The only issue that I have with 429 is random ejection angle... this is caused by the case being necked down. As it is extracted, as soon as the neck passes, the case starts to "eject". Because there is another 3/8 or so of case left (the neck) the shell begins its "flip" out of the chamber 3/8's early and the neck hits the barrel extension lug area causing it to eject in random directions... including your head sometimes. I almost always wear safety glasses anyway, but with this caliber, it is very important to do so.
When I get a 10" 429DE Barrel I will chronograph them right off and post the results.
I still want a 50AE necked down to a 357 though.
MrBlackCat