45 1911 setback issue

JCSC

JCSC

Member
Joined
Jul 24, 2019
Messages
597
Location
Columbia SC
Well I have finished the work in my 1911 and ran it thru the paces tonight. I had several jamb issues and one related to a major setback in a cartridge.

I still need to disassemble and mic components, for investigation, but I would like to know what would have happened had it chambered correctly. Would it cause a significant pressure issue?

I did several setback tests with this gun after some initial concerns and it frequently sets back .010” when you chamber one. The choice was made to limit chambering and rechambering the same round.


Need to find out what I did wrong.

IMG_3107.jpeg
 

Taper Crimp: Everything you need to know

Taper Crimp: Everything you need to know
czfirearms.us
This gentleman is one of our members. Looks like you have RCBS dies, so this will apply.

I had trouble with .45 like this once. I tore the die’s down and started back from scratch. Whatever I was doing wrong went away.

Mic your finished case against SAAMI specs and see if something jumps out at you. Generally, a taper crimp should be around 2x case wall thickness plus bullet diameter.

You will probably hear about Lee Factory Crimp dies in this thread. No offense to Lee Precision or those that use them, but I’ve never owned one and have done ok over the years.

I probably should ask if you’ve successfully loaded with these dies before? I’ve never personally seen a faulty die, but one never knows ….
 
JCSC said:
I had several jamb issues and one related to a major setback in a cartridge.

Need to find out what I did wrong
Click to expand...
We need more information to help you.
  1. Are you using mixed range brass?
  2. How much are you expanding the case mouth/neck?
  3. Can you describe the "jamb issues"?
  4. Bullet brand, weight, type (FMJ/plated), size/diameter
  5. Amount of taper crimp
  6. Pistol used
 
JCSC said:
I did several setback tests with this gun after some initial concerns and it frequently sets back .010” when you chamber one. The choice was made to limit chambering and rechambering the same round.
Click to expand...

I've chambered 45acp dummy rounds ten times, measuring before chambering and after each chambering, and my total setback was between .006" and .008". My testing was done by using the slide stop to release the slide.

Like others said, take some measurements and figure out why your ammo is setting back. If you keep shooting it the way it is, you may get another round that sets back like the one in your picture but actually chambers. I wouldn't want to pull the trigger on that round, that's for sure.

chris
 
1911 45 ACP with lots of rounds thru these dies.

200 gr Xtreme RNP with mixed brass.

Jamb was the classic 1911 jamb. Basically stuffed in to the feed ramp and stuck.

I only flare enough to get 1/16” of the bullets to rest in the case. Crimp is .470/.471.

As mentioned, I will take some measurements .I am very cautious, but maybe I had an unsized pc make it thru the process.

Update. S&B brass. Obviously not sized. I have a newly sized S&B in front of me that’s .468 at the mid point sized not loaded.

My set back brass measures .474.

This is upsetting to say the least. I take a lot of pride in the process I follow for my loads. I’m going to do some checks on this rest of this bullet lot and see if I have a bigger issue.
 
Last edited:
can you get a sized (not expanded) case mouth diameter measurement? case wall thickness is .010" so you can find out if your sizing die sizes enough to hold the bullet securely. mouth diameter minus .020" should be a couple thou less than bullet diameter.

luck,

murf
 
JCSC said:
200 gr Xtreme RNP with mixed brass.
Click to expand...

Ah HA!
I had the very same fault with the very same combination; bullet setback leading to feedway jams.
Fortunately I did not have one bounce into the chamber and overpressure the gun. I did all the witch doctor rituals described above and more besides. Then I considered how to really fix the problem.
I got an undersize sizing die, made by Lee although I bought mine from EGW. That sizes the brass down to where there is a visible constriction - "wasp waist" or "coke bottle" - in the loaded round and the neck is tight on the bullet. That keeps the bullet from setting back.
I salvaged the ammo on hand by impressing a cannelure in the case at the base of the bullet, like some factory loads.

Same situation with Xtreme 115 gr 9mm as 200 gr .45, they are both small in diameter, have short bearing surface, and a slick soft surface. I managed it the same way with an undersize carbide die.

