147gr bulge 9mm question

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alank2

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Hi,

forgive my ignorance, it looks like the only the a case gauge does is measure case length before the bullet is seated? could i just do that with a pair of calipers since i dont have a gauge yet?

A case gauge can also be used to measure OAL by looking at how far the bullet protrudes past the end of it, but the big thing a case gauge does is makes sure the dimension of the cartridge are within tolerance. If your ammunition passes the case gauge, it should fit chambers great. Chambers are typically larger so if you use a chamber as a case gauge, it may or may not be in spec and may or may not fit another gun with a tigher chamber.

The Dillon stainless steel case gauges are about $12 or so and are awesome. It takes an extra bit of time, but I always check every round I make by running it through a case gauge.

9mm is an interesting cartridge in that it is not a straightwall cartridge, but a slightly tapered cartridge. Many die makers are darn lazy and given the price of carbide try to resize 9mm cases with a very small height carbide ring. The result is that these dies will "straightwall" a 9mm case. This means that some of the case is sized smaller than it should be. When the bullet is seated you will see the coke bottle effect. Again, as another posted indicated, the coke bottle effect is not a bad one other than looks because it will keep the bullet from setting back. It probably works the brass more and doesn't look as good, but 9mm cases are very strong.

I being the picky perfectionist that I am tried a few different 9mm sizing dies and found Dillon's 9mm size I liked the least. It had the smallest carbide ring and showed the worst coke bottled cartridge. Lee really surprised me because I expected the worst, but it came in 2nd best. They put a taller (but not full height) ring in there and it makes a big difference. The absolute best 9mm resizing die goes to Redding and their Pro set dies designed for progressive presses. Redding actually charges a price premium for this die. Why? Because it has much more carbide in it than their other dies because they designed it properly with a full height carbide ring to properly apply a resized taper to 9mm cases. I think the additional cost is something like $15 over their other die sets, so not a big cost.

I use Redding's pro set dies for every caliber I load and have never had any issues with them passing the case gauge or lacking case tension. The Redding dies are only about $10 more than Dillon's.

Good luck,

Alan
 

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