Forming 300 blackout shoulder problem

[bangbangping]

Comparing yours to cdl’s, it looks like the Hornady die just really does not do a very good job of forming a shoulder.

What dellet said. For reference, RCBS on the left and Redding on the right. Redding creates a softer shoulder, too, although better than the Hornady.


If it were me, and not having tools to check everything, I'd screw the die OUT in 1/8 turn increments until a piece of brass won't chamber easily by hand. Then turn it in just a bit at a time and try until it will. Lock the die there, form a few, and see how they shoot.

Or maybe buy an RCBS FL die.

[760405reloader]

It was just a spare shellholder i grinded for testing. I think the hornady dies do not do a great job of making a shoulder and are just meant for grabbing an already formed shoulder. How do i safely fire form it after bumping the shoulders back?

[760405reloader]

Which rcbs die is that? Looks like make cases shoulders right out of the chamber

[760405reloader]

My*

[bangbangping]

Which rcbs die is that? Looks like make cases shoulders right out of the chamber

It's the standard RCBS FL sizing die. https://www.amazon.com/RCBS-Full-length ... B00B4S9WHE

[760405reloader]

Awesome thank you. Thatll be cheaper than buying the redding form die plus extended shellholder

[FatAlbert]

760405reloader: I have one question for you "have you fired any of your formed cases in you gun". They should fill out on the first firing.

[plant.one]

760405reloader: I have one question for you "have you fired any of your formed cases in you gun". They should fill out on the first firing.

wanting to make the best brass you can at forming has nothing to do with what you just said. and i find it completely unfair to critizie someone for wanting to get it right the first time.

yes of course they'll fire form - or at least MOST of them should - but a nice quality sharp shoulder helps set headspace and case volume as close to "normal" right off the bat.


a big part of what makes this caliber so desirable to convert is that you dont *NEED* to fire form for it. get the right equipment (good die) and get it damn near 100% the first time around. no need to waste bullets and powder - and barrel life - just to make brass.

my $0,02 usd