Actually not really and it depends on resized case length.
- Semi-auto "max chamber length" is the distance between forward part of chamber with "ring step" that case mouth headspace off of (if the resized case is long enough) and the breech wall face of slide with extractor.
- As brass is fired and resized, work hardening along with case base expansion where resizing die, more specifically carbide sizer ring, do not reach causes the case to get shorter (roll sizing resizes all the way down to case base and case rim) and case gets shorter more times it is fired and resized which is why semi-auto cases are not trimmed. (This is why mixed range brass varies in resized length even though they may have started out at the same length ... For this reason, I measure samples of each headstamp and use longer resized case length to determine the "true" max OAL)
- So as resized brass gets shorter, it may no longer headspace off CASE MOUTH rather starts to headspace off EXTRACTOR - Picture case held by extractor with bullet nose/case mouth dangling freely at forward part of chamber ... When the firing pin/striker hits the primer, depth of indent on primer cup may be dependent on how tight the extractor is holding the case rim (I know, another myth busting thread in the making
)
No because semi-auto cases produce most of neck tension from resizing and less from taper crimp.
And without full-length resizing brass after each firing, especially if you shoot many pistols with different chamber dimensions and/or use mixed range brass fired from different size chambers, you risk getting finished round stuck in the chamber of your pistol barrel and not allow the slide to return to battery.
Unlike revolver bullets with roll crimp groove applied with case mouth (reason why revolver cases are trimmed to same length) , semi-auto bullets without crimp groove is mostly held by neck tension from reduction of case neck and less by taper crimp that digs into the bullet.
Since
most of neck tension (Friction from bullet base contact with case) comes from thicker wall further down from the case mouth that results in slight bulging of resized case neck (And this is why increasing taper crimp won't necessarily improve neck tension on semi-auto rounds), semi-auto cases need to be resized after each firing or you will have poor neck tension.
Not from me.
Since wall thickness averages .011" at case mouth, adding .022" to the diameter of the bullet will just return the flare back flat on the bullet and skosh more for thicker walled brass. So for .355" sized bullet, 377" taper crimp. For .451" sized bullet, .473" taper crimp.
Overcrimping bullets can reduce bullet diameter, cut into coating/copper plating, deform jacketed bullets and bulge case neck all of which can result in poor accuracy and/or leading of barrel along with finished round not fully chambering.
No. Bullet will not seat properly if tilted during seating. Sufficient flare amount will hold the bullet base steady so bullet can be seated straight without tilting (Indicated by one sided bulging of case neck on finished round that will make case neck oval/oblong). This applies to new and used brass.
No. If you can insert the bullet into the flare, it is too much (Unless you are using "M" die) as OP is using Lee press/dies.
I use just enough flare to SET THE BULLET FLAT on case mouth.
If you shave lead/coating when seating/taper crimping, consider these:
- Since mixed range brass vary in resized length, use shorter length case to set the flare amount so longer cases will apply more flare. If flare amount is set with longer length case, then shorter length cases will receive less/no flare and will shave lead/coating.
- Since mixed range brass vary in resized length, use longer length case to set the taper crimp amount so shorter cases will apply less taper crimp. If taper crimp amount is set with shorter length case, then longer length cases will apply more taper crimp and dig into the bullet base causing lead/coating shaving.
No. Semi-auto rounds that headspace off case mouth need to be taper crimped so case mouth can engage the "step ring" forward of the chamber and seal with the chamber wall to build pressure. Roll crimp will allow the chambered round to headspace off extractor and will delay sealing case mouth with chamber wall (Thinner brass wall at case mouth will expand faster than thicker case neck)
Roll crimp into bullets without crimp groove can cut into the bullet, coating, plating or jacketing which you do not want to do.
Yes. You can use the barrel to check resized brass to ensure they are full-length resized and finished rounds drop in and fall out freely to ensure they will feed reliably from the magazine.
No, case gage is not needed if you are only going to fire the finished rounds in your pistols. If you want to ensure the finished rounds will fully chamber in any SAAMI min/max barrel, then you need to use case gage. And if you get case gage for 380/9mm, you should get one for 45ACP too.
