so,, I will not be using those as well.  I will be using PPU 174grn FMJBT projectiles however.  I had every intention to shoot the original bullets but after noticing the extreme differences in weight, I chose the more reliable and consistent weight provided by the PPU projectiles.  Basically,  I paid a ridiculously high price for 81 year old unfired Winchester brass.

NOTICE!! If anyone wants the 80 Flatbased FMJ's to use for plinking or whatnot PM me. No price involved, I am just giving them away...

Ridiculously high-priced Winchester brass indeed. Too bad the bullets were that far apart in weight. They will make good plinking/testing rounds though.

Agree, not really worth the risk of shooting, especially in your “new” Resistance rifle.  But, would be an interesting experiment to see how consistent the muzzle velocities are and what the accuracy is like.  I’d guess hat the bullets are not goin to shoot that well, perhaps 3 to 4 MOA. 

As a reference, my 1943 and 1944 Canadian .303 Mk 7z still shoots 100% reliable and right on spec muzzle velocity.  Accuracy is 2 to 3 MOA.  I also have some 1951 Mk 7z that shoots even better, under 1.5 MOA, and was selected for use in DCRA Matches thru the 1960’s.  

I have one box that will remain sealed so I will never be able to determine consistent velocities or accuracy but, knowing that there is an averaged difference of a 7.4grn spread within each 20 round box, it is suffice to say that accuracy from these rounds would be abysmal. The current reloads have known velocities and accuracy from past experience. 

39.0grns of Norma 202

210M primers 

.311 FMJBT 

OAL 3.025"

Averaged chronographed FPS 8ft from muzzle= 2612

Averaged horizontal and vertical spread of a ten shot group at 100 yards= 1.31"

At that was with a scoped rifle with a used barrel and using a sandbag for support. 

It stands to reason these rounds will be as accurate or better when fired through a rifle with a "new" barrel...

2610 fps, is that a 150 gr. Bullet?

The muzzle velocities are with a 174grn FMJBT 

PM sent on the FMJ's!

Curious if the 2612 fps is a typo, since it’s a 174 gr bullet and 39.0 gr N202? 

My slowest chronographed fps for that load was 2597 and the fastest was 2618 and after a ten shot group, the averaged fps calculated was 2612...

That's "a mighty spicy meatball" from a .303 Lee Enfield!

With 174/180 g\r bullets Norma gives range of 39 Gr of 202 for 2454 FPS ~ 41.0 for 2608 FPS!

Shamu.  I have used 39.0grns of IMR4064 and can only achieve a best possible FPS of 2389 and I have used 39.0grns of IMR3031 and achieved a FPS of 2420. I have been using 42.5grns of VihtaVuori N540 and have averaged a FPS of 2582. It is only with the Norma 202 that I have been getting faster than advertised FPS numbers. Will not matter anyways soon enough. I only have 2lbs of the stuff left and after that I go back to using the IMR4895 first and then the IMR4064 next, and saving the IMR3031 for my last resort...
 

Let me ask you a question. If you were given a Power Glide out of a 1962 Chevy II with the promise that it is all original and has never been touched. Are you going to leave it alone or are you going to rebuild it and add a new filter and fluid to it before you use it?

 Because You do not know the condition internally of 80 year old ammunition and I did not want to take the chance of having something go wrong olskool. And all that work was for something as well. Fresh powder, fresh primers, and match grade bullets that offer excellent accuracy...