setback, loose bullets

PowerPistol · June 14, 2013, 10:44 AM

I have some .40S&W that I loaded up before I discontinued using the Lee FCD. Some of them I can ( with a fair amount of pressure ) push the bullet deeper into the case. My question is, as long as i dont rechamber these rounds multiple times, are they safe to use?
Is there anything else in the normal operation that would cause bullet setback if the neck tension is insufficiant?

PP

g.willikers · June 14, 2013, 10:53 AM

Have you tried adding a little more taper crimp with the normal die?
Too much flare on the case can add to the problem.
Sometimes they can expand back out after the crimp is applied.
Loose bullets can be pushed into the case a number of ways.
Hitting the front of the magazine during recoil and hitting the feed ramp, for example.

totaldla · June 14, 2013, 11:20 AM

Bullet setback can seriously raise pressures and blow out a case, so it isn't something to ignore with the 40S&W. Some cartridges are more forgiving, but not the 40. So I would do a couple of chamberings (let the slide slam it home off the magazine) and measure the OAL. If it moves .010" with one chambering, I would consider pulling them down. I don't know your load and have no idea of your margin.

The 40S&W is a straight-walled case and the neck tension established by the resizing die provide 99% of the bullet holding power. But certain brass (thin) & bullet (undersized) combinations can result in less neck tension than necessary. Taper crimp really only aids feed reliability and too much taper crimp can actually reduce neck tension. My point here is that there are a couple variables you need to address to make sure this condition doesn't happen in the future.

So the first thing to do is back off your taper crimp and check the holding power. As a last resort you can modify your resizing die by sanding the expander plug down .001".

mikld · June 14, 2013, 11:52 AM

Normally case mouth flare will only go 1/16" or .060" or so deep in the case mouth. Neck tension is determined by bullet diameter, case wall thickness, and resizing die/expander. If you have loose bullets it's more than likely one of these (not counting overcrimping). Start with the easiest first, measure the bullets and the expander plug. Jacketed bullets seem to mostly be .400"-.401". Your expanding plug should be a few thousandths smaller (.002"-.003").

Load some or make up a dummy and don't crimp, just size case and seat bullet. Check for bullet tightness.

If that doesn't help, sort brass by headstamp and if you can measure the wall thickness at the mouth (I've not had a problem with case thickness affecting reloading in any handgun cartridge I've ever reloaded). Mebbe you're getting some thin brass and could try another manufacturer.

I've rarely had this problem, and don't think you'll have to go through all the stuff above, but it'll usually be one of them screwing up the neck tension.

PowerPistol · June 14, 2013, 12:18 PM

Actually, it has nothing to do with crimp. It is caused by the LEE FCD. They are fine until run through that die. I have tested and confirmed this. That is why I dont use it anymore. These are lead bullets by the way.

Old Stony · June 14, 2013, 12:35 PM

Perhaps I misunderstood the previous post about a Lee factory crimp die. I don't understand how it can leave a bullet loose in the case. I have used them for years and never had a problem...with the only exception is I have always used an RCBS taper crimp die on .45 acp. Hitting the feed ramp can jam a bullet back into the case and cause the afore mentioned dangerous situation. I would either put a proper crimp or discard them.

Nathan · June 14, 2013, 12:58 PM

With this issue, I would pull them.

For those of you attributing this to the Lee FCD, I think you are not getting the engineering or that die was grossly out of spec. It is just supposed to nock off extra lube or a slight bullet buldge due to misshaped cast bullets. It is a guarantee and not supposed to size on every round.

totaldla · June 14, 2013, 03:54 PM

The problem isn't the Lee FCD. The problem is how he is using the Lee FCD. The FCD is capable of grossly over-crimping and most certainly will destroy neck tension. Standard taper-crimp dies can do the same thing - it is just harder.

jim8115 · June 14, 2013, 07:43 PM

"The problem isn't the Lee FCD. The problem is how he is using the Lee FCD. The FCD is capable of grossly over-crimping and most certainly will destroy neck tension. Standard taper-crimp dies can do the same thing - it is just harder. "

No, even if i dont use the FCD to crimp at all, it will loosen some bullets. Thats is why I dont normally use it anymore. Some brass is worse than others.

mikld · June 14, 2013, 08:10 PM

Actually over-crimping can distort the case wall and loosen the bullets. Common with new reloaders using FCD (!) and taper crimp dies and not understanding neck tension and/or semi-auto cases do not need crimping...

57K · June 14, 2013, 08:14 PM

It is an established fact that the LEE FCD can resize bullets where brass thickness may be greater in some cases than others. Typical taper crimp dies only act on a minimum depth on the case-mouth where the FCD acts more like a sizing die. I don't use them or recommend them.

Having said that, I would pull the bullets that are slipping. Set back is a potentially dangerous in even small amounts. Too much and considering the questionable case-head strength of the .40 S&W, it could be an invitation to a Ka-Boom event.

June 14, 2013, 10:44 AM	#1
PowerPistol Member Join Date: January 7, 2013 Posts: 16	setback, loose bullets I have some .40S&W that I loaded up before I discontinued using the Lee FCD. Some of them I can ( with a fair amount of pressure ) push the bullet deeper into the case. My question is, as long as i dont rechamber these rounds multiple times, are they safe to use? Is there anything else in the normal operation that would cause bullet setback if the neck tension is insufficiant? PP

June 14, 2013, 10:53 AM	#2
g.willikers Senior Member Join Date: September 28, 2008 Posts: 10,442	Have you tried adding a little more taper crimp with the normal die? Too much flare on the case can add to the problem. Sometimes they can expand back out after the crimp is applied. Loose bullets can be pushed into the case a number of ways. Hitting the front of the magazine during recoil and hitting the feed ramp, for example. __________________ Walt Kelly, alias Pogo, sez: “Don't take life so serious, son, it ain't nohow permanent.” Last edited by g.willikers; June 14, 2013 at 10:59 AM.

