New purchased brass - .303 for Enfield MK1 #4


March 17, 2008, 08:53 PM
I just bought some brand new never fired .303 brass. I bought it so i could basically not full length resize and only neck size to try and not end up with case separation. I posted my problem about 3 weeks ago and most said only to resize for my Enfield Mk1 #4. Sooo - my question is since I have this brand new never fired brass can i just neck size and i am good. I did load a few of the new brass just to see if it chambers ok and not tight and it seemed ok. I will trim to the proper lenght also and than neck size. Any pros or cons to this. Just trying to get some life out of my .303 cartridges plus it looks bad when you pull the bolt back and the rear of the case is loose in the chamber and the rest of the cartridge is still in the chamber. Yikes.


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March 17, 2008, 08:57 PM
I don't know, but I'm also interested in the results

Dumpster Baby
March 18, 2008, 12:19 AM
Your new cases are essentially the correct length now, and would only need a neck resizing to maybe true up the necks. Sometimes new brass is slightly out of round from handling.

Trimming shouldn't matter too much in such loose chambers unless you are crimping in bullets with a cannelure. If no cannelure, the cases can gradually stretch quite a bit before you would need to trim them again.

Do some research on the subject of annealing your cases, too.

My .303 dilemma is having both a #4 and a #5. Which one to neck size for?


March 23, 2008, 12:36 PM
if you dislike case head separations, expand the neck of new brass to 8mm or .35 cal, then adjust your .303 sizing die until the case just chambers, headspacing on the shoulder instead of relying on the rim. enfields are notorious for having generous chambers because the military doesn't care about brass longevity...we do.

if you have more than one .303 brit, coding the brass to the firearm would be necessary.


Jeff F
March 23, 2008, 01:18 PM
I've got three No 4's that I shoot regularly. In two of them the chambers are so close, neck sizing and my reloads are interchangeable between 1 and 2 and will chamber fine and fire with good accuracy in 3. 3 has a rather large chamber and if I neck size only, those cartridges will not chamber in 1 or 2. At the range I take two big marked zip lock freezer bags and brass from 1 and 2 go into one and brass from 3 goes into the other. With new brass, just load it up and shoot it. I don't have to trim until at least three or four loadings and with light loads I can go even more. Best way I have found to annealing your cases is to melt a few pounds of lead and dip your unprimed case necks into the molten lead for a second or two then give it a couple of light taps on the top of the melting pot to make sure theres no lead left in the neck, ware a welders glove.

March 24, 2008, 06:51 AM
If I wanted to make 303 Brit brass last a really long time,

I would de cap the fired brass to get the old primer out.

I would remove the decapping stem with expander ball.

I would consider paying $10 to Forster to hone out one of their sizer die necks to .003" smaller than my loaded ammo neck size.

I would partial full length resize to get most of the neck sized.

I would shoot wimpy loads with slow powder.

I would anneal the necks when the first one splits.

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