9mm FNC 9C failure to battery

[Bait O' Eggs]

Hope this is the correct forum, there are so many forums on this page sometimes it is hard to tell where to ask the question.

Having some failure to battery issues with cast bullets. Not sure if the issue is the cast bullet or how I am loading them.

Fairly new to casting bullets (1 year or so) and reloading them. I am using a Lee 9mm 124 grain round nose mold, casting 6 bullets at a time. Powder coating with Harbor Freight red and then sizing them at 0.357. Loading the rounds with 4.6 grains of Winchester 231.

I have 3 each Sig 365's that eat these all day long with no issues. A buddies Glock 43 has no issues. I have a FNS 9C that doesnt like them. About every second or third shell failures to battery. And it isnt a simple work the slide to clear. The slide is jammed hard, and I have to push the front of the slide on something like edge of a stump to get the slide to clear the jammed casing. I am a pretty strong guy and I cant work the slide loose by hand. I have tried to lube the slide and didnt help the issue. I even had it dripping Remlube when trying to get it to cycle.

The FNS 9C has around 400 rounds thru it (fairly new), and it eats factory ammo with no issues. I start comparing the ammo it eats to what it gags on, and I see the factory ammo is 1.110 OAL. My reloads are 1.142 OAL which is still shorter than OAL in the books at 1.16.

I have not tried to shorten the OAL of my reloads yet to see if it feeds better. It seems to me it is one of a few possible issues.
1. Not enough spring to seat the follow up round after firing, maybe adding powder will work the slide more fully giving the spring additional ability to cycle the gun. I assume the slide is fully cycling, the gun always locks back after last round fired. So this probably isnt my problem is a guess???
2. Maybe I need to size bullets to a smaller diameter, though I would think the painted lead diameter isnt keeping the gun from going full battery, it is about 1/8 of an inch from fully engaging the next casing when it failures to battery. I see no markings on the powder coating bullet when it doesnt battery. I know it is 0.001 over book, but can the FNS be that tight to tolerances?? I cannot hit the back of the slide with the heal of my hand and get it to battery.
3. Maybe seating the bullet deeper (increasing my pressure), will allow it to go into battery. I have noticed no marks on the powder coating when a casing failures to battery and I have to essentially pound it out. My OAL is a bit more than the factory ammo that does cycle with no issues so maybe this is it.
4. It is the wifes gun, and she could be limp wristing it, but it does the same thing when I shoot it and I am fairly confident I am not limp wristed

Have I pretty much identified the potential issues? Is there something I may be missing?

What confuses me is when it failures to battery, it is locked up tight and doesnt clear easily, yet I dont see any sign of why on the casings or bullets. I would expect to see powder coat scraping or something???

Open to suggestions to try before I begin the problem solving.

[fredj338]

Generally the OAL is too long. You can put a black Sharpie around the exposed bullet & chamber it. IT only takes 0.002-0.003" extra OAL to get it stuck in a barrel with short/sharp throat. Also check your are not over crimping. This can bulge a case at the mouth & resists going into battery.
If OAL is too long, then shorten them up 0.010" & shoot that in all your 9mm. I would drop my powder charge a bit too. As always, OAL will vary with each bullet & each barrel. For multiple guns I load to the longest OAL that works in all of them. With lead bullets you are over suggested max data.

Manufacturer Winchester
Powder W231
Bullet Diam.
C.O.L. 1.125"
3.9gr 1,009fps 25,700 CUP
4.4gr 1,086fps 31,200 CUP

[Rcmaveric]

Have you measures the seating depth yet? What does the extracted round look like? Any scraping by the throat?

I reload cast for 5 different 9mm with the Lee 125g rn. You need to measure the seating depth off all the guns and the go with shortest COL -.003 inches. I seat to 1.05 inches. Then gently work the crimp till the rounds easily chamber in all of them. Once you have the dummies made you can use it to set up your seating and crimping die for consistency and repeatability.

I had simmilar problem. All me my 9mm would eat my ammo except for my compact and revolver. Seated to 1.12 will not chamber into my compact fine tuned down to 1.05 fixed all that. All chambers and throats are NOT created equal.So i had to start from scratch. It really didnt effect my accuracy in the other guns though. I actually think it solved my random 9mm leading issues i have been having.

Seating out will decreases pressures up to the point until the bullet is seated into the lands. Seating into the lands causes a relatively high start pressure. The pressures has to build enough to pop that bullet into the barrel were as if the bullet has a for thousands head start pressure are lower.

Definitely sounds like seating depth. Going .002 or .003 of the shortest COL should solve your problem.

[Cherokee]

Why don't you use the 1.125" OAL and drop to 4.4 231 to a least hit the book data show above.

[Bait O' Eggs]

Thanks for the thoughts I will try to shorten OAL. It seemed like the easiest adjustment to try first.

I will also back off the powder to 4.4 grains.

[bedbugbilly]

What did your dummy rounds show you with this gun when you hand cycled them/ You did load up dummy rounds to check OAL? No two 9mm chambers are created equal . . . try some dummy rounds and a black sharpie - that will tell you if your OAL needs to be shortened or a little more taper crimp for that particular handgun. Once you get that figured out - then you and your wive both shoot it - if limp writing is an issue, that should tell you . . . or have a third person shoot it.

[crackers]

Diameter. Tula brass is my headache - not that it's bad, just thick. If it were a length issue then the bullet would be sticking out an extra .125 to hold the slide open that far. The 9luger is really a tapered case and binding on the diameter is why you need seven hands to open the slide. The first time I had to deal with that was the last time I considered it a close-up defensive round.

[Bait O' Eggs]

loaded 40 rounds tonight, 4.4 grains and 1.115 OAL, every round went thru the gun perfectly, slide open at the end of each magazine. Seems they were a bit long for this gun. I think I have the issue resolved. Thanks

[reddog81]

It sounds like you got it figured out so hopefully everything is fine. If it happens agin try and figure out if the bullet is sticking or if the brass is sticking. The brass can stick if it's not sized all the way down or if the belling from the expander die isn't removed. If you can't tell where the rounds are sticking you can mark the case with a sharpie and see where the ink gets removed.

[marek313]

Not every 9mm will chamber .357 as many have tight throats. You might need to get that guns throat reamed. That will allow you to chamber .357 seated to any length. Dougguy here can do it for you. He does fine work and he'll even put a crown cut on the barrel if you want to. Had the same problem with my Canik TP9 SFX.

[Tom W.]

The Glocks that I had and the Ruger that I have will gobble anything that I feed ( or fed ) them. My CZ will give me fits if I try to feed it .358 diameter boolits. It will work just fine with .357 sized t/c from my Lee mold.
I have had to press the CZ slide back using the wooden bench a time or two myself. I inspected the round and found a very tiny ring of lead that would stop the slide from going into battery. I could scrape the ring off and it would function just fine. That's when the bulb lit up and I tried the .357 sizer.