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Discussion Starter · #1 · (Edited)
Ever wonder why your .303 cases don’t last long when you reload and the importance of fire forming your new brass before loading to a higher pressure.

Below is a sectioned Winchester case from a commercial box of preloaded factory ammunition, the case has stretched .010 (ten thousandths) in the web area on firing, the first or second time this case is reloaded the case will separate if not inspected carefully.

Our American made .303 cases have thin rims and are skinny at the base at the web area and do not like being shot in military Enfield’s, the case below was fired in a 1943 Maltby with the headspace set at just under .067 and the rim thickness is .058.

This equates to a .009 thousandths head gap clearance or the air gap between the bolt face and the rear of the case, plus the distance the base of the case stretched outward to meet the chamber walls.

Our problem is our American made cases were not designed to fire in a military .303 Enfield BUT I checked 500 Greek HXP once fired cases on the same gauge below and NONE of these cases had any thinning in the web area and they were fired from *machine guns and several different Enfield’s.
(*The head space in these would have been greater than in my Enfield)

Welcome to the world of company bean counters and the bottom line of making high company profits.

In the photo below the case is moved approximately 1/16th of an inch into the “valley” in the case caused by stretching and thinning with .010 loss in case thickness.
 

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Good info ed, this is exactly what i as a newish reloader for enfields like to read, as well as idiot proof terms that i can get my head around. keep it coming....
 

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Discussion Starter · #4 · (Edited)
would "the load" 13 gr red dot be a good load to fire form the cases? dave
No the pressure would be too low and the case would head space on the primer.
(The base of the case would not touch the bolt face)

The cases on the left has head spaced on the primer from a low pressure load such as your 13 grains of Red Dot, the case on the left has head spaced on the base of the case from a higher pressure mid range load from a reloading manual.




Another method would be to use rubber o-rings at the base of the case when fire forming to “push” the case against the bolt face and lighter loads could be used to fire form the cases.






If you can the best method is to decrease head space and get rid of as much head gap clearance or the air gap between the bolt face and the rear of the case and reduce the stretching area to as small as possible.




Red and yellow colored areas on the web area of the case below are areas of high stress and stretching, reducing head space reduces stretching and stress on the case.





Please see Parashooter's excellent detailed “Head space 101” on the 303 it is a very good read below.

http://parallaxscurioandrelicfirearmsforums.yuku.com/topic/3361
 

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Please see Parashooter's excellent detailed “Head space 101” on the 303 it is a very good read below.

http://parallaxscurioandrelicfirearmsforums.yuku.com/topic/3361
I read the lesson at the link above a week or so ago. It goes further and is put together better than any other explanation I have seen. All in terms that the layman can understand, and will probably add something to most experienced people's understanding as it did for me.

I raise a glass to you, Parashooter. You've done us a great service!
 

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Very interesting. I had wondered about using new brass and handloads, but wondered how to prevent the "original sin". Now, I know.

Thanks.
 
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