Author Topic: SWC 200 gr seems to crash into feed ramp  (Read 939 times)

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Offline ZenShooter

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SWC 200 gr seems to crash into feed ramp
« on: June 11, 2018, 04:50:46 AM »
Hi,

recently (of course) during a competition a cartridge produced a strange jam. The bullet seemed to crash into the bottom edge of the feed ramp.




It was the last cartridge in the magazine. Magazines are original CZ. OAL was 1.240" or 31,5mm.

Any ideas what could have caused this problem?

Regards and TIA

Offline SI VIS PACEM PARRABELLUM

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #1 on: June 11, 2018, 07:20:17 AM »
How old is the gun? How old is the mag? There have been some recent threads on this. The oal or amount of bullet shoulder
specifically sticking out of the case tends to be an issue with these style bullets.
Could just simply be a mag spring going weak or just an issue with that particular round of ammo and also if it only happened ONE time you don't have any evidence that there's any issue at hand yet. If it becomes prevalent that's another situation.
If anything I think I'd maybe install some new mag springs and see how the gun performs from there.
« Last Edit: June 11, 2018, 07:25:07 AM by SI VIS PACEM PARRABELLUM »

Offline ZenShooter

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #2 on: June 11, 2018, 09:34:07 AM »
Hi and thank you for your input.

How old is the gun? How old is the mag?
Both Gun and Mags were bought from a collector completely unused. I may have run about 1 to 2 K rounds through this gun.

I did have lots of other feeding issues with the the gun which were systematically eliminated mostly by polishing. But this one is new and unique, als the bullet hit the bottom end of the feeding ramp. When looking into the gun from above one can see that the tip of the top cartridge in the magazine is located approximately 1/4" above the bottom end of the feeding ramp. To hit it the cartridge must make an extreme nosedive when being hit from the back during the feeding cycle.

It seems this will not happen as long as a cartridge sits on top of other cartridges because of the inertia of the other bullets combined with the very low amount of friction between those polished brass surfaces. On the other hand the plastic follower offers more resistance to cartridge forward movement while being very light compared to the lead bullets. A stiffer spring might help pushing up but the follower itself still easily tilts forward quite a lot under pressure. So one might also need mags with more tightly fit followers.

Another Question: How often would you clean the mags inside?

Offline Earl Keese

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #3 on: June 11, 2018, 09:51:29 AM »
He asked how old is the gun because there were changes made to the feed ramp depending on year of manufacture.

Offline ZenShooter

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #4 on: June 11, 2018, 09:56:27 AM »
The gun is a CZ 97B and is already equipped with the longer feeding ramp.

Meanwhile I found out how to determine the year of manufacture. On my gun the two digit number near the serial# reads "17". So the gun seems to be quite new.
« Last Edit: June 11, 2018, 10:02:55 AM by ZenShooter »

Offline SI VIS PACEM PARRABELLUM

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #5 on: June 11, 2018, 02:14:26 PM »
I wipe mags out after each use just as I clean the gun after each use. If your gun is a 2017 model you should not be experiencing any feed issues. My 97BD has been flawless from day one with over 5 k through it now. If you are using primarily that SWC ammo then yea it's a work in progress to make a bullet designed for revolvers function well in semi autos. I quit wasting time with those years ago as each different .45 I have wanted a different length setting. My cast 225 gr rn's are just as accurate and feed in anything.
At any rate I'd clean everything up real good and see how she behaves. Like I said above until this one failure becomes more than one it's hard to really condemn anything yet.

Offline ZenShooter

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #6 on: June 11, 2018, 08:17:00 PM »
I wipe mags out after each use just as I clean the gun after each use.
This is interesting and somewhat in contrast to my experiences and habits with 1911 where I disassemble and clean the gun about every 400-700 rounds (about weekly). But all gliding parts are always kept well lubricated with gun oil that dissolves and neutralizes powder residue. A bore snake ist used immediately after each shooting session.

