Chamber shoulder and case shoulder gauge for .303?

[Parashooter]

Seems to me there's no significant difference in the shoulder location of unfired .303 cases or loaded ammo in my little stash - regardless of national origin



Anyway, it hardly makes much difference since the chambers are designed with plenty of clearance at the shoulder, and the intent is for the cartridge to stop on the rim long before the shoulder touches (mud, not reloading, being the original plan).

Near as I can figure, the purpose of the shoulder in the Wilson gauge is to alert the user when the head-shoulder dimension is too long - which would leave the cartridge base protruding above the back end of the gauge. That could be a useful bit of information to help reject cases that need some F.L. sizing to fit in a (mythical?) "standard" chamber.

Mr. Horton is confused about my case stretching tests. The one I reloaded "19 times without any case stretching." didn't involve any spacers (neoprene, nylon, or otherwise). It was an R-P commercial case from which I removed the rim to demonstrate that the skinny .303 shoulder was entirely adequate for rimless-style headspace control in a neck-size-only operation. As can be seen in the image below, there ain't no place to put a spacer on this one!



I suspect Ed was the unlucky purchaser of a bad batch of Winchester cases - which may have been "outsourced" (Can you say "S&B"?) instead of made in USA - and he's made some questionable generalizations about American brass quality on the basis of this experience. As long as some of us keep reminding the audience that "it ain't necessarily so", there's plenty of room for lively discussion. (Sometimes he's even been known to admit someone else might be right.)

[Edward Horton]

In this case Mr. Parashooter I’m NOT willing to admit you are right.

I have NOT made some questionable generalizations about American brass.

IF the American ammunition companies are in fact downloading .303 ammo to pressures lower than 43,000 CUP it would explain why the .303 cases do not hold up.

I also do not want YOU taking the liberty of making assumptions on the cases I buy or the tests I conduct on them, your comments here are uncalled for and insulting.

They are especially insulting because you think you are the only one capable of reaching the correct conclusion in these forums or anywhere else, in essence you are saying Parashooter is never wrong in your typical patronizing manor.

ireload2 has the exact same problem you do, he oils all of his cases before he shoots them and ignores the word “bolt thrust”.

Have a nice day

[Edward Horton]

The shoulders on my Remington and Winchester cases are not assumptions on my part Mr. Parashooter especially when the cases have five different lot numbers and are newer than your cases.

I truly wish you would think the next time before YOU make assumptions.

[Patrick Chadwick]

I am not arguing with Parashooter or Edward, but I feel that something is confused.

I do not fire gauges, I fire real-world cartriges. And the examples I have from PMC and S & B look EXACTLY like the pics provided by Edward - a good 1/16" stretch after firing. Why?

The 303 is a rimmed cartridge. Which means is it supposed to be held by the rim. The clearance (I am trying to avoid the word headspace) between the rim and the bolt face when the cartridge is pushed forwards by the strike is the amount by which the case can stretch. IF and ONLY if the case shoulder perfectly matches the chamber before firing. Otherwise the shoulder will also move forwards. Which it does. As is inevitable in chambers cut to cope with dirty/max tolerance cartridges that were NOT intended to be reloaded.

The PMCs in my collection have a rim thickness of 0.056-0.057", the S&Bs about 0.058-0.059". I do not know what the maximum bolt face to chamber spacing may be in practice, but it is probably more like 0.070" for real-world Enfields.

Whatever the value, this clearance of 10 to 15 thou is MUCH less than the stretch observed by Edward, myself, and my friends who shoot Enfields. We should think of the case being pushed forward rather than the base being pushed back.

The root of this trouble is that (surprise, surprise) the British were so bloody-minded that they did not make rifles to SAAMI specifications. How could they have been so short-sighted as not to realize around 1900 that the Americans would set up an organization in 1926 that would define tighter measurements? All those Tommies in the trenches should have been saying "Sorry sarge, I can't use this rifle, I can chamber any old cartridge, so the chamber is obviously too generous" - or not?

Seriously, the answer it to adjust the cartridge cases to fit the rifle, not the rifle to fit gauges that were defined decades after the rifle was built. That means, as for so many milsurps, fire-forming and neck-sizing, dumping cartridges that show too much stress before they separate. In effect, this means treating all cartridges as if they headspaced on the shoulder, and thus only re-using the cases in the rifle in which they were first fired.

