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9 major bullet set back


B_RAD

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How much if any is acceptable?

 

I had a dummy round that I pushed against my bench and it moved a lot. Like 0.070".

 

I tried loaded rounds and they were moving 0.008" - 0.010". 

 

I'm thinking this could be causing my failures to chamber issues. 

 

Thoughts?

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Never try to use crimp to solve setback, because it won't. You need to size the case tighter for more neck tension, or get different bullets that are the correct diameter. Consider using a U die. It will solve the problem, if the bullets are actually .355-.556.

 

Eta; any setback is not acceptable...

Edited by RiggerJJ
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Check the diameter of the expander ball, compared to your bullet diameter, and also look at your neck wall thickness.  While the sizer may be adequate, unless the case walls are thin, the expander ball may defeat the sizer.  Typically the expander should be a couple of thousands smaller than the bullet diameter.  I that is not sufficient to retain the bullet, reducing the diameter should given a better grip by the case (assuming you do not have thin walls that are not getting sized adequately).

 

Repeated chambering will move bullets regardless.

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RiggerJJ is correct; use an undersize resizing die.  You can get them from Lee or EGW.  I tried several Dillon dies and could not get one that did not prevent setback.  I got a Lee undersize die and have not had any problems since.

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6 minutes ago, hamiltonian said:

RiggerJJ is correct; use an undersize resizing die.  You can get them from Lee or EGW.  I tried several Dillon dies and could not get one that did not prevent setback.  I got a Lee undersize die and have not had any problems since.

This did happen on ammo loaded with a Dillion sizing die. 

 

Though, I did load up some dummy rounds with my Lee u die and I chbered them in my open gun and they set back a little. Like 0.003". 

 

From what I understand, that's normal?

 

 

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21 hours ago, RiggerJJ said:

Never try to use crimp to solve setback, because it won't. You need to size the case tighter for more neck tension, or get different bullets that are the correct diameter. Consider using a U die. It will solve the problem, if the bullets are actually .355-.556.

 

Eta; any setback is not acceptable...

I'm using a u die now and I'm still getting some set back.  It's a lot less but I'm getting about .003" 

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Personally, I throw out any cases that, after sizing and expanding to 0.353", won't hold the bullet tight. Not worth all the effort. Many of you might just find that with lead or plated bullets, you are actually swaging the bullet diameter down. I get about 1-2 out of 500 or so that I toss.

0.003" set back is not enough to worry about. 0.250", like what started this whole issue, is a disaster. Run some factory and see what set back you get.

Edited by noylj
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That bring up another issue. A crimp die set too hard can do what Noylj is taking about, as in swaging the bullet down. A Lee factory crimp die is notorious for that. Best to use just a slight taper crimp. If you are using one, check by measuring a bullet, seating and crimping it, then pull it and measure again.

Edited by RiggerJJ
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22 hours ago, B_RAD said:

 a dummy round  I pushed against my bench moved 0.070".

 

What powder/bullet are you using ?

 

Lot of 9mm Major powders won't allow bullet set back, because the case

is so full of powder.

 

Matter of fact, a larger problem with many 9mm Major loads is that

the OAL expands (increases) after reloading - may go from 1.165"

to 1.175", and that can cause malfunctions, depending on your

chamber.

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1 minute ago, RiggerJJ said:

Bottom line is, any setback, even 3 thou, is an indication of something not right. You should not be able to push the bullet in by hand, or one chambering should not set it back either.

I'm lost. I'm using a U die. It's adjusted all the way down to touch the shell plate when the handle is down. 

 

St 3 is expanding to about .351".

 

Flaring case mouth very little.

 

Removing flare/crimmping to .377"

 

Bullets are .355"

 

Am I missing anything?

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Doesn't sound like you are missing anything. Could be the brass.

 

I use Dillon dies, 9mm...for minor in Production...there is no way you can push my bullets into the case deeper by hand. Are you absolutely sure you have 9mm dies and not 38super dies?

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21 minutes ago, GrumpyOne said:

Doesn't sound like you are missing anything. Could be the brass.

 

I use Dillon dies, 9mm...for minor in Production...there is no way you can push my bullets into the case deeper by hand. Are you absolutely sure you have 9mm dies and not 38super dies?

Yes. I've never loaded .38. Never had does for it. Only 9. 

 

From memory, I don't believe I've had this issue before. But I'm fairly new to 9 major.  I'm using bought, once fired brass. I'm using Hornady one shot for lube. Spray it in a bag and roll cases around. 

 

The only thing I can think of is the longer OAL isn't providing enough bullet depth to create enough surface area for friction agasint the case wall? 

Edited by B_RAD
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Okay.  I just tried all the tests you yahoos suggested and I get no setback at all.  I can literally push the bullet against the table as hard as I can and it doesn't move.  I can tap it with a hammer and it doesn't move.  It doesn't move when I cycle it through the gun and then measure.  WTF.  I simply run the already processed mixed HS brass through my Hornady dies and crimp with my Lee FC crimp die and all is golden.  Same with 40sw.  No issues.

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9 hours ago, superdude said:

B_RAD4, we need more details. What bullets are you using?

 

And what brass and powder? 

 

 

I'm using mixed brass. 

 

I'm using .355 bullets. 115gr and 124 gr.

 

Powder does not matter.  You shouldn't rely on powder to prevent set back. However, I'm using WAC and AA7. 

 

 

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Hello: You need more crimp. Pull a bullet and see how much crimp you have now. I measure a loaded round 1/8" from the top and write that down. I then measure right at the rim to see if I am getting the 0.003-0.005" crimp. You don't want any setback at all. I hear it all the time on PCC's using factory ammo, bang, bang, bang and then a BOOM. Thanks, Eric

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2 hours ago, Aircooled6racer said:

Hello: You need more crimp. Pull a bullet and see how much crimp you have now. I measure a loaded round 1/8" from the top and write that down. I then measure right at the rim to see if I am getting the 0.003-0.005" crimp. You don't want any setback at all. I hear it all the time on PCC's using factory ammo, bang, bang, bang and then a BOOM. Thanks, Eric

It's my understanding that crimp does not hold the bullet. 

 

I'm removing any flaring of the case and when I measure, I'm at .377".  

 

 

Edited by B_RAD
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Just now, B_RAD said:

It's my understanding that crimp does not hold the bullet. 

 

I'm removing any flaring of the case and when I measure, I'm at .377".  

 

 

This is generally correct. Some tiny bit of crimp may or may not help. The only KNOWN no no is to crimp a whole bunch in an effort to prevent setback. A ton of crimp will actually lessen neck tension

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6 minutes ago, Sarge said:

This is generally correct. Some tiny bit of crimp may or may not help. The only KNOWN no no is to crimp a whole bunch in an effort to prevent setback. A ton of crimp will actually lessen neck tension

That's what I've heard. 

 

 

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3 hours ago, B_RAD said:

 

 

I'm using mixed brass. 

 

I'm using .355 bullets. 115gr and 124 gr.

 

Powder does not matter.  You shouldn't rely on powder to prevent set back. However, I'm using WAC and AA7. 

 

 

 

What specific .355 bullet?  Name brand, plated, jacketed, ????

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