.30-06 "RA 28" vs "Peters 27"

I just shoveled snow for like…the whole day and my mind is gone. Please, remind me why “RA 28” has a deep groove around the primer. But “Peters 27” does not. Peters is on the right for comparison.


RA 28 has a heavily ring-crimped primer for use in machine guns, where a backed-up or blown primer might stop the show while the Peters 27 round does not because it’s not intended for full-auto fire. I think. Other Remington .30-06 WW II dates have the same heavy crimp.

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The Deep groove was introduced in 1917-18 for Aircraft MG ammo
(MARLIN M1918 improvement of the Colt M1895).
It was to prevent Primer blowout with subsequent gun jamming in aerial combat.
It was maintained in all .30 cal M1906 And early M2 for aircraft use into the 1940s, when .30 cal aircraft guns were replacedby .50 cals.
RAF 1940s orders from Remington
(".300z") were also this “aircraft standard”

The Italians introduced the groove to solve both a hardness problem in the head, and also to prevent primer blowout in Rifles ( in mid 1890s); France adopted it in 8mm Lebel for proper alignment of pointed Balle D in Lebel Tube mags, and also for Aircraft use:
CSRG 1913, and Hotchkiss Portative in Aircraft.
The French continued with this ring in the M24/29 7.5 Cartridge.
And their later M1949 7.62
( cal.30).

Doc AV

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The deep annular crimp on the RA cartridges was a practice of that firm, not a contract requirement. The fact the Peters round lacks the crimp does not indicate it was intended for use only in manually operated arms. Jack

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I thought the English / British contract WW II DocAV mentions called for the ring crimp. And I believe the 1928 date is / was an educational contact from the US government.
It also exists dated 27.
None of the Remington WW I era [ RA 17, 18, H17 & H18 ] I have, have this ring crimp, not that I have everything

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One of the RAF M2 contract rounds.


The WWI rounds with deep ring were USCCo, both normal draw, and impact extrusion “Hooker” Patent. ( they were still stab-crimped as well, 3 and 4 stabs).

Doc AV