Rolling Shoulders

[robpiat]

I generally dry tumble brass before seating. I even find that letting it sit for awhile after tumbling makes it inconsistent. I think it has to do with a variety of variables but a fresh removal of the oxidation and a little dust makes it feel more consistent. I think if your neck tension is ok this is related to galling or stickiness for lack of a better description.

 

[Cliffhunter]

Wow, obviously the rim of the neck didn't go into the chamber. How did you force the bolt shut on that?Or did you do that seating the bullet.

 

[Roughrice]

I'm with Oregonian and others.
I've seen this happen with my buddy's PRC seating long bullets.
He had to back die out and reset.

 

[esorensen]

It looks like either the die is catching the case mouth, or there is too much neck tension. With the mechanical advantage of the press, something has to give and the shoulder collapses. Maybe you can try a sacrificial piece of brass and trim it much shorter and see if that is the issue, or use a larger mandrel to see if that is the issue. You said it did 212's fine, so my guess its a neck tension thing.

 

[MASH]

Always run your new brass through the sizing die, it will clean up any small Deformities. I use ADG in my rum also never had this issue, but have never used those bullets.

 

[Shane Lindsey]

Don't trim. ADG is usually pretty short.

I think neck tension is your issue.

 

[Roughrice]

Always run your new brass through the sizing die, it will clean up any small Deformities. I use ADG in my rum also never had this issue, but have never used those bullets.

This to clean up neck tension or the die setting in press

 

[Chas1]

I squashed a 38 spec case cause I had the crimp to low and seating stem to high. Check your die setup.

 

[Tumbleweed]

Sounds like you have a die adjustment ruled out. I'd say you have a LOT of neck tension or seating resistance causing this. For whatever reason, I've found that HBN coated bullets seat harder. I know it doesn't seem to make sense. I do size my 30 cal necks with a .307 or .3075" mandrel to get my seating "resistance" where I want it. I've been spraying my bullets with Hornady One Shot case lube and it does WONDERS for seating. Bullets seat like butter with very consistent seating pressure

 

[Chas1]

Is the brass long?

I always full length size new brass.

Absolutely without a doubt I always FL all new/used brass that hasn't been fired in my gun.

 

[Mike Matteson]

Recheck your die setting. Raise your body of the die up some.

 

[shphtr]

Agree with too much neck tension - had exactly same problem which resolved with dry lib even tho Hbn coated. I always VLD champ her case mouth for 20 degrees. Good Luck

 

[Mad Minion]

Check this bushing on your sie and make sure it moves freely. The seating stem should pass through it without a round in it. Same issue I had and that bushing was sticking to the wall of the die. Cleaned it and put gun lube on it everytime I use it

 

[DaleJ]

Alco bullets are rebated boat tail design. Seen this happen when "donuts" are involved, Necks need to be sized to remove irregularities inside neck. Use a 22 degree chamfer tool. Also check bullet seater plug, make sure tips are not bottoming out, easily fixed, drill it a bit deeper.