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Posted: 1/17/2017 8:52:16 PM EDT
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I usually load 9mm using JHPs for competition, last November while I was casting up a bunch of 158 gr SWC I also cast a couple hundred 124 TC to give lead a try in my 9mm, at least for 25 yards and in practice. I decided to try powder coating at the same time. My .38 test ammo is ready to go so I was starting on my 9mm stuff.
I loaded four test dummy rounds to see if they would cycle in stock Springfield by hand. The shortest round had the transition of the driving band and truncation flush with the case and the others were each slightly more proud. OAL were 1.0944", 1.1185", 1.1225" and 1.1285". These projectiles were PC'd with HF Red. All four rounds fed, chambered and ejected so at least I've got that going. After checking for function I thought I'd check and see if the bullets set back in the cases any under hand cycling and that's where it gets interesting. The two shorter rounds set the bullet back .0010" in one cycle through the gun (I suppose that could have happened when the rounds hit the floor too) but the two longer rounds actually got longer. The 1.1225" grew to 1.1230" and the 1.1285" grew to 1.1295"! Both of the longer rounds have nicks in the powder coat right at the transition of the driving band and the truncated cone. I suspect the longer rounds may be engaging the rifling enough to pull the bullet out .0005 to .0010" upon extraction. Does that sound right to y'all? I should probably repeat the test with my modified comp gun and see if the results are similar, maybe even protect the extracting rounds to remove that variable. Based of this first test it looks like my first live rounds will be at the 1.1185" OAL. |
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I use the Lee 120 gr Truncated Cone in 9mm.
I noticed 2 things once I started to powder coat them. 1) Had to shorten OAL, because bullet was sticking in the rifling. CZ-85 2) Had to increase the bell, in fact I went to a M die to keep from using the large bell the conventional bell die needed. My pistol will not chamber bullets sized larger than .356. But that's a CZ thing. So load to suit your pistol. |
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Interesting on having to load shorter. I ran these through my custom 6" and found only the shortest would work, the other three pulled the bullets out almost .004" on extraction. If I keep them short I should be able to use these for practice in all of my competition 9mm 1911s.
I have sized these to .358", which should run fine in my guns. Both of my .358" sizing dies size down to .3575" (RCBS die in the Lubrisizer and the Lee push through sizer). Now that I have a working OAL I can start working up a load. |
It all sounds good to me. I size all my powder coated .38s and 9mms .358" I haven't found a 9mm that didn't shoot them well yet. (Don't have any CZ's  )
All I use is HF red too. At some point you should try the truncated cone 9mm in your .38spl or .357 they make a nice plinking load. I have the tumble lube mould. I roll crimp in the first groove below the cone. Motor |
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Quoted:
I recently loaded some coated 124 TCN 9mms from Bayou. I need to seat them pretty deep (1.080-1.090) in order for them not to engage the rifling in my CZ SP01. 124 RN from Bayou can be seated at 1.14-1.15 to pass the plunk test in the same CZ. I've only played with a few cast bullets in 9mm but the few I have played with needed to be seated fairly deep or they would stick in the rifling or not chamber. I could see how the coating would further multiply this. I always use the barrel I'm going to shoot them from as a case gauge (have way to many rounds I need to pull because I didn't plunk test. so bad I thought of buying a 9mm Blackhawk to use as a "bullet puller"  ) lol have almost half a 30 cal can worth. you can mess up in a hurry on a progressive.
as long as you don't have feeding issues I wouldn't worry about the short coal. I look at it as a bonus as you use less powder. |
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The numbers you posted about the bullets pushing in or pulling out are, quite literally, NOTHING. You're talking about half of one thousandth of an inch to one thousandth of an inch. You'll get that variation by the amount of thumb pressure used or measuring in different places. You could measure the same cartridge 10 times and get 10 different readings that vary by that much. Calipers are not made for such small tolerances, we use them because they will get us close, and that's ''good enough''.
Your bullets are not moving, don't worry about them. Just get the length where they will fit, chamber and function and you'll be good to go. ETA: Forget about that 4th number after the decimal point, it is so small it means nothing to us. |
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