Rolling Shoulders
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Without being there and inspecting it, it's hard to diagnose.
But...If seating die setting is adjusted correctly, and you are still crushing necks then there is either a problem with internals of the seating die dimensions or...something bad wrong with neck sizing (or FL sizing) setting... wether it be brass thickness or bushing (or non-bushing) sizing, mandrel sizing or inside and outside chamfering... you have a problem that only precise measuring of equipment will figure out.
But...If seating die setting is adjusted correctly, and you are still crushing necks then there is either a problem with internals of the seating die dimensions or...something bad wrong with neck sizing (or FL sizing) setting... wether it be brass thickness or bushing (or non-bushing) sizing, mandrel sizing or inside and outside chamfering... you have a problem that only precise measuring of equipment will figure out.
lancetkenyon
Well-Known Member
Why do you say that?
I have several sets of RCBS Comp seating dies, and have always used a standard shell holder with zero issues with multiple different rifles I load for, and with several brands of brass. Those are only if you are using short cartridges. .300RUM is definitely not a short case. I even use .260Rem RCBS Comp dies, and don't need to use an extended shell holder.
Well, if you look at the way they were designed you'll see that the Competition sizer is a standard shell holder, and the Competition seater is an extended shell holder, I own five caliber sets of them, and that the way they are used. I believe it's a #38 extended. https://www.artekcenter.com/rcbs-competition-extender-shell-holder-en/
This is the setting where the bushing in the die doesn't crush the shoulder.
The seater plug is covered up by the bushing when the ram is all the way up.
The Oregonian
Well-Known Member
If those measurements are correct, with .030 neck thickness and .308 bullet, that would put you are .338, with .002 neck tension that would give you an OD of .336.
Of course the loaded round is in reality what all that math should equal, and it sounds like that is .336.
Either way I don't think it should be rolling shoulders with the measurements you gave. There is something about those bullets that doesn't play nice with seating given that you could seat the Hornady ok.
Was wanting to see the seater stem adjustment ... the top of the die. No need really. I see we have covered pretty much all that would be the possible culprit without being with you to actually see it work.
FWIW... the other day I was chamber measuring a 6.5 with three different projectiles.
Two would almost fall in the modified case like normal while the Barnes Match Burner 145 would barely go in the neck!
I mean I had to push with my thumb hard enough that the plastic ram could barely push the bullet to the lands.
Had a hard time feeling the "touch".
The Alco measures a hair under .308". Don't have any more Hornadys to measure, but measured a 200 gr AccuBond and it was .307". That could be the difference. If anyone had some 212 ELDXs and could measure them, it would be interesting to see what they come out too. Now I'm kinda curious what all bullets are measuring. Since I always assumed bullets were .308".
Just measured (5) 212 grain ELDXs: (4) at .3075", (1) at .3080".
Don't have 212's but measured 6 208 ELDM : 4 @ .3075, 2 @ .3080
I did read your post, yes... I saw that it was a Gold Medal set when I saw your photos I was just thinking that perhaps an extended shell holder might work or help find the problem, I see that they do recommend the extended shell in some calibers with the Gold Medal seater... with that said; I've been using Competition die since they were introduced... The extended shell holder was designed as a guide to keep the case straight in the seating body and allow for length adjustment in multiple calibers, if you don't use them and standard works well for you, then I guess it's something else. I'm thinking you can always give RCBS a call (800) 533-5000 and get from the horse mouth as to what might correct the problem. Good luck.
RockyMtnMT
Official LRH Sponsor
I'm surprised I'm having issues with the Alcos than, maybe it's the HbN coating causing that much issue.
