Everything mentioned is assuming the ruger chamber was in spec. Seems odd all these cases Measures out with SAAMI and cleared a case guage as well. Yet you then have it stared that cases would not fully seat into the FL die? For a case head to be that expanded (range pu) I have trouble seeing it coukd be in SAAMI spec.
My guess is a few of those range pickups did not go fully into the die but instead the D550 plate flexed and somehow it got missed with the case guage unless the gauge is overly generous. The other option is the ruger chamber is tighter than spec. How else could you load those cases on your Dillon yet now upon rechecked and trying to size them again they will not even force into the die? Maybe I am not mis interpreting what was stated here:
I have checked EVERY hand-load round for case specs, overall length, and bullet diameter with caliper and case gauge. I did find a few that the head size was at the 0.376” and tried to resize them. They didn’t want to resize in the Dillon die (tended to stick and didn’t want to have one stuck in my die so discarded them)
So these were already handloaded so loaded rounds. Yet upon pulling them apart and trying to resize in the Dillon die they would not go in under reasonable handle force? So then how did they get loaded and go thru the die in the first place? My guess would be plate flex or something was missed. That would also mean only a partially sized case neck as well and possibly no shoulder bump so a lengthened case. Just speculating more than anything your process so you can address it going forward. First is any range pu needs to be kept separate or better yet left where you found it on the range. That $0.40 cost you a day at the range, the cost of the components. The time rechecking everything, the gunsmith fees, the shipping to ruger and weeks without your gun. That was possibly a very expensive savings LOL. It's all a learning experience.
No SB die is going to fix this kind of issue with pu range brass or any brass where the case head is blown out so far it would take tremendous force to get it into the sizing die. It can though split/crack dies or in a progressive press bend/warp parts. The SB die does can of course help if it's a progressive expansion and used in first few firings or from the get go. This assumes you not shooting over pressure loads and blowing out the case heads.
A case not having its shoulder pushed back far enough (no head clearance) alone also would not cause this issue. If that was happening the case would not allow the bolt to lock but it would still extract as its a length not a diameter issue. Given the case was visibly stuck sticking partially out of the chamber points to a diameter interference issue especially given it was tight enough a screw driver prying could not dislodge it. Wrong way to dislodge case BTW.
The OP should have mentioned the range pu brass. Regardless a case that passes a case guage test but then jams chambering with a ¼ left sticking out........some dimension is either off spec in the chamber (least likely) and or case guage (almost as unlikely) or not every case was actually properly checked on the case guage and not properly sized (most likely especially if my speculations above end up being correct)
While I agree perfectly in spec, good quality, sub moa ammo can be produced on a Dillon 550, BTDT many times. It is also true as was stated that there is alot more going on at once with 5 stations vs a simple single stage press. It's much easier to catch things. Take feel/force on the press handle cycling. On a single stage you know exactly where a change is coming from. That one specific case you are sizing or bullet seating etc. On a progressive is it the sizing? The primer decapping? Bullet seating any combination of them? i What? It's all happening on that one stroke. Not to mention your attention which is usually on the bullet seater if you are hand positioning the bullet
To remove a jammed loaded round. Remove the bolt/bcg. With barrel (BOTH ENDS) pointing in safe directions and be standing well off to the side. Place a wood dowel rod down the bore from the muzzle. Then starting with very light taps progressively with more force with a mallet. The better way if you have time and a deep freeze is pull the upper and put it in the deep freeze for a few hours then do the same dowel rod procedure. Brass contracts/expands more than steel with temp change. With a standard Dillon die and add in crimping it's very likely even a hard whack would not set back the bullet at all. The danger is the bullet and case acting as a fire piston creating compression thus heat igniting the powder. A bit of common sense goes a long way here.
. I have a Very Light crimp (about 1/8th of a turn on the crimping die), just enough to feel some resistants on the very last bit of the stroke. I have checked as best I can with the calibrators against Factory rounds and mine. I do understand about HIGH pressure due to heavy crimping. Haven't seen any signs of it on my brass or durning resizing.