The all metal 1911 magazines are nickel plated and are wiped occasionally on the outside. Dirt does not seem to stick to the nickel plating. They were never opened or cleaned on the inside for about 10,000 rounds each but still work perfectly.

But I understand that the CZ 97 is a different system and requires different maintenance and cleaning. A learning curve applies. Mags will be cleansed regularly.


If your gun is a 2017 model you should not be experiencing any feed issues. My 97BD has been flawless from day one with over 5 k through it now.
Mine was the opposite with about 10% to 40% of jamming cartridges. I had to polish the feed ramp, the slide area opposite to the extractor and the extractor hook itself. Now that the extractor hooks are polished the former OAL sensitivity seems to be gone. This may be the most important step.


If you are using primarily that SWC ammo then yea it's a work in progress to make a bullet designed for revolvers function well in semi autos. I quit wasting time with those years ago as each different .45 I have wanted a different length setting. My cast 225 gr rn's are just as accurate and feed in anything.
My other gun is a LesBaer 1911 and it will eat almost all kind of ammo without problems. So I aim to develop a perfect cartridge for the CZ97 and hope for the 1911 to eat it too.

Offline Earl Keese

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #7 on: June 11, 2018, 08:24:59 PM »
I haven't cleaned the inside of my mags since I've had my 97, probably 700rds. I keep the gun clean, but I'm not obsessive about it. JoeL, a member here shoots his in Bullseye competition and doesn't clean his guns often at all, it's a bit of a running joke for him. FWIW, I load my 200gr coated swc's over Vhit N310 which in my experience leaves the gun relatively clean.

Offline ZenShooter

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #8 on: June 12, 2018, 04:40:44 AM »
JoeL, a member here shoots his in Bullseye competition and doesn't clean his guns often at all, it's a bit of a running joke for him.
Well there are so many different opinions about cleaning. For a long time I just did what JoeL still does even including the jokes. Today I prepare for matches by cleaning and slightly oiling the 1911 and shooting one last training session of about 50 - 150 shots before the match. So I know the relatively clean gun is working flawlessly and during the match there is neither excess oil spraying around nor sticky gun grease overly slowing the slide movement. This way the gun is in a repeatable condition with just enough lube and almost no dirt.

Again the CZ 97 is different from a 1911 and may require a somewhat different maintenance routine which I need to develop. I am new to CZ and therefore I am thankful for all your input. Keeping an eye on the inside of the mags seems reasonable. I found some dirt inside and cleaned it out. Lets see...

FWIW, I load my 200gr coated swc's over Vhit N310 which in my experience leaves the gun relatively clean.
I use 4.2gr N310 just like almost everybody around here for all kinds, shapes and makes of 200 gr coated lead bullets. Of course this is not a reloading recipe for you but only an academic remark. This load seems to be THE sweet spot for 45 ACP with clean burning, relatively moderate recoil and even moderate cost due to the tiny amount of powder.
« Last Edit: June 12, 2018, 06:34:59 AM by ZenShooter »

Offline M1A4ME

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #9 on: June 12, 2018, 06:49:58 AM »
Looks like the angle on those rounds is "wrong" for feeding out of the magazine up the ramp and into the chamber.  If the round isn't "pointed" the at the right angle when the slide contacts it then it probably won't go where it's supposed to go.

A quick/easy check - load the magazine up.  Hold it in your hand.  Use your thumb to push the rounds out of the magazine one at a time.  Look at the angle of each round as it sits at the top of the magazine/feed lips and as you push it out of the magazine.  When you get to the last round is the angle different?  It shouldn't be different.

Have you had the magazines apart?  Sometimes (done it myself) you can get the spring inserted backwards and you get more force on the rear of the follower than on the front.  Not good.  You want the nose of the bullet forced upwards so the bullet angle is controlled by the magazine feed lips.
Better to have it and not need it, than to need it and not have it.  So, if you see me walking the dogs with my SIG 556R, its okay.