Patrick

[Amatikulu]

I visit many gun related forums due to my interest in shooting and collecting and am fully aware of the altercations and personality clashes that occur.

This Lee Enfield Forum has been largely free of such unpleasantness.

We the moderators intend to keep this and all other forums on this site a place where we encourage the open exchange of information amongst the general military surplus collector community, thereby helping all of our members to better enjoy their chosen hobby.

I don't feel that anyone on this thread has "stepped over the line" but am very aware of the possibilities for this to spiral downwards. Hence my appeal to all the contributors to avoid any personal jibes or attacks - discuss your theories and present your information - I for one am interested in the content of this thread and would like to see it continue. Remember at the end of the day it's OK that not everyone agrees with you

Amatikulu

[jmoore]

I reckon for military purposes the only real critical controlling dimension is the rim thickness of the case. Commercial ammo makers also don't worry about reloading, they just want you to buy more ammo. If case life stinks all the better.

Something I've noticed is that No 1's and No 4's chambers are cut differently. If sorted and neck sized only cases fired in a particular "model" will fit quite a few rifles w/ no further attention as to EXACTLY which weapon in which they were fired. Works espcially well with the "T's"!!! Oh, No 3's don't fit well in the others, but there's only one that I've shot extensively.

[Edward Horton]

Amatikulu

The problem Amatikulu is oil and grease in the chamber and increased bolt thrust is NOT a theory nor is the damage it does a theory, they are facts.

The problem is people are unwilling to admit lubing cases to fire form them can cause damage and the books say to remove all oil and grease from the chamber.

The problem Amatikulu is this post WAS reopened to start an argument.

The problem Amatikulu is people would rather argue than admit they are wrong.

The following are not theories they are printed warnings, one was written in 1946 specifically on the Enfield Rifle and the other is from a current reloading manual.

[Parashooter]

. . . We should think of the case being pushed forward rather than the base being pushed back.

I have seen this idea with fair frequency and eventually decided to test it -



I believe that when a rimmed cartridge is fired with generous shoulder clearance the case expands outward to fill the chamber and there is little or no elongation (stretch) due to brass being "pushed forward". I'd be delighted to hear details of any tests that either confirm or refute what I've concluded from my little experiment.

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Ed, I apologize for the offense. It was not my intent. I have great confidence in your measurements and observations about the .303 cases you've examined and shown us. That they differ from what I've experienced tells me there has been some significant variation in production - enough that I question the value of any generalization based on what either of us have observed in a variety of specimens.

To be specific, I question assertions that -

• US makers are routinely loading .303's to reduced pressure.
• Shoulder clearance is a defect in (new) rimmed cases.
• There is a qualitative difference in the metal US makers employ for .303 cases.

All of these may be valid points. I'm just saying that I haven't yet seen any conclusive evidence to support them and my experience differs. Please don't stay angry.

[Patrick Chadwick]

Practical news as a change from hotly argued theory!

I have just done a quick check according to the Parashooter method, using a 9 para case fresh out of a long-barrelled Artillery Luger (not mine, alas!)

PMC shoulder before firing 2.596"
PMC shoulder after firing 2.630"

PMC cartridge length before firing 2.212"
PMC cartridge length before firing 2.231"

Increase in case length 0.019"
Shoulder movement 0.034"

That 0.034" shift of the shoulder is a lot more than any bolt face - cartridge base clearance. That clearance could be zero, and the stretch caused by the shoulder movement would still be alarming.

Chuck away those gauges and fireform some cartridge cases to fit the real rifles!

Patrick

[Patrick Chadwick]

Parashooter, your latest posting appeared when I had already posted measurement. That was a very neat idea with the scribed lines. Have you got any explanation as to why the first scribed line (at 1.570") actually moved back towards the base? It is surprising that the spacing of the three lines has remained the same. although the shoulder has moved from between the first and second lines to between the second and third lines.

If the shoulder is just rolling forwards, without any stretching, surely one would expect the gap to expand between the first and second lines, and to contract between the second and third lines?

Patrick