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Old January 5, 2019, 01:23 AM   #1
chris in va
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Diagnose 45 ACP issue

My CZ 97b broke a barrel lug...again.

It seems a 200gr LSWC works best around 5gr with Bullseye, but I was having ejection issues and upped it to 5.5gr, still under max per the Lyman manual. It would still jam every so often with the empty case flipped around backward.

Is this too hot? Could my recoil spring have been too weak, whacking the slide stop too hard? Maybe the powder creates too fast of a slide speed? Any other recommended powders to prevent this?

Any help would be appreciated, once I get it fixed again I'm not trying to kill it a third time.
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Old January 5, 2019, 04:02 AM   #2
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>"It seems a 200gr LSWC works best around 5gr with Bullseye, but I was having ejection issues and upped it to 5.5gr"

My suggestion is to change to a slower burn rate powder. Back in the days when I used to look for a generic loading for all of the same caliber autos (one load for all 9mm autos, regardless of gun brand as example) the first thing that worked for me was to discard all the really fast burning powders. I still use them but not for reliable semi-auto functioning.

In your case, my best guess as to what is happening is that lets suppose the peak pressure of your 5 gr load was occurring when the bullet is maybe an inch down the barrel after being fired. A fast burning powder tends to have a rather sharp (spike) pressure curve and the drop down can be fast enough to end adequate recoil force. Picture the fast burning powder as more like a rapid hammer blow to the recoil assembly where a slower burning powder will tend to flatten out the peak pressure and begin to resemble a more steady and continuous force on the recoil assembly. When you went to the 5.5 gr charge, while you increased the peak pressure (swung the hammer harder) the pressure curve is still the same spike in almost the same place. I predict the new load will still give failure to extract on occasion but has significantly increased shock wear on the gun.

In the order of decreasing burn rate, here are some suggested powders to try for reliable semi auto function, ergo improving the pressure curve for better recoil performance. Unique, power pistol, and silhouette, the latter being designed for additional gas for auto function. I can give you the generic loads for the above recommended powders for the 45 auto but I do not want to violate any board rules here by doing so.
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Old January 5, 2019, 10:01 AM   #3
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Sounds like a gun problem. 5.0 grains of Bullseye is starting to get hot and if a gun doesn’t function with that charge something is going on with the gun. I can shoot 4.2 grains with a 200 grain SWC in any of my .45’s including a Glock 22, a S&W 4516 along with a number of 1911’s, some with reduced power springs and others with full strength springs.

Bullseye is the perfect power for 45 ACP. Fast to medium speed pistol powders are what you should be using in 45 ACP. It’s thought that Bullseye is probably the most common powder used in 45 ACP for the last 100 years.

I’d be looking at the extractor, ejector, etc. How are going to fix the broken barrel lug?
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Old January 5, 2019, 10:07 AM   #4
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Looking at Alliant's load data, your too hot.
Max load listed is 4.6gr.

Of course i'm over Alliant's max for 200 gr LSWC and Unique.
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Old January 5, 2019, 10:29 AM   #5
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The " again" would bother me . I'm kind of new in 1911's I would think barrel fitting . I haven't any background in gunsmithing but I see with a 1911 or for that matter any auto , timing is important , link adjustment , magazine and recoil springs , extractor and ejector .

I got into 1911 45 ACP when I bought a Colt New Agent it's one of those 3" autos , enjoyed shooting it so much I started reading up on them . I started on the low end of the W231 powder scale using a 230 gr FMJ's ordered recoil springs ,extra magazines , a tool to adjust extractor tension . Not into taking a file to anything yet . Working up a load that functioned 100% is when I stopped increasing my load .

Did you try different magazine & recoil springs when LISTED load for the bullet used didn't work ? Seem like what ever problem you had with the first barrel is still there , the increased powder charge didn't fix . Hope the guys here with more experience can figure it out . Hope things work out .

Chris
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Old January 5, 2019, 12:37 PM   #6
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Looking at reloading manuals Bullseye 200 grain LSWC

Speer #14 start load 4.2 max 4.6
Lyman cast bullet manual
Lyman#4 cast start load 3.5 max 5.6 Lyman mold 452460
Lyman#4 start load 4.9 max 6 Lyman mold 452630
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Old January 5, 2019, 01:53 PM   #7
T. O'Heir
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"...broke a barrel lug...again..." That's not an ammo issue.
"...still under max per the Lyman manual..." Not for a cast bullet. As mentioned, 5.0 of Bullseye is .4 over Max for a 200 grain cast bullet.
5.5 grains is nearly a full grain over max.
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Old January 5, 2019, 03:07 PM   #8
chris in va
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My Lyman #49 lists a 200gr LSWC at 6.0gr max.

