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So I realize this isn't cast bullets per say but you guys have more knowledge than most of the internet I would say. My issue is I want to use these 9mm bullets which are FMJ without a cannelure. I don't know how I should go about crimping them. They will be used in a KP9 which is a AK style rifle and I want to avoid setback in the casing. Can I use my LEE factory crimp die even when there is no cannelure?
Attachment 301622
A Lee factory crimp die applies a taper crimp, not a roll crimp. Having a cannelure really has no effect on a taper crimp. Think of it as applying enough tension on the case mouth to secure the projectile. Hopefully this helps and makes sense.
Because it isn't a revolver cartridge the FCD is taper and not rolled? I though the seating die had the taper crimp option to it. Now I'm confused moreQuote:
Originally Posted by poppy42
Your sizer die will reduce the case diameter to be undersized to the bullet. The expanding die should only expand the case mouth to the depth matching the base of the bullet you are going to use as well as maintaining neck tension. The crimp die is only supposed to remove the case mouth flare. Any "extra" crimp might be negated by the brass case spring back.
FYI-- I tried those SIG bullets last month, and the result was too short to reliably feed in two of my 9mm semi-autos. Might work for you....
DG
What was the max OAL you could get?Quote:
Originally Posted by Der Gebirgsjager
I didn't measure them, just seated them up to the base of the expansion slots. Mine were 115 gr. I reordered and got 124 gr. and they work well. I'm thinking that the ones in your photo might be for .380 ACP.
DG
Those sure look like the 90gr bullets to me.
YesQuote:
Originally Posted by CZbob9
Generally any bullet that size with a cannelure would be for .38/.357. Most 9mm bullets do not have a cannelure. The Lee FCD for 9mm should be a taper crimp.
Read the instructions that came with the Lee Factory Crimp Die you say you have.Quote:
Originally Posted by CZbob9
I believe it will give you the answer you are seeking.
9mm cases headspace in the pistol on the mouth-- that is, the front of the case hits the little step in the barrel. What that means is that the crimp on a 9mm is just enough to leave the case straight-- not smaller than the bullet. You expand the mouth slightly to let the bullet be seated, then straighten it with the crimp-- but not smaller. That's why there is no cannelure.
No, seating dies usually put on a roll crimp.Quote:
Originally Posted by CZbob9
My best results have been with doing a taper crimp done as a separate step with its own die.
Hornady makes one they claim seats and does a taper crimp in one step---
but it will take someone a whole lot smarter than me to make it work right.
There are some brands of seating dies that taper crimp in the seating die, assuming that the caliber is generally taper crimped. RCBS and Hornady for sure. Dillon I think. They can be fiddly to set up, and like you, I prefer to taper crimp as a separate operation.Quote:
Originally Posted by Winger Ed.
Seating dies for revolver calibers that index on a rim instead of a case mouth generally roll crimp in the seating die. If I happen to have a spare taper die I’ll use it, but I’m happy to seat and roll crimp in one operation.
Dillon pistol seating dies don't crimp. They have a separate crimp die in their 3 die handgun sets. The 9mm Lee Carbide Factory Crimp Die crimps no differently than other taper crimp dies.
Best way to prevent setback is through good neck tension. On that short bearing surface a heavy taper crimp can make matters worse because it squeezes the bullet down and brass springs back somewhat. Notice how easily a heavily taper crimped round plops out with a kinetic puller.
Best strategy for getting good neck tension is to ensure that the shank of the expander is 2-3 thousandths less than bullet diameter. Then sort for brass with the thickest neck walls (e.g. R-P and CBC). Avoid the thin stuff like FC, Speer, and Blazer and reserve those for plus-sized cast bullets. If you can see the edge of the bullet heel making a little ring in the brass, congrats, you have good neck tension.
EDITED TO ADD A PIC
Here is a short 90 gr .355 bullet seated into a CBC case. .352" expander. See the line where the heel is bulging out the case a bit. That inidicates that substantial seating force will be required to move it deeper. The key is the thick brass. It is crimped just enough to remove the bell. After seating, push the nose hard into the bench. If it doesn't budge, good neck tension.
https://i.postimg.cc/0yGgRjkL/20220629-210156.jpg
Seating and crimping should be done in separate operations.
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The ram always travels, so the bullet always moves when seating & crimping in one step, which causes the case mouth to scrape the bullet while the crimp is formed. There are some exceptions, but I say always seat & crimp in separate operations. A scraped bullet will have weaker neck tension and reduced accuracy.
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Over-crimping can lead to a weaker connection and more bullet set-back.
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The comment about brass bulging around the bullet is great. Just make sure the loaded round fits inside your barrel.
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If you still have issues, wash your brass with a 2:1 ratio of water:lemon juice (rinse with a few drops of dawn dish soap and hot water). I have found this to increase the coefficient of friction, which reduces bullet set-back.
I find that measuring the case neck diameter after crimping is not reliable. Instead, I place the finished round between jaws of a set of calipers and see where the light is coming through. Also, if you are under crimped then the jaws will contact the case mouth.