So, WHY does the Star "Pop" when sizing .452s but NOT .3575s???

[Grump]

Just switched back to the .45 sizer and was reminded of that cute little "pop" noise it makes when the sized/lubed bullet falls out the bottom.

Forgot about it because the .38s I was doing before weren't making that noise.

Now I expect it right after change-over because of the air getting it, but it sure seems like after 200+ sized and lubed any and all air in there should be gone. Plus the factor that it wasn't doing it with .38s...

So, anyone know what's up??? It's not a problem, just a curiousity.

[376Steyr]

Air is getting compressed between the bullet in the bottom of the die and the one coming in. As for why 45's pop and 357's don't, I'll go with the 45's are compressing a greater volume of air. Differences in the nose shapes, bullet length, punch depth, etc. would affect the volume of air being compressed too.

[Grump]

Ah, makes sense!

The stem doesn't seal the sizing bore, but the next bullet sure does. The two bullets involved have a big difference in volume outside the nose cone (or at least it appears) and perhaps more importantly, the .38s stick up more in the "static" position (closer to the opening of the die, reducing the effective compression ratio.