303 chamber differences

SuperCub

SuperCub

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I was going through some 303 brass getting ready to load up for a JC I recently bought and noticed a fair bit of difference between the brass I had on hand. The brass is all the same brand, and is all range pick-up stuff, obviously from diff rifles. The three examples shown are about typical to the brass I have on hand.

Is this common to see such a difference in 303 Brit chambers?

303001.jpg


303004.jpg
 
Yes. Because headspace is established on the rim, and the rifles were made over such a long period by so many different manufacturers, you will see a lot of variation in body shape. If you are reloading range pickup .303 brass, inspect it really carefully for incipient separations. There are some really loose ones out there.
 
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I will full length resize and run them through the chamber before loading.

Any time in the past I loaded 303, I just neck sized after firing them once in the chamber.


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But do check them for incipient separations. In brass fired in actual still on issue Gov't. property rifles I have observed up to 20% with incipient separations.
 
SuperCub said:
I was going through some 303 brass getting ready to load up for a JC I recently bought and noticed a fair bit of difference between the brass I had on hand. The brass is all the same brand, and is all range pick-up stuff, obviously from diff rifles. The three examples shown are about typical to the brass I have on hand.

Is this common to see such a difference in 303 Brit chambers?
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SuperCup, and someone may step in and correct me on this, but it looks like the brass on the left may be 303 Epps Improved. Epps used to ream out the chambers to cut out some of the taper and to square off the shoulders. Made for a more efficient design. Either that or it's a grossly oversized chamber. The one in the middle looks about right for most 303's. The one on the right almost looks as if it hadn't been fired at all, or it's been fired from a rifle that has the correct chamber dimentions.
 
An improved chamber would have a straighter body and sharper shoulder. There are all sorts of variations in .303 chambers, some quite distinctive. I have a commercial reamer, and cases from that chamber are different from a SMLE. Ross chambers, both standard and enlarged are different again. If you try chambering assorted unsized fired brass in a rifle, it becomes apparent how different cases can be. If there is no internal groove from excessive stretching, cases can generally be FL sized back to a useful size. I have found that the chamber in my Ross II** target rifle is so small that a case fired in any Lee Enfield will not fit if FL sized. Had to make an additional die to size the case in the area of the expansion ring.
 
At first I thought the one on the left was improved, but there is too much taper which would produce a wider shoulder.


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303 Chambers

I agree that the brass to the far left looks like an Improved chamber. While the 303 Epps is the most frequently encountered, there are several other improved cases with a slightly different shape (the ICBM for example). Epps's are sometimes critized for being too "fat or straight" which leads to reduced magazine capacity or feeding problems, hence the other more tapered improved cartridges. Also, I know from previous experience that 303's fired in a Bren gun will not chamber in a JC. It stands to reason that a Bren would have a larger or sloppier chamber to aid in automatic fire. Full length resizing although hard on brass should solve problems initially. If the brass is to be used in one gun, thereafter, I would suggest neck resizing only, perhaps using the Lee Collet system. I hope this is helpful.
 
hiredgun said:
Full length resizing although hard on brass should solve problems initially. If the brass is to be used in one gun, thereafter, I would suggest neck resizing only.
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I just FLRed all the brass in a Lee die. No problems at all getting into the JC chamber. Neck size only after that.

I'll make sure I have my broken shell extractor with me when I go to the range. :)


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The one on the left looks like an Epps, but it isn't. I don't have any fireformed brass yet from my recently-reamed P-14, but I do have a diagramme:
Epps%20specs.jpg


CH4D (ch4d.com) lists four "303 British" reamers out of the 1420(!) available-

303 British
303 British Improved
303 Epps
303 Indonesian
303 Magnum

:) Stuart
 
tiriaq said:
Yes. Because headspace is established on the rim, and the rifles were made over such a long period by so many different manufacturers, you will see a lot of variation in body shape. If you are reloading range pickup .303 brass, inspect it really carefully for incipient separations. There are some really loose ones out there.
Click to expand...
X2
SuperCub said:
I will full length resize and run them through the chamber before loading.

Any time in the past I loaded 303, I just neck sized after firing them once in the chamber.
Click to expand...
That works well if it's only ever been fired in your chamber. In fact, from what I hear, you'll get better brass life and better accuracy by only neck sizing the stuff from your rifle. You'll need to full length resize anything you find.

Would annealing brass like improved one be a good idea before doing a FLR?
 
The one on the left looks like a normal fired case from a military chamber - the two on the right look either unfired, or from a commercial chamber. (I have a commercial chamber on one of my Lee's - its actually a pain as I have to segregate brass for that particular rifle...)
 
The one on the left is definitely not a 303 Epps. It has far more body taper and a longer neck than the Epps which also moves the shoulder ahead. The Epps case body is almost straight, which is why it is impossible to get more than three of them to feed from the standard LE magazine.

Mine was chambered by Elwood himself, in 1969! Can hardly believe it was that long ago, but that's when he did it. :D

Ted
 
Wally said:
X2

That works well if it's only ever been fired in your chamber. In fact, from what I hear, you'll get better brass life and better accuracy by only neck sizing the stuff from your rifle. You'll need to full length resize anything you find.

Would annealing brass like improved one be a good idea before doing a FLR?
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If the range pick up will chamber before re-sizing, neck sizing is fine for plinking etc.
 
The one on the left is what my casings look like after being fired and i'm relatively sure it's not epps improved. When you figure how many millions of there guns were manufactured, i'm not surprised by chamber differences. It was a military rifle, and as far as i know, the military had no intentions of reloading their brass ;P . The bullet had to come out the end of the gun and the brass had to withstand one firing and consirdering it headspaces off the rim, you could probably chamber it with a drill bit, lol.
 
The chambers even on well made 303s are much improved. I have 1917 P-14 Winchester and my buddy had a genuine #5.Both rifles are in excellent shape. Both chambers left the cases much improved and very very similar in the improvement,too.I couldn't tell the difference with a caliber.
 
The brass that comes out of my No.4mk1/2 looks exactly like the piece one on the left. So does the brass that comes out of my No.5mk1.

Actually it's amazing how much extra case capacity you get by using once fired brass instead of full length sizing.
 
Tudenom: that is an interesting point..have you ever measured the diffence?

I have read that to measure capacity use water (and weigh the contents) Has anybody here ever done that and how did you do it?
 
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