I have to send it back to cajun Gun Works for a new barrel and fitment, CZ isn't going to repair it as it's been customized. This time I'll try a stronger mainspring.

Last edited by chris in va; January 5, 2019 at 03:16 PM.
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Old January 5, 2019, 03:27 PM   #9
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From Lyman cast manual # 4 first printing 2010 page 277
Lyman 200 grain cast #452460 200 gr
Bullseye 3.5 gr 645 fps pressure CUP 6900 5.6 gr 869 fps pressure CUP 15700

Lyman 200 grain cast #452630 200 gr
Bullseye 4.9 gr 840 fps pressure CUP 12900 6gr 909 fps pressure CUP17000
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Old January 5, 2019, 06:53 PM   #10
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I wouldn’t worry about the 5.0 grains of Bullseye. The loads that stop short of that are all reduced pressure target loads where they stopped because of leading or accuracy started to drop off. In the manuals that list pressure you can tell 5.0 isn’t going to cause any problems in a CZ 97 which should be able to handle +P loads without issue.

With that said, I doubt a stronger mainspring will do much to fix the problems you’re seeing. If the gun is not throwing the spent cases like it should I’d look at the ejector and extractor first.

Last edited by reddog81; January 5, 2019 at 07:14 PM.
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Old January 6, 2019, 01:30 AM   #11
chris in va
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It's my understanding CZ lengthened the ejector a bit in the more recent version, I'll look into getting one. Extractor and spring were replaced.

It was a weird jam, the spent case was flipped around backward horizontally and nobody I talked with had any inkling why it would do that.
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Old January 6, 2019, 02:21 AM   #12
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I still can't help but think that maybe it's something in your frame that's out of spec and causing those broken lugs.
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Old January 6, 2019, 09:30 PM   #13
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Chris,

The flipped around case usually indicates inadequate slide velocity, but there are scenarios in which excessive slide velocity can cause it, too. The standard old hardball match load assembled by Frankford Arsenal in the 1920s and still good today, was 5.0 grains of Bullseye behind a 230 grain RN FMJ bullet. This would have about the peak pressure of your current load and a longer barrel time into the bargain, driving the slide back harder. So I don't believe you should be overtaxing the gun with your load. The 4.6-grain limit in some load data is most likely to limit leading rather than pressure.

The lug damage is odd, and I suspect a timing problem, like the barrel and slide unlocking slightly early. But without examining the gun, I really can't say. If factory service is not getting you relief, see if you can find someone who does a lot of work on these guns. Comparing two side-by-side might help. I am not immediately spotting any kind of shock buffer or recoil buffer being available for this gun. If it were a 1911, I'd tell you to get one of the square bottom EGW firing pin stops installed.

How does did it function with hardball, assuming you tried that?
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Old January 7, 2019, 12:25 AM   #14
chris in va
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I can't really say, pretty much everything fired has been some form of Lee mold, and the past couple years have been powdercoated. I searched high and low for an affordable LRN mold that duplicates factory hardball with little luck. I settled on the Lee SWC, not thrilled with it but feeds decently enough.

It's possible CZ didn't fit the first new barrel quite right to the slide, or perhaps 5.5gr BE was just too strong for that action. They did say it was unusual for the lower lug to break (again) as the slide stop pin should have broken first.
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Old January 7, 2019, 08:49 AM   #15
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5.5gr of Bullseye is very hot for a 200gr LSWC. I went up to 5.2gr once to experiment, and wash pushing 920fps. Much too fast for what I consider a target bullet. Also I experienced a lot of lead build up in the barrel.

If you want hot loads switch to FMJ and a medium powder like BE-86. It it were me I'd load the 200gr LSWC bullets over 4.2gr of Bullseye and use them for target practice
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Old January 7, 2019, 10:14 AM   #16
chris in va
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I was using powdercoated, so no leading issue.
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Old January 7, 2019, 12:28 PM   #17
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Yes, and because the bullet is lighter, QuickLOAD shows there's not a lot of difference in peak pressure from the classic hardball load of 5 grains of Bullseye. It should be fine, but just usually isn't done with cast bullets because of leading issues, not pressure issues. A few decades of IPSC power factors have got people used to larger quantities of slower powders and they've forgotten the 45 Auto's roots.
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