Offline ZenShooter

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #10 on: June 12, 2018, 07:52:45 AM »
A quick/easy check - load the magazine up.  Hold it in your hand.  Use your thumb to push the rounds out of the magazine one at a time.  Look at the angle of each round as it sits at the top of the magazine/feed lips and as you push it out of the magazine.  When you get to the last round is the angle different?  It shouldn't be different.
Now comes the crazy unexpected part:

I loaded 10 rounds and removed them one after the other and found that rounds 10 to 7 contacted the round below in the mag only at the base of the case. From round 6 to round 2 they had contact over the whole length. Round 1 was pushed up by the follower just as one would expect. The situation with rounds 10 to 7 remained regardless of shaking the mag violently. So this might be the situation inside the gun when recoil shakes the mag.

But when test shooting yesterday with 10 rounds everything went fine although according to theory rounds 10 to 7 should have caused problems.

10:


9:


8:


7:


6:


5:


4:


3:


2:


1:



Have you had the magazines apart?  Sometimes (done it myself) you can get the spring inserted backwards and you get more force on the rear of the follower than on the front.  Not good.  You want the nose of the bullet forced upwards so the bullet angle is controlled by the magazine feed lips.
The mag has been reassembled. The spring was not taken off the follower so the backwards spring problem should not apply.
« Last Edit: June 12, 2018, 07:54:57 AM by ZenShooter, Reason: Reformatted the image list for better overview »

Offline M1A4ME

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #11 on: June 12, 2018, 08:39:35 AM »
I don't have a 97.  But on my CZ/Mecgar 9MM magazines the 2nd round contacts the top round  - no difference in angles, until I get about half way through the magazine.  Then there is small gap for a few rounds (4 or 5) then as I work towards the last round the top and next round make solid contact again.

The last round is solidly against the feed lips and the follower.  Tight.  If you push on the nose of the bullet down then the follower moves down.

Maybe the 97 magazines are different.  It looks like a gap at the front of the round, between the round and the follower (may just be the camera angle or me not understanding what I think I see.)  If there is a gap (not good contact with the follower then the nose of the round could be forced downward as the slide moves it out of the magazine towards the feed ramp.
Better to have it and not need it, than to need it and not have it.  So, if you see me walking the dogs with my SIG 556R, its okay.

Offline ZenShooter

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #12 on: June 12, 2018, 09:43:13 AM »
Maybe the 97 magazines are different.  It looks like a gap at the front of the round, between the round and the follower (may just be the camera angle or me not understanding what I think I see.)

The CZ 97 Follower has a ramp and looks like this:

« Last Edit: June 12, 2018, 03:12:24 PM by ZenShooter »

Offline ZenShooter

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #13 on: June 12, 2018, 03:27:22 PM »
And here is the explanation why there has to be the ramp:



The flat area in the bottom right hand corner is where the slide stop is engaged by the follower and pushed upwards. So the ridge coming from the back just has has to end somewhere to get out of the way of the slide stop. And they decided to have the ramp (bright area with the light reflecions) instead of a longer ridge ending in an unstable point. This way the follower can be made of reinforced plastic without breaking but will not support the last cartridge all the way forward. The area where the cartridge sits on the follower is marked by the yellow brass residue on the follower.

With most ammo there will never be a problem. Certainly not with round nose bullets. But with the right SWC bullet set to the appropriate OAL probably fed out of a magazine with a dirty follower producing a lot of friction and if the stars align one can stamp a smiley face onto the bullet.

Ist this a friendly gun or what?

Offline SI VIS PACEM PARRABELLUM

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Re: SWC 200 gr seems to crash into feed ramp
« Reply #14 on: June 13, 2018, 10:40:00 AM »
I've had many 1911's over the years and the one thing they had in common was a desire to have SWC bullets seated at different depths for each one. Same with my 97. That's just the way it is when you're using bullets that were never intended for use in autos.
My 97 will shoot any RN bullet and ANYTHING in the modern hollow point defensive lines so there's just no point in fighting to make the SWC work when there are far better more reliable options.