Reloading without resizing?

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Nathan

New member
I shot BR and I've yet to see chamber reamer that will resize a 6ppc case. A chamber reamer make good seating die and make good neck die.
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I agree, but it was popular at one time...they made bump dies with neck bushings that were cut with the chamber reamer.....why? Because the neck angle would be perfect and the walls could be held to chamber shape while sizing the neck and giving a small bump to the shoulder...remember, these guys are looking to bump 0.0005-0.001”, not the 0.002” most fl users are bumping.

Then there were/are the fl die folks that are sizing the whole case, but those dies are set up for sizing the case minimally in the diameter....probably 0.0003” and about 0.001” bump, and usually a neck bushing set to 0.0005” under bullet diameter...these number are approximate.

Finally, there was a group that bought Lapua brass and ran it without any sizing or brass prep....these guns were mostly chambered for 6mm PPC (Lapua) which meant the neck area was sized for the case to safely expand, then “spring back” to the diameter before firing. A really cool idea, if you ask me!


Remember none of this can be duplicated in standard commercial actions and barrels as they are setup to balance weight and strength....this means they flex in the bolt and chamber slightly, creating brass which needs more sizing. Big actions, large shank barrels, etc
 
U

Unclenick

Staff
Yep, bump dies. There are commercial dies that Forster calls bump dies, but if you don't have an exact match to the chamber around the perimeter, I don't see how you can make them that don't also size the case diameters a little. If the die were allowed to be wider than anybody's chamber, trying to extrude the shoulder down closer to the head would fatten the case and keep it from going back into that chamber. So they have to err narrow.
 
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edward hogan

New member
re: using a reamer to make a tight-chamber sizing die...

Custom finishing reamer to cut the rifle chamber. These are pretty spendy. Use a standard finish reamer that has been honed a couple thousandths, or 15 ten-thousandths to match the chamber for minimum effective sizing and you are in business. Most of the reamer makers offer sharpening services; maybe they also can do a honing job to given specs?

I have long wondered why sizing dies are made of such greatly hardened steel. Carbide is pretty explanatory, for no lube sizing; but can sizing brass cases actually wear stainless or other non-leaded steel alloys to any significant degree over even 50,000 sized cases? Cases are lubed to begin with...

I modified a Redding S .243aI sizer to work for a .308ai barrel I reamed. Taking the heat treat out turned the die a royal blue. Had to open the neck, but there were no other options for a .308AI bushing die. Worked great!

I am a Big Believer in short oal chambers for accuracy and to eliminate most case stretch. Have never done a minimum OD chamber though. Would seem to be the ticket for harnessing all the pressure your powder charge generates and way reduce brass being 'worked'.
 
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