45acp: Crimping to pass the 'plop' test without resizing the cast bullet


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777funk
February 15, 2013, 05:50 PM
I've been reloading cast SWC's and they're fitting a little bit on the tight side in the chamber in a P90. They don't pass the plop test and at times the slide won't close fully. I can push the slide shut with a little help... but that takes the auto out of auto loader and in any competitive shooting, I'd have trouble using this method!

Anyways, to my question. I can take the barrel out of the gun and plop factory ammo and dump it right out easily. Not so with the cast reloads.

Lee tells me I need an extra step and their factory crimp die. But I don't want to resize the cast lead bullet either. Is there a way around this?

Can I crimp the round to pass the plop test with the 3 die set I now have? Supposedly the last step is a Crimp/Seating die.

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rcmodel
February 15, 2013, 06:03 PM
Can I crimp the round to pass the plop test with the 3 die set I now have?Yes, thats what the seating & taper crimp die is for.

Assuming you are using .452" lead bullets?

Depending on your brass thickness?
Adjust the die so the case mouth crimp measures .471" - .472" and you should be good.

.451" jacketed bullet crimp should measure .469" - .471".

SAAMI Max is .473", so unless your chamber is excessively tight, .472" taper-crimp should fit without squishing the bullets.

rc

777funk
February 15, 2013, 07:06 PM
Yes, thats what the seating & taper crimp die is for.

Assuming you are using .452" lead bullets?

Depending on your brass thickness?
Adjust the die so the case mouth crimp measures .471" - .472" and you should be good.

.451" jacketed bullet crimp should measure .469" - .471".

SAAMI Max is .473", so unless your chamber is excessively tight, .472" taper-crimp should fit without squishing the bullets.

rc
Thanks RC. It seems like the crimp/seating die is kind of mashing the brass a bit. It doesn't look too good. Could I be doing it wrong? I assume the way to set the die for a crimp is to dial it down to the empty case height then dial it another 1/8 to 1/4 turn further?

beatledog7
February 15, 2013, 07:24 PM
You might be crimping too much. In my experience, with most lead bullets in semi-autos, the proper amount of crimp requires little more pressure than the weight of the press handle.

bds
February 15, 2013, 08:13 PM
I would also double-check the OAL to make sure the shoulders of the SWC bullets are not hitting the start of rifling.

Even for tight chambered Sig 1911 TacPac barrel, I can get .452" sized 200 gr SWC lead loads to drop in freely.

I use Lee dies and seat/taper crimp in the same step. Depending on the length of leade/free bore, you may need to shorten the OAL.

I use .473" taper crimp (.452" + .021" ). Any more and they won't fully chamber. If you seat and taper crimp in the same step, using less than .472" taper crimp may cause the case to shave the side of the bullet.

I do not use the FCD for 45ACP lead loads.

Rule3
February 15, 2013, 08:34 PM
Don't forget that when you seat and crimp with the Lee seating die when it crimps it also will seat the bullet a fraction more, can't remember what the exact amount is. So when you set your OAL set it a bit long then turn the die to crimp.

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