Needed: Factory 300 Blackout Case, help with measurments.

[Donald1818]

Hello fellow reloaders.

I am just starting to reload 300bo. and I was wondering if any of you fine fellows wouldn't mind parting with one factory 300BO casing.

I would like to have one as a standard for my trimming.

I am already having some difficulty in determining proper case length.
I have a case gauge, but when i trim my used .556 brass down to 1.368 and insert it into the case gauge , it falls pretty shallow of the tolerance markings on the case gauge.

I can post some pix if needed.

I live in Baltimore if someone wanted to meet up.

 

[rseymorejr]

I can spare one. I'm in Bel Air.

 

[IndispensableDestiny]

I am already having some difficulty in determining proper case length.
I have a case gauge, but when i trim my used .556 brass down to 1.368 and insert it into the case gauge , it falls pretty shallow of the tolerance markings on the case gauge.

Which case gauge do you have? Brand? Are your calipers good?

 

[Donald1818]

After posting this, I went back to the reloading station and took the die apart and reset it.
I must have done something wrong the first time because the reformed brass is now coming out perfectly. the case gauge is telling me the brass is formed correctly.

Thanks.

 

[DocSavage]

Hey there...

An avid reloader of the mystery that is the 300BLK, I have found the below links to be helpful...

http://www.saami.org/pubresources/cc_drawings/Rifle/300%20AAC%20Blackout.pdf

http://www.midwayusa.com/product/251243/little-crow-gunworks-worlds-finest-trimmer-300-aac-blackout

Get GOOD calipers, not Harbor Freight quality - GOOD ONES! Digital are best, dont forget extra batteries. Got mine at the orange store - they've not failed me yet.

Enjoy your time with 300BLK - can be tricky, but it is very rewarding!

Cheers,

Doc

 

[IndispensableDestiny]

After posting this, I went back to the reloading station and took the die apart and reset it.
I must have done something wrong the first time because the reformed brass is now coming out perfectly. the case gauge is telling me the brass is formed correctly.

Are you trimming or cutting to 1.368 before forming the case? If so, give yourself a break and cut longer. Trim after forming. I cut my cases to about 1.390 or 1.400. I trim to 1.365.