CrashDodson Posted January 5, 2016 Share Posted January 5, 2016 Been loading 40 for a while, just started loading 9 and noticed that the case dips in a little behind the bullet. Is this normal? The top of the case measures .3795 behind the bullet measures between .3750 and .3760. This is on a 550 with dillon dies. Link to comment Share on other sites More sharing options...
al503 Posted January 5, 2016 Share Posted January 5, 2016 9mm is a tapered case. Some refer this as the 'coke bottle' effect. What you're seeing is normal and actually a good thing in that it helps prevent setback. Link to comment Share on other sites More sharing options...
CrashDodson Posted January 5, 2016 Author Share Posted January 5, 2016 Thank you for your reply. I was looking at some factory ammo and did not notice the taper or at least not as profound and was worried I was doing something incorrectly. Thanks again. Sent from my SM-N920V using Tapatalk Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted January 5, 2016 Share Posted January 5, 2016 9mm is a tapered case. Some refer this as the 'coke bottle' effect. +1. Yup - all good. Link to comment Share on other sites More sharing options...
Yeti Posted January 5, 2016 Share Posted January 5, 2016 Looking good, Crash. Carry on. Link to comment Share on other sites More sharing options...
RDA Posted January 5, 2016 Share Posted January 5, 2016 Been loading 40 for a while, just started loading 9 and noticed that the case dips in a little behind the bullet. Is this normal? The top of the case measures .3795 behind the bullet measures between .3750 and .3760. This is on a 550 with dillon dies. Your dies are sizing down the case more than the bullet diameter. When you insert the bullet, it expands the case allowing it to hold the bullet firmly. The result is the "coke bottle" effect. You aren't seeing it on factory ammo as they don't size down the case as much as your dies do. Link to comment Share on other sites More sharing options...
9x45 Posted January 5, 2016 Share Posted January 5, 2016 Those look a little bulgy, but nothing to worry about. Whose bullets are those, what weight, what diameter? and what brass? Left to right, Bayou 124 TC (.3564"), Hornady XTP (.357") and Montana Gold JHP (.355") Link to comment Share on other sites More sharing options...
Beastly Posted January 5, 2016 Share Posted January 5, 2016 9mm is a tapered case AND the case steadily thickens as it approached the case head. Seating longer/heavier bullets more deeply will show an increasingly pronounced bullet bulge. Link to comment Share on other sites More sharing options...
CrashDodson Posted January 5, 2016 Author Share Posted January 5, 2016 These are 147 grain the red one is an ibijehead and the black one is from black bullets international. I would have to check at the house this evening for the bullet diameter. Link to comment Share on other sites More sharing options...
noylj Posted January 5, 2016 Share Posted January 5, 2016 If you are worried about it, use the expander die or, if you are, use a slightly larger expander die. The case ID after expansion should be 0.001-0.002" smaller than actual bullet diameter. If you use an expander and the ID is smaller than that, you should get a slightly larger expander. The only worries about what you have are: 1) if only on one side, it indicates that the bullet was seated crooked and the rounds may not chamber. Perform a "Plunk" test (do Google search if not familiar with term). 2) if using lead bullets, your lead bullets were probably swaged smaller when stuffed into an insufficiently expanded case and will be less accurate and may lead the barrel. Link to comment Share on other sites More sharing options...
CrashDodson Posted January 5, 2016 Author Share Posted January 5, 2016 Thanks for the replies. I case gauge each round and I have not had any issues. I use my barrel to gauge the rounds for matches. I just want to make sure I am being safe. These are minor loads but the case looked funny to me. I will check and see if the bulges are just on one side. I will load some tonight and check the diameter of the bullet first and the case after. Link to comment Share on other sites More sharing options...
CrashDodson Posted January 7, 2016 Author Share Posted January 7, 2016 ran some 9 tonight. The 147g bullets measure .3565 at the base. At the neck of a case after loading the case measures .3770 behind the bullet at the most narrow spot I can eyeball measures .3740. Link to comment Share on other sites More sharing options...
redneckram Posted January 18, 2016 Share Posted January 18, 2016 mine like the same its pretty common never had any issues Link to comment Share on other sites More sharing options...
rustybayonet Posted January 19, 2016 Share Posted January 19, 2016 Give it a chamber check and if it fits it ships. You may cause more stress on the case and they will wear out quicker. If bullet is centered in the case with no cracking of the case, just check dimensions should be NP. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now