.308 (7.62 NATO) SB/FL Sizer Die Test

[40calfunk]

After rereading Zediker's article on reloading for the match M14, I wanted to perform my own test to quantify what happens to brass during the resizing process.

I have two attachments depicting those actions; one for Small Base and the other for Full Length sizing dies (RCBS)...pretty interesting findings.

308 FL Test.pdf
308 SB Test.pdf

Basically, I had some old SBS once-fired brass (unknown how/what fired from) and am getting back into reloading after quite the hiatus. My goal is to get consistency in my reload operations and what better way to learn/adapt/apply, than to quantify it!

Things that are left up in the air still:
-Concentricity of the fired brass is unknown (many Mil-spec chambers are ovaled, thus producing fireformed "oval" brass". I suspect many of these cases are/were ovaled. Looking to get a TIR/concentricity gauge setup soon.
-Neck thickness unknown...special micrometer is on the way (which may get me into neck turning for my thicker, "military" brass if an inconsistency is present.

Just wanted to share my work with anyone that may be interested in this sort of thing. Before you ol' timeys go off the rail, I have OCD when it comes to this hobby and actually enjoy doing all the "extra work"! It's how I learn stuff.

[kcstott]

After rereading Zediker's article on reloading for the match M14, I wanted to perform my own test to quantify what happens to brass during the resizing process.

I have two attachments depicting those actions; one for Small Base and the other for Full Length sizing dies (RCBS)...pretty interesting findings.

[ATTACH]1115025[/ATTACH]
[ATTACH]1115026[/ATTACH]

Basically, I had some old SBS once-fired brass (unknown how/what fired from) and am getting back into reloading after quite the hiatus. My goal is to get consistency in my reload operations and what better way to learn/adapt/apply, than to quantify it!

Things that are left up in the air still:
-Concentricity of the fired brass is unknown (many Mil-spec chambers are ovaled, thus producing fireformed "oval" brass". I suspect many of these cases are/were ovaled. Looking to get a TIR/concentricity gauge setup soon.
-Neck thickness unknown...special micrometer is on the way (which may get me into neck turning for my thicker, "military" brass if an inconsistency is present.

Just wanted to share my work with anyone that may be interested in this sort of thing. Before you ol' timeys go off the rail, I have OCD when it comes to this hobby and actually enjoy doing all the "extra work"! It's how I learn stuff.

don't waste your money on a concentricity gauge. I know of more than a few national level shooters that pay zero attention to bullet run out. a bullet could be .010" run out and still produce single hole group at 100 yards.

Out of round chambers is a different problem and can be checked with a chamber cast and calipers.