De-priming issues on .40S&W ...a Tip ..

BigJimP · August 2, 2010, 03:55 PM

I was running 1,000 rds of .40S&W late last week ....and in 1 in 4 cases, I started having a problem in station 1 ( de-priming some cases ). The de-capping pin was punching the primer out / but the pin was sticking into the primer cup - and then drawing it back into the case.

As the case went to station 2 - the spent primer was in the case / and I couldn't seat a new primer.

After 200 rds, I was way past frustrated ....

I called tech support / and found its apparently a common problem, with CCI primers for some reason. The solution / take the de-capping pin out of the die --- and take it to a grinder and sharpen it a little. Not so much that you would poke a hole in the primer / but enough that it doesn't have anything to hang onto.

I'm told they think - the higher pressure in the .40S&W rds / causes the primers to stick a little after detonation. I have no idea if that's true or not. I also pick up a lot of "range brass" - so I don't really know if its cheap ammo brass that was the issue or one of my own reloads / but I do use CCI pistol primers in my reloads.

I ran about 800 rds thru the press after I sharpened the pin / and they ran 100% with no issues. Just passing the tip on. A Note: the decapping pins in Dillon handgun caliber Dies - are all the same dimension / large pistol, small pistol ...makes no difference. I was using a Dillon 650 press / so maybe its only a problem on Dillon dies / maybe not ?? I have never had a problem in 9mm, .357 mag or even .44 mag .....( and I don't reload 10mm ...but it might be a problem there too ) ...but I shoot and reload several thousand rounds a year of 9mm, .45 acp and .357 mag especially.

Just trying to save someone else some aggravation ....Take care.

bullspotter · August 2, 2010, 05:00 PM

Thanks for the tip!! I have the same problem with decapping my 40 and 9 brass with cci primers, Using rcbs dies. Ill have to get the grinder out and give this a try!!

BigJimP · August 2, 2010, 05:08 PM

the pins are not hardened ...so even a stationary belt sander will work as well. I'd recommend pulling the whole die / or the whole stem inside the die / depending how your dies come apart ( so you have something to hold onto when you go to sharpen it ).

Just the pin alone is hard to hang onto at a grinder or sander...( one got away from me ...).

Dodge DeBoulet · August 2, 2010, 05:36 PM

I had the same problem with Hornady New Dimension dies in a LNL AP. I didn't do anything to sharpen the pin, though . . . I simply tightened it on its spindle. The issue really had to do with the "free floating" pin that allowed the spent primers to re-seat. Once it was tightened, the problem disappeared.

August 2, 2010, 03:55 PM	#1
BigJimP Senior Member Join Date: February 23, 2005 Posts: 13,195	De-priming issues on .40S&W ...a Tip .. I was running 1,000 rds of .40S&W late last week ....and in 1 in 4 cases, I started having a problem in station 1 ( de-priming some cases ). The de-capping pin was punching the primer out / but the pin was sticking into the primer cup - and then drawing it back into the case. As the case went to station 2 - the spent primer was in the case / and I couldn't seat a new primer. After 200 rds, I was way past frustrated .... I called tech support / and found its apparently a common problem, with CCI primers for some reason. The solution / take the de-capping pin out of the die --- and take it to a grinder and sharpen it a little. Not so much that you would poke a hole in the primer / but enough that it doesn't have anything to hang onto. I'm told they think - the higher pressure in the .40S&W rds / causes the primers to stick a little after detonation. I have no idea if that's true or not. I also pick up a lot of "range brass" - so I don't really know if its cheap ammo brass that was the issue or one of my own reloads / but I do use CCI pistol primers in my reloads. I ran about 800 rds thru the press after I sharpened the pin / and they ran 100% with no issues. Just passing the tip on. A Note: the decapping pins in Dillon handgun caliber Dies - are all the same dimension / large pistol, small pistol ...makes no difference. I was using a Dillon 650 press / so maybe its only a problem on Dillon dies / maybe not ?? I have never had a problem in 9mm, .357 mag or even .44 mag .....( and I don't reload 10mm ...but it might be a problem there too ) ...but I shoot and reload several thousand rounds a year of 9mm, .45 acp and .357 mag especially. Just trying to save someone else some aggravation ....Take care.

August 2, 2010, 05:36 PM	#4
Dodge DeBoulet Senior Member Join Date: December 8, 2009 Posts: 181	I had the same problem with Hornady New Dimension dies in a LNL AP. I didn't do anything to sharpen the pin, though . . . I simply tightened it on its spindle. The issue really had to do with the "free floating" pin that allowed the spent primers to re-seat. Once it was tightened, the problem disappeared. __________________ "You need only reflect that one of the best ways to get yourself a reputation as a dangerous citizen these days is to go about repeating the very phrases which our founding fathers used in the struggle for independence." - Charles Austin Beard

August 2, 2010, 05:00 PM	#2
bullspotter Senior Member Join Date: November 2, 2008 Location: Montana Posts: 308	Thanks for the tip!! I have the same problem with decapping my 40 and 9 brass with cci primers, Using rcbs dies. Ill have to get the grinder out and give this a try!!

August 2, 2010, 05:08 PM	#3
BigJimP Senior Member Join Date: February 23, 2005 Posts: 13,195	the pins are not hardened ...so even a stationary belt sander will work as well. I'd recommend pulling the whole die / or the whole stem inside the die / depending how your dies come apart ( so you have something to hold onto when you go to sharpen it ). Just the pin alone is hard to hang onto at a grinder or sander...( one got away from me ...).