Setback Problem

Dave, It sounds like you don't have enough tension on the bullet. You need to put a firmer crimp (taper, not roll) on the bullet. Even with a misfeed, a bullet should not be pushed back into the case. A benefit, a firmer crimp usually promotes more complete powder burn.

Look at sizing. http://www.midwayusa.com/product/386755/lee-undersized-carbide-sizing-die-9mm-luger And check the expander for the correct diameter. It can be made smaller if needed. Stop using the Lee Factory Crimp die on lead or plated bullets. Different brands of brass will produce different neck tensions. Bullets will move if you can put 45 or more pounds pressure on them. Measure the neck area before and after seating the bullet. It should expand .002" or more on seating.

There can be multiple causes for the set back to occur. Expander dimensions as noted before are first. You basically want to see the expander be .001-.002 less than the .355 bullet diameter. With bullets of the proper dimension, this will create sufficient neck tension. This would be the same theory used for bottle neck cartridges, that are not typically crimped but simply rely solely on neck tension. For the taper crimp, you can take your caliper and measure the crimp on a factory round. Use this as a base line and adjust as necessary to get what you are looking for. Brass can be very different depending on brand. I often see remington brass have a lot more elasticity (memory). You can feel it going in and out of the dies by the change in resistance. Old brass with a lot loads on them can work harden and have odd characteristics as well. If it were me, I would mic my bullets and expander ball first. Correct anything there. If they are ok, then reset your crimp based on a factory round. I hope this helps.

Place a dummy round on a bath room scale .
With double thumbs , apply pressure. Note reading on scale when the bullet moves. Wear a glove, so your not cut by the brass. How strong are you? With 45 acp, 45 to over 100 lbs , using different brass , wnen appling pressure with leverage and wood piece.

what brand of bullets are you using and what brand of brass are you using ?
How many times has this brass been loaded ?
I had an issue in the past with a bad batch of brass that the case wall was to
thin and allowed set back , I tossed that batch of brass never had an issue
again.
also what dies are you using and are they new meaning can they be defective ?
You for sure need to find the root cause of this set back can be bad thing !
maybe post more info like what bullet,brass,die, ?

The term "expander" is being used, but none of the pistol die sets I have use an expander. Most will have a flaring tool/die (to facilitate bullet seating), but no expander like is used on rifle dies to size neck ID. Measure the bullets. Make sure the case is entering the sizing die all the way. Some cases have pretty thin walls, comparatively, and neck tension isn't quite enough with min. diameter bullets. I can safely say that mu Lee dies in 9mm and 2,000 assorted headstamp cases with commercial jacketed and home cast bullets I've never had a set back problem, and I don't crimp. I just remove any flare with a taper crimp die...

BTW, use the scale method mentioned above, as some feller's thumbs can be very strong...

what make of brass are you using?

murf

Walkalong said:

Neck tension holds the bullet in an auto caliber like the 9MM. No amount of "crimp" can fix poor neck tension. Period. The taper crimp on an auto caliber is too remove the bell or a hair (.001) more. It does nothing to hold the bullet.

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This 101 level knowledge, yet so many preach crimp as a solution to prevent setback, while ignoring the fact the cartridge headspaces off the case mouth!

Either the sizer, the case, or the bullet is out of spec, or the brass has been work hardened.

Possibly all of the above.

sc dave,

the wilson case length gauge only gauges length, not diameter.

you may be putting too much flair on the case mouth with the expander plug. use one of your bullets as a gauge and only expand the case enough to just barely stick the bullet in the case. the 115 grain bullets don't have much full diameter surface area as it is. the more flare you use, the less neck/bullet tension you will have.

also, what is the diameter of your expansion plug?

murf

Bullet pull - Neck tension.

What called my attention to this was when practicing yesterday I had a double feed. I cleared the issue and then when picking up my brass I noticed the setback round on the floor. Now, did the double feed jam cause the setback?

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I am guessing yes. Your neck tension is inline with Federal's ammo, military 5.56 minimum of 35 lbs bullet pull.

BULLET PULL: Minimum individual 35 lbs.

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http://www.mlefiaa.org/files/ERPR/XM193.pdf How i measured, may not be like the GI ammo. I seen another persons test. See photo. [/URL][/IMG] Click for larger view. Measure the neck area before and after seating the bullet. It should expand .002" or more on seating.

I think people sometimes are too eager to blame the Factory Crimp Die. If you know how to use it you can go from just taking the flare out if the case mouth to giving the rounds a full taper crimp. I've been using one on all of my pistol rounds for years and never had a neck tension issue or anything else that can be blamed on it.

I gotta say this again; there is no expanders in any of my pistol dies (I'm not the smartest feller in town, so I just looked to make sure). My 9mm dies, Lee and Lyman have no expander. My 45 ACP dies, Lee and Pacific, have no expander. My .44 Magnum dies, Lee and RCBS, have no expander. My 38/357 Mag. dies, Lee, have no expander. So if I'm wrong let me know. If not what the H$&!! are you talking about? :banghead:

How about starting a sticky on bullet setback issues and fixes. It seems to be a common occurrence judging the number of threads that I have read here and elsewhere. Sadly the recommendation of increasing the crimp is always given. In my experience overly crimping will reduce neck tension and cause more set back. The root cause is that the bullet is too small for the inner diameter of the sized brass. This is caused by a too small of a bullet, oversized expander (or flair die if you with to call it that), brass thickness, oversized sizing die for the brass used (due to brass thickness). Measure your bullets, inside diameter of sized brass, and size of expander. Lee calls theirs the powder through expander die. If you bought new it's part of their three and four die set. If you bought used lee die sets then someone shorted you a die. This die puts a bell on the case mouth, but it also expands the inside of the case. Don't think of it like the rifle sizing dies that has an expander button on the sizing die, as it doesn't work like that for straight wall cases.

mdi, RCBS inside a 3 dies set. 38/357 Dillon powder funnel expander 45 acp. Dont know about "your" dies. SAAMI

EXPANDER PLUG 1. A cylindrical plug of proper diameter that is inserted into the neck of a resized cartridge case to expand the diameter to its proper size. Also called Ball Sizing Plug.2. A tool used to remove dents in shotgun barrels.

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For straightwall or slight taper (9mm):

An earlier RCBS set I have does incorporate an expander in the decapping pin, it is the only set I have that does.

My LEE sizers (380, 9mm, 10mm, 45 Colt) do not.

Lee Pin:


LEE's Powder Through die bells, there is no expander.

SC_Dave said:

Per Walkalongs post.

I sized and bypassed the flare step on 3 different type brass. So I sized and went straight to seat and taper crimp.

Federal took 40lbs to set back
PMC took 38lbs to set back
Speer took 32lbs to set back

This took the expander out of the picture completely.

All of my cartridges go through a Wilson case gauge so that tells me I must be taking all or most of the expansion out right?

Does this only leave the sizing die?

SCD

Click to expand...

You also need to omit the crimp to see if that is causing the problem.

ID - pin gauges are needed. None here.

One other thing you might have for a problem would be 380 sized bullets and trying to use them in 9MM. They are smaller in diameter and would not work in 9MM brass. I see nowhere when re reading the posts that you actually measured your bullets diameter to see if they were what the package said they were.

ETA: RC reminded me that both 380 and 9MM are supposed to use the same size bullet and that is .356.