Undersize Reloading Dies - Smithing/Tooling

.38 Special & Super .40 S&W/10mm .45 ACP 9mm Luger
www.egwguns.com www.egwguns.com

Note: A 230 gr .45 (or 124-147 gr 9mm) has enough more bearing surface and seats deeper into the taper of the case walls to not need the "U" die. Neither do coated or cast bullets which are usually a thou or two larger diameter and less slick on the surface.
 
Would a case gauge have caught the unsized brass?

I do not own any gauges for pistol, but I’m going to by Monday.
 
Last edited:
Jim Watson said:
Ah HA!
I had the very same fault with the very same combination; bullet setback leading to feedway jams.
Fortunately I did not have one bounce into the chamber and overpressure the gun. I did all the witch doctor rituals described above and more besides. Then I considered how to really fix the problem.
I got an undersize sizing die, made by Lee although I bought mine from EGW. That sizes the brass down to where there is a visible constriction - "wasp waist" or "coke bottle" - in the loaded round and the neck is tight on the bullet. That keeps the bullet from setting back.
I salvaged the ammo on hand by impressing a cannelure in the case at the base of the bullet, like some factory loads.

Same situation with Xtreme 115 gr 9mm as 200 gr .45, they are both small in diameter, have short bearing surface, and a slick soft surface. I managed it the same way with an undersize carbide die.

Undersize Reloading Dies - Smithing/Tooling

.38 Special & Super .40 S&W/10mm .45 ACP 9mm Luger
www.egwguns.com www.egwguns.com

Note: A 230 gr .45 (or 124-147 gr 9mm) has enough more bearing surface and seats deeper into the taper of the case walls to not need the "U" die. Neither do coated or cast bullets which are usually a thou or two larger diameter and less slick on the surface.
Click to expand...
I too use undersized dies for 9mm & 45acp. In addition to the objective differences, I noticed a more consistent firmness to my 9mm bullet seating.
 
CQB45ACP said:
I too use undersized dies for 9mm & 45acp. In addition to the objective differences, I noticed a more consistent firmness to my 9mm bullet seating.
Click to expand...
Does anyone have the expander dimension for the 45 under size set? Mine is currently .448 for the rcbs set and a sized pc of blazer brass is .442” inside diameter before expanding.

I was sizing a few this afternoon and the expander feels like it opens the case up a reasonable amount. I would imagine a U set just has a smaller diameter expander?
 
Last edited:
JCSC said:
Does anyone have the expander dimension for the 45 under size set? Mine is currently .448 for the rcbs set and a sized pc of blazer brass is .442” inside diameter before expanding.

I was sizing a few this afternoon and the expander feels like it opens the case up a reasonable amount. I would imagine a U set just has a smaller diameter expander?
Click to expand...
Good question but beats me.

I’m embarrassed to ask, what’s a U?

Edit: I still use standard expander.
 
Last edited:
JCSC said:
Does anyone have the expander dimension for the 45 under size set? Mine is currently .448 for the rcbs set and a sized pc of blazer brass is .442” inside diameter before expanding.

I was sizing a few this afternoon and the expander feels like it opens the case up a reasonable amount. I would imagine a U set just has a smaller diameter expander?
Click to expand...

I would think the undersize die set is only the sizer die that's undersized. If the expander was undersized the bullet would be too large too fit in the brass.

@CQB45ACP ... Bat signal is sent up, maybe he can take some measurements for you.

chris
 
ballman6711 said:
I would think the undersize die set is only the sizer die that's undersized. If the expander was undersized the bullet would be too large too fit in the brass.

@CQB45ACP ... Bat signal is sent up, maybe he can take some measurements for you.

chris
Click to expand...
Yes true that. Maybe someone will splain the entire mechanics behind an undersized die and it’s affect on brass. I can’t.

Speaking only for me, I only expand a little and never flare and chamfer slightly. As a result I’m telling you I get a snug fit and no crazy looking wasp waist.

Edit: BUT except for a few testers of other headstamps, I’m only using Winchester cases for the time being.
 
Last edited:
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