9mm bullet seating question - newbie

[Endoz]

Newbie here, just got into reloading, loaded 124grn Rainier plated round noses w/ 3.8gr titegroup. I'm at 1.155 OAL. w/ little to no crimp marks on bullet when i pull them to look. My question is, If i grab a cartridge (without powder) and take pliers to the bullet, i can pry it back and forth and it will come out without too much trouble. I CANNOT twist them.  

Likewise, when I use a kinetic bullet puller, it only takes 2-3 whacks to drop the bullet out. Realizing this isn't very scientific, does it seem like i have not enough crimp on bullets?

If I put anymore crimp on bullet it wants to leave a line where brass hits so i backed it off slightly. I using a progressive Dillon so used their manual/dvd as reference and referenced Lyman manual as well. 

I test fired around 30 and they were accurate and no problems. That said I didn't take calipers to rounds in magazine after i fired a few shots to see if they were changing OAL. 

Appreciate any insights,

Endoz

 

[bandw1dth]

See if their changing OAL and if not then just load them up and go shoot.

As a general rule I measure case wall thickness right at the mouth, multiply by two and add that to bullet diameter to get my crimp. Then just adjust die till you get that number and you should be good. If I'm understanding you right, your should already be right about there.


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[Endoz]

15 minutes ago, bandw1dth said:

See if their changing OAL and if not then just load them up and go shoot.

As a general rule I measure case wall thickness right at the mouth, multiply by two and add that to bullet diameter to get my crimp. Then just adjust die till you get that number and you should be good. If I'm understanding you right, your should already be right about there.


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never thought of using math, thanks! I'll test some more to see if their changing during firing. 

[hceuterpe]

It's not so much a problem that the bullet pulls out with force. Rather that it gets pushed into the case (setback). That lowers OAL which increases pressure.

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[itzjere]

http://dillonprecision.net/crimp-calculator/

 

[Endoz]

Very helpful calculator thanks!

[Southpaw]

Take one of your loaded rounds and put the bullet tip against the side of your workbench.  Put your thumb on the bottom of the case and push hard on the round trying to push the bullet into the case, then re-measure OAL and see if there's any setback.  You can also try chambering the same round a couple times and check for any setback.  If no setback in these tests then you have sufficient neck tension.

[Endoz]

According to that calculator i'm at 0.376 - 0.377 or moderate to light crimp. Assuming rnds don't change OAL during firing i'm going to call that good. 

Thanks all

Endoz

Moderate Crimp__(.003)  0.376

[bandw1dth]

I'm curious to see how the various crimps work with coated rounds.


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[Endoz]

Went to range today with no problems, measured OAL several times from rnds in magazines and all fine. Did Dot Torture drill at 7 yards and rounds were accurate. Did notice a fair amnt of powder residue on casings, using titegroup. 

[Sarge]

You are getting some good and some bad info here. Crimp in a straight walled case has virtually no effect on bullet tension UNLESS you way over do it in certain instances.

 The only thing to worry about right now is setback. To test that just push the round against the bench hard with your thumb. If it shortens by clearly sinking the bullet deeper then you worry. Adjusting crimp wont help. You have a sizing issue instead. Make sure your sizer is kissing the shell plate. If it already is then try a LEE die first. If that doesnt totally cure it then get an EGW/LEE undersized die. My dillon die sucked at preventing setback so i quit using it.

FYI I use a UDIE and i can pop a bullet out in one smack of the puller if i do it right. But that all depends on the surface you use etc.

edited to add black sooty cases with TG means weak ass loads not sealing the case in the chamber. 3.8 with a 124 is pretty limp. Bump it to 4.0 and see if it gets cleaner

Edited November 11, 2016 by Sarge

[MemphisMechanic]

What Sarge said.

Think of crimp as "flare removal" for the case mouth and nothing more. You are not crimping the bullet into place in a 9mm cartridge, and trying to do so is a recipe for inaccurate rounds or feeding issues.

Get the case walls straight again and get them to gauge 100%, and go no further.

What holds the bullet in place is case mouth tension - the brass was undersized in the first die, and then forced to stretch around a bullet as it was seated. That tension is your clamping force. The surest way to tighten it up would be an EGW "U" die which (under)sizes a bit smaller...

But that shouldn't prove necessary. If you can't push your bullets back into the cases as suggested above, load some and test fire.

Edited November 11, 2016 by MemphisMechanic

[12glocks]

Another option is the Lee Factory Crimp die which uses a circumferential squeezing force on the bullet for crimp.  I would probably not use that with a plated bullet.  Just putting this out there for information purposes.

[lesm]

The EGW   U-die is your friend.  Sizes the case down so you have  lots of tension and you won't have to worry about setback.   Although made by LEE for EGW,   the EGW  U-die is slightly different than the LEE U-die sold elsewhere. I have both and the carbide extends completely to the bottom of the die body on the EGW. On the LEE U-die the carbide is close to the bottom but inset a little. The EGW will size closer to the bottom of the case. The newer versions of both have a much longer threaded section than the old style.  They have plenty of threads for the die holder on my Dillon 550.