CJP1 wrote:Hoot,
Thanks for the insight on the TNT. I thought it would be the end all to keeping bullets secure in the brass...snip....
So did I.
sigh...It's not a reach to realize that heavy crimping distorts bullets giving them a waspish figure. At least the cup and core ones. The less appreciated damage is what happens to the case mouths. The mouth is where the case wall is the thinnest. Repeated heavy crimping there thins them even more, leading to a vicious cycle or needing more crimp, causing more thinning, needing more crimp. causing more thinning, etc. the Thinning is not in leaps and bounds, like squeezing a rolled up ball of chewing gum but it does happen,
especially with solid copper or solid brass bullets. Its a cumulative effect. That's why any opportunity to crimp down into a driving band groove or cannelure is a saving grace.
Al, I seem to remember someone reporting on their experience with a 450b Factory Crimp Die right at the mouth.
I've also experimented with using a resizing die as a taper crimp. The reason you may have not noticed a report on that was despite doing the job, it provided no benefit that I could tell. Somewhere I have some target scans of the groups. IIRC, they were on par with groups provided by a taper crimp die. Certainly didn't help with velocity SD's either. Try the resizing die sometime yourselves. It works.
About the only thing I have yet to try is sealing compound like Markron sells. According to them, it doesn't effect pressure, so never felt like giving it a try.
Hoot