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IMI "commercial" .308 brass capacity?

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29 December 2018, 04:51
Samuel_Hoggson
IMI "commercial" .308 brass capacity?
Speer #15 shows most .308 Win data using "IMI commercial" brass. Note is made of their using "IMI military" (pg 407) brass. Well, there aren't any loads listed using "military" brass. So....

Am wondering if there is a difference between the two or, better, can give some indication of case capacity of IMI commercial? Ie., how much to back off starting loads. Trying to save myself powder and time. Thanks!
29 December 2018, 21:43
Ratwhiskers
To my limited knowledge IMI made commercial "Match" brass and their "New Mil'Surp" stuff. The Match had a capacity closer to other common types of brass 1/1.5grn internal capacity, while l do know the Mil'Surp needed needed backing off two grns from my Lapua brass loads.
29 December 2018, 21:58
Samuel_Hoggson
Thank you!

My LC and RP loads end up giving same chrono results w/same charge. This, despite the LC brass weighing avg 10 grains more.

Just did an internal capacity check of Winchester, RP, and LC'14. All FL sized in same die, primed, same trim lengths.

The Win took 57.2 gr 748, flush filled to top of neck. The RP and LC both took 54.2 gr.

Anyway, sounds like I should back off when using their "IMI commercial" data.
30 December 2018, 22:54
Ratwhiskers
Samuel, you're very welcome Sir.
lt's always prudent to back off a bit and work back up with a batch of untried new brass, just to be on the safe side.