Schrodinger's headspace - a problem that isn't?

[psteinmayer]

This talk of problems with .303 case failures makes me a little nervous. I just loaded 100 new Winchester cases (Hornady 150 gr SST, 36.0 grains H4895, CCI-200) for my new Lithgow. Should I be concerned???

[butlersrangers]

Paul - Shoot some rounds and observe your brass.

FWIW - My WW-2 Lithgow S.M.L.E. doesn't appear to show problems.

[FredC]

I can not see a problem with 308 bullets and Krag pressures in the solid not springy Krag. You all did it with no problems during the great ammo shortage. I ordered 25.06 Remington cases during that time and could not get any. Finally got Lapua match .222 cases as Remington was also unavailable. Stupid hoarders.

[butlersrangers]

Fred - Psteinmayer is concerned about his re-loads (in .303 British) for an Australian made Short- Magazine Lee-Enfield Mk-III, (manufactured at the Lithgow arsenal).

He is worried he could have an experience, like I did, with my BSA rifle.

[Parashooter]

This talk of problems with .303 case failures makes me a little nervous. I just loaded 100 new Winchester cases (Hornady 150 gr SST, 36.0 grains H4895, CCI-200) for my new Lithgow. Should I be concerned???

No. That's about a 25000 psi (piezo) load per QuickLOAD. You'll be lucky not to get sooty cases!

See https://www.milsurps.com/content.php?r=296-Headspace-101-for-.303-s for more info.

[butlersrangers]

'Parashooter' - Thanks for your excellent work on explaining head-space and forces acting on a rimmed 'bottle-neck' cartridge.

[FredC]

Fred - Psteinmayer is concerned about his re-loads (in .303 British) for an Australian made Short- Magazine Lee-Enfield Mk-III, (manufactured at the Lithgow arsenal).

He is worried he could have an experience, like I did, with my BSA rifle.

WHOOPS! I was remembering all the members using 303 cases during the shortage. Sounds like you got an outlier on your remanufactured model. No use even speculating why it had all the separations with reloads since you do not have it anymore.

[butlersrangers]

Its hard for me when discussing Krag (.30-40) head-space, which is relatively trouble free, to avoid looking at a similar cartridge (.303 British) with a "reputation", and a particular 'like new' Lee-Enfield rifle that was problematic.

'Comparing Apples and Pears' 'after The horse has left the barn', maybe ... but, I found it educational to ponder & discuss.

The thread allowed some improvement in understanding 'head-space' and offered some practical solutions, in the end.

Hey, Schrodinger! Why is that box of your's making cat sounds?

[psteinmayer]

No. That's about a 25000 psi (piezo) load per QuickLOAD. You'll be lucky not to get sooty cases!

See https://www.milsurps.com/content.php?r=296-Headspace-101-for-.303-s for more info.

That's good to know... although sooty cases doesn't thrill me either, LOL.

I consulted several load manuals and data before settling on that load. I wanted to keep it light starting out since I've never dealt with an SMLE before (and I'm a heck of a lot more cautious these days). Perhaps after firing these first hundred, I'll bump the charge up a little.

[Parashooter]

... although sooty cases doesn't thrill me either, LOL.

I consulted several load manuals and data before settling on that load. I wanted to keep it light starting out since I've never dealt with an SMLE before (and I'm a heck of a lot more cautious these days). Perhaps after firing these first hundred, I'll bump the charge up a little.

I suspect you'll want to increase the charge significantly just to fully fireform your cases. Here's a QL table predicting results with H4895 -

[tt]Cartridge : .303 British (SAAMI)
Bullet : .312, 150, Hornady SP 3120
Cartridge O.A.L. L6: 3.075 inch or 78.11 mm
Barrel Length : 24.0 inch or 609.6 mm
Powder : Hodgdon H4895

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.163% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-11.6 82 38.00 2312 1781 28477 6126 92.3 1.465
-10.5 83 38.50 2341 1825 29413 6221 92.8 1.444
-09.3 84 39.00 2369 1869 30379 6315 93.4 1.423
-08.1 85 39.50 2397 1914 31377 6407 93.9 1.404
-07.0 86 40.00 2426 1960 32408 6497 94.4 1.385
-05.8 87 40.50 2454 2005 33471 6585 94.9 1.366
-04.7 89 41.00 2482 2052 34570 6671 95.4 1.347
-03.5 90 41.50 2510 2099 35706 6755 95.8 1.328
-02.3 91 42.00 2538 2146 36877 6837 96.3 1.310
-01.2 92 42.50 2566 2194 38088 6916 96.7 1.291
+00.0 93 43.00 2594 2242 39340 6993 97.0 1.272
+01.2 94 43.50 2622 2291 40632 7068 97.4 1.254
+02.3 95 44.00 2650 2340 41970 7140 97.7 1.235 ! Near Maximum !
+03.5 96 44.50 2678 2389 43351 7209 98.1 1.218 ! Near Maximum !
+04.7 97 45.00 2706 2439 44780 7275 98.3 1.200 ! Near Maximum !
+05.8 98 45.50 2734 2489 46256 7339 98.6 1.183 ! Near Maximum ![/tt]