Okay. Your bullet sizer might have scraped the lead off to achieve the proper size. Mine didn't (Lyman). The die entry was beveled to prevent this and it only compressed the bullet to get the correct diameter.The bullets I use in both .356" and .357" sizes are identical - they have what looks like a crimping grove and just a hair above that, the nose tapers up to a flat point. As I said, I don't know what Dardas bullets look like.
If the bullets are sized in a sizing die that basically scrapes the bearing surfaces down to the desired size as the ones I used to own when I was casting my own bullets did, a .355" bullet will weigh less than one sized to .356". The .356" 125-grain bullets I use weigh almost right on 125 grains but their .357" counterparts weigh a little more but not over 125.5 grains so they still are called a 125-grain bullet. I don't have any of the 124-grain ones on hand to check.
Actually, the .357 SIG shoots a 9mm bullet (.355).I didn't check Dardas' website to confirm this, but most 124-grain bullets are sized smaller than their 125-grain counterparts, which accounts for the "lost" grain of weight. I usually use Missouri 125-grain IDP #6 lead semi-wadcutters in my .38 Super. They are sized to .356" but I recently looked at some Precision Cast 124-grain lead semi-wadcutters that appear to be cast with the same mold and found they are sized to .355", which is the preferred size for a 9mm, I believe. Hunter Supply sells an identical-looking bullet sized to .357" for the .357 Sig.
Thanks for the links, very informative site sir.Our best guide for when you're gone too far is if you exceed published load data. Seriously, we have limited tools in that respect. Our next best guide is pressure signs in the primers, but several factors can influence this, and they are a poor guide at best. But, in general, a good rule of thumb is that if you see pressure signs in the primers, you've gone too far. The one clear exception to this is the Remington 1 and 1/2 primer, which is not designed for high pressure and can show excess pressure signs even though you are within SAAMI pressure limits. Excess bulging in the brass is another clue, but this generally applies to chambers that don't fully support the case. Velocity is a poor guide since velocity can vary from one gun to another even if they are the same brand with the same barrel length. Recoil is a poor guide since what do you compare it too? A kaboom is a great guide, for obvious reasons!
You can see pressure signs in primers and brass at the first link below, and specific information about different primers at the second link, which just happens to have looked at 231 and a 124 grain bullet in the 9mm Luger.
Temper, I think I have the same question as you.... Really, what is the difference (besides a little shape and 1g), does it matter? To those that have shot both, what did you think?Dardas offers both weights in LRN and the ogive appears the same. Is there a reason both weights are offered?