June 14, 2013, 11:20 AM	#3
totaldla Senior Member Join Date: August 10, 2009 Location: SW Idaho Posts: 1,294	Bullet setback can seriously raise pressures and blow out a case, so it isn't something to ignore with the 40S&W. Some cartridges are more forgiving, but not the 40. So I would do a couple of chamberings (let the slide slam it home off the magazine) and measure the OAL. If it moves .010" with one chambering, I would consider pulling them down. I don't know your load and have no idea of your margin. The 40S&W is a straight-walled case and the neck tension established by the resizing die provide 99% of the bullet holding power. But certain brass (thin) & bullet (undersized) combinations can result in less neck tension than necessary. Taper crimp really only aids feed reliability and too much taper crimp can actually reduce neck tension. My point here is that there are a couple variables you need to address to make sure this condition doesn't happen in the future. So the first thing to do is back off your taper crimp and check the holding power. As a last resort you can modify your resizing die by sanding the expander plug down .001". __________________ Lee Auto Bench Prime Castor Oil Case Lube

June 14, 2013, 11:52 AM	#4
mikld Senior Member Join Date: February 7, 2009 Location: Southern Oregon! Posts: 2,891	Normally case mouth flare will only go 1/16" or .060" or so deep in the case mouth. Neck tension is determined by bullet diameter, case wall thickness, and resizing die/expander. If you have loose bullets it's more than likely one of these (not counting overcrimping). Start with the easiest first, measure the bullets and the expander plug. Jacketed bullets seem to mostly be .400"-.401". Your expanding plug should be a few thousandths smaller (.002"-.003"). Load some or make up a dummy and don't crimp, just size case and seat bullet. Check for bullet tightness. If that doesn't help, sort brass by headstamp and if you can measure the wall thickness at the mouth (I've not had a problem with case thickness affecting reloading in any handgun cartridge I've ever reloaded). Mebbe you're getting some thin brass and could try another manufacturer. I've rarely had this problem, and don't think you'll have to go through all the stuff above, but it'll usually be one of them screwing up the neck tension. __________________ My Anchor is holding fast! I've learned how to stand on my own two knees...

June 14, 2013, 03:54 PM	#8
totaldla Senior Member Join Date: August 10, 2009 Location: SW Idaho Posts: 1,294	The problem isn't the Lee FCD. The problem is how he is using the Lee FCD. The FCD is capable of grossly over-crimping and most certainly will destroy neck tension. Standard taper-crimp dies can do the same thing - it is just harder. __________________ Lee Auto Bench Prime Castor Oil Case Lube

June 14, 2013, 12:18 PM	#5
PowerPistol Member Join Date: January 7, 2013 Posts: 16	Actually, it has nothing to do with crimp. It is caused by the LEE FCD. They are fine until run through that die. I have tested and confirmed this. That is why I dont use it anymore. These are lead bullets by the way.

June 14, 2013, 12:35 PM	#6
Old Stony Senior Member Join Date: May 31, 2013 Location: East Texas Posts: 1,705	Perhaps I misunderstood the previous post about a Lee factory crimp die. I don't understand how it can leave a bullet loose in the case. I have used them for years and never had a problem...with the only exception is I have always used an RCBS taper crimp die on .45 acp. Hitting the feed ramp can jam a bullet back into the case and cause the afore mentioned dangerous situation. I would either put a proper crimp or discard them.

June 14, 2013, 12:58 PM	#7
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,331	With this issue, I would pull them. For those of you attributing this to the Lee FCD, I think you are not getting the engineering or that die was grossly out of spec. It is just supposed to nock off extra lube or a slight bullet buldge due to misshaped cast bullets. It is a guarantee and not supposed to size on every round.

June 14, 2013, 07:43 PM	#9
jim8115 Senior Member Join Date: July 23, 2011 Location: Arkansas Posts: 229	"The problem isn't the Lee FCD. The problem is how he is using the Lee FCD. The FCD is capable of grossly over-crimping and most certainly will destroy neck tension. Standard taper-crimp dies can do the same thing - it is just harder. " No, even if i dont use the FCD to crimp at all, it will loosen some bullets. Thats is why I dont normally use it anymore. Some brass is worse than others.

June 14, 2013, 08:10 PM	#10
mikld Senior Member Join Date: February 7, 2009 Location: Southern Oregon! Posts: 2,891	Actually over-crimping can distort the case wall and loosen the bullets. Common with new reloaders using FCD (!) and taper crimp dies and not understanding neck tension and/or semi-auto cases do not need crimping... __________________ My Anchor is holding fast! I've learned how to stand on my own two knees...

June 14, 2013, 08:14 PM	#11
57K Junior member Join Date: March 2, 2013 Location: Heart of Texas Posts: 788	It is an established fact that the LEE FCD can resize bullets where brass thickness may be greater in some cases than others. Typical taper crimp dies only act on a minimum depth on the case-mouth where the FCD acts more like a sizing die. I don't use them or recommend them. Having said that, I would pull the bullets that are slipping. Set back is a potentially dangerous in even small amounts. Too much and considering the questionable case-head strength of the .40 S&W, it could be an invitation to a Ka-Boom event.