Forming 300W / 300BO from .223 / 5.56

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  • Last Post 28 October 2019
Richard Pickering posted this 28 October 2019

For those who have made cases for 300W, do you have a preference in parent cases ?  Do you choose Commercial or Military ? I weighed one SSK casing that was 84gr. Do your cases mirror that weight ? Mine are to be used in a TC Contender 10'' (SSK barrel). Did you anneal ? Did you need to ream necks ? Thanks.

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45 2.1 posted this 28 October 2019

For those who have made cases for 300W, do you have a preference in parent cases ? Yes  Do you choose Commercial or Military ? Military Lake City (LC) from one year production run I weighed one SSK casing that was 84gr. Do your cases mirror that weight ? Don't know Mine are to be used in a TC Contender 10'' (SSK barrel). AR 15 build Did you anneal ? No Did you need to ream necks ? Not necessary for my chamber Thanks.

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Bud Hyett posted this 28 October 2019

For those who have made cases for 300W, do you have a preference in parent cases? - Not really, whatever I have that is one lot number and I know the number of times they have been fired. 

Do you choose Commercial or Military? - Lot numbers, a large enough sample whether commercial or military that I have some extra to use setting up  I prefer commercial, but good military brass is acceptable.. 

I weighed one SSK casing that was 84 gr. Do your cases mirror that weight? - uniformity of weight, say +/- 2 grans, is more important than weight. Some military issue bras will come very close. others will not.

Mine are to be used in a TC Contender 10'' (SSK barrel). - Factory chamber? Setup using the chamber to assure headspace is tight, but the T/C ill close easily.

Did you anneal?  - Always is more than two calibers difference. I once worked .348 Winchester to .50-110 WCF which cured me from buying calibers I cannot make in one pass in the sizing die. 

Did you need to ream necks? - No. The reamer will follow the least resistance in the hole and not even out the neck walls. When needed, I outside neck ream since this removes the high spots. 

Farm boy from Illinois, living in the magical Pacific Northwest

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