,303 british factory load primer backed out & holed


December 30, 2011, 12:15 AM
I remounted my scope and took a box of remington factory loads down to where I have a target set up in my back padock to sight it in 4 shots in a 2" group with the fifth a flier nearly 10" higher I looked a the case and noticed the primer had backed out a bit and was holed where the fireing pin struck .IS this fairly common with remmington facory loads or have I just got an odd one



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December 30, 2011, 03:05 AM
Better check the head-space on your chamber.
The SMLE's have numbered bolt heads that can be replaced to compensate for lengthened headspace for which the rifles are prone to develope.

That particular round was shoved further into the chamber than the others, and upon firing was shoved further by the firing pin. The primer backed out upon firing and also caused the piercing of the primer cup. This is also common in many .30/30win chambers/rifles.

The ammo is nominal for factory .303Brit, which is loaded a tad light by Remington, for just the reason you are holding in your hand.....

Reloaded ammo can avoid this by not setting the shoulder back when resizing the brass and using a stouter primer. Speer makes a primer with a thicker cup called the CCI#34.

But before proceeding, I'd have the headspaced checked and/or corrected.

Joshua M. Smith
December 30, 2011, 04:12 AM
Ditto on the headspacing.

I had a Lee-Enfield musket that was popping primers and backing them out with .410 shells. The gun went away, but then again that one wasn't worth it to fix.



December 30, 2011, 06:48 AM
.303 British rifles headspace on the rim. Military tolerances set the rim recess at around .074". Remington .303 cases often have rims around .055" instead of the correct .063". The original makers of the Lee Enfield were not concerned about case life for reloaders but reliability in the field with ammo from many sources. If that only happens once and a while, don't worry about it. Lee Enfields vent escaping gas very safely. If you reload, fireform your new brass to headspace on the shoulder then neck size and keep that brass dedicated to that rifle and all will be well. You might also check on your fireing pin protrusion, it might be set a bit long.

December 30, 2011, 09:20 AM
Thanks for the responses I've put a couple of hundred rounds throgh the rifle this is the first time I've had this happen .

I normally use Remington Brass & primers when I reload when I saw factory loads on special for not much more than the price of new brass I grabbed a few boxes .

One of my concerns is that the flier was 10" high @100yards which leads to the possibility of wounding a animal rather than takeing it cleanly I expected to get factory ammo at least on the target sheet.I can normaly do that with my reloads without useing sandbags.

I'll get a vernier & check the rim thickness on some of the factory rounds and on some the have been reloaded a few times and see if there is any diference.

December 30, 2011, 09:54 AM
Prvi Partizan 303 ammo from what I've read has rim thickness that is much closer to the origin British 303 cartridge. A good article I came across on reloading 303 a while back,I plan to use the O ring technique when I start loading for my CAN. LB.


December 30, 2011, 11:23 AM
No conclusion can be drawn based on the information provided, the protruding primer indicates the case locked onto the chamber but did not stretch the case between the case body and case head, meaning it would appear that case had a reduced load, or the barrel is worn out, a worn out barrel will allow the bullet to run down the barrel without forcing a build up of pressure, or, the bullet diameter was too small.

The hole in the primer is about the .7854 thing, the pressure inside the primer was greater than the firing pin spring could/can hold, meaning the pressure inside the primer/case forced the firing pin back when the dent in the primer was removed or by design, the pressure inside the primer cause the primer to conform to the nose of the firing pin.

The fact the primer backed out indicates the rifle has excessive head space, the amount of head space can not be determined by protrusion on a fired case because there is a lot of movement between the case and primer, I am guessing, you had cases that were ejected without protruding primers? On those cases and assuming the case locked onto the chamber, the cases without protruding primers stretched between the case head and case body, I do not shoot 303 British rear locking rifles, I do not shoot Krag 30/40 rifles, again, I check head space first, the effort is not worth the failure built into the design, have a 1905 Ross and P14s that have or soon to have Wildcat type chambers.

F. Guffey

December 31, 2011, 09:26 AM
I measured the rim thickness on the remington & winchester cases I have .055" - .056"
since I have several boxes of reminton factory loads left what sized O-rings should I use.

December 31, 2011, 12:17 PM
I've seen the primers backed out slightly on Rem brass from my g/f's SMLE (no pierced primers though). Headspace has been checked good by the gunsmith. The primers don't move on S&B or PPU factory loads, only Remington. Figure it's either Rem has the primer pocket a bit on the loose side or the rim thickness issue mentioned above. Definitely get your headspace checked though.

PPU online costs half what Rem does locally, so we only have those 20 Rem cases and don't intend to get any more, will have to see how they perform as reloads.

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