A new way to fail to feed

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A new way to fail to feed

Post by kwixdraw on 9/10/2015, 10:30 pm

Testing some loads today and found a strange FTF on a couple rounds. Load is a 185gr RCBS copy of the Lyman 460 SWC with two lube grooves. New Starline brass with 4.5 gr of Titegroup. The bullet is seated to mid driving band and crimped .469.  Shoots pretty well but I had a couple jams in a way I haven't seen before. The empty brass ejected normally but the live round jammed with the rim tipped up at the rear as though it had slipped past the extractor. The nose of the round seemed to be aligned with the chamber and dropping the magazine and retracting the slide about an 1/8 inch and pushing the rim down allows the round to chamber smoothly. The gun is an old GI Remington that I cobbled together for a wad gun. Im thinking that it needs a new extractor with a little more of the bottom corner left on it as the one in it looks pretty rounded down there. I'm thinking that the round being fed is not getting captured as it starts to feed up the breechface and pops loose ahead of the extractor and gets caught while being pushed back down.  Any thoughts or suggestions?
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Re: A new way to fail to feed

Post by Rob Kovach on 9/10/2015, 11:32 pm

Maybe OAL is too long.  Can you show us a picture of your finished rounds as well as the bullet by itself?  In .45, all lube rings should be seated into the case.  Only a skosh of the skirt should be above the case mouth.
If you look at the recent thread about recoil springs, there are links there about tuning the extractor, and it's very common to relieve the bottom corner of the extractor.  I really don't think the extractor is your problem at this point--I believe your magazine isn't releasing the round correctly because of an OAL problem.
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Re: A new way to fail to feed

Post by kwixdraw on 9/11/2015, 6:44 am

If anything I would say the OAL is too short. I'm not smart enough to defeat this Win 8 laptop and post photos but the bullet is the RCBS 185 gr version of the Lyman 200gr SWC with two lube grooves. The driving bands are very narrow so putting the mouth of the case at the mid point of the top driving band gives maybe .030 exposed. These typically feed very well but I was having some fail to clear the ejection port (hitting the bottom of the ultradot and dropping back in) and then short stroking with a 10 lb Wolff spring and loads with 4.2 of TG behind this bullet. The 10 lb spring measures out 10.5 lbs on the spring gauge. With these loads I went up to 4.5gr TG to give a little more positive cycle to the slide and had a couple of the feeding issues described. Recent changes to the gun have been to lower and flare the ejection port and install a long ejector to help clear the empty brass. The ejection pattern seems to be much more consistant now. Magazines are relatively new Metalforms and have given no trouble that I can attribute to them. with the lighter loads everything seemed to go just fine unless the brass hit the Ultradot and got kicked back into the port. Those pieces of brass were typically turned 180 degrees and caught with the mouth of the case against the breechface with a live round trying to feed under it but still held by the magazine lips. Just another bit of info. It appears that the breechface has been repaired with a bushing at the firing pin hole. The bushing seems to be hardened and resists efforts to smooth and polish it.
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Re: A new way to fail to feed

Post by BE Mike on 9/11/2015, 9:53 am

I've shot this bullet in pistol that feed it, as well as, other typical 200 gr. and 185 gr. long nose bullets. I'm no pistolsmith, but although your magazines are a top brand and relatively new, the first thing I'd suspect is that the magazine feed lips need adjusting. I'll be waiting to hear an authoritative response from one of the pistolsmiths.
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Re: A new way to fail to feed

Post by DavidR on 9/11/2015, 10:11 am

the oal, could be fine for other guns just not this one its all in how the chamber was cut, try dropping a round in the barrel and see if it drops flush or a little lower than the hood, if not shorten oal and try again
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Re: A new way to fail to feed

Post by kwixdraw on 9/11/2015, 10:35 am

Plunk tests fine. There has been no change in the OAL of this round and it generally feeds fine. I have a hard time believing that .02gr increase in the powder charge results in this strange behavior. Just a little more slide velocity I'm going to shoot it some more today after a good cleaning and see if it might be related to some crud around the extractor. I think I will check the extractor tension too just to see if it has changed any
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Re: A new way to fail to feed

Post by kwixdraw on 9/11/2015, 11:36 am

Just happened to think. I was using just one of the three Metalform mags I bought. I will do some testing with the other two just to see if the problem can be isolated to the one magazine. They do appear identical and none have any burrs or visible defects to the lips. I polished all of the rounded stainless followers some time back just because it seemed like a good thing to do.
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Re: A new way to fail to feed

Post by Rob Kovach on 9/11/2015, 8:49 pm

Can you show us a picture of the rounds and another of an unloaded bullet?
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Re: A new way to fail to feed

Post by kwixdraw on 9/11/2015, 10:06 pm

Well I think I know how to follow the instructions but I cant get the *(#&5$# photo to download upload cut & paste or anything I want it to so urinate on it....
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Re: A new way to fail to feed

Post by kwixdraw on 9/11/2015, 10:25 pm

There you go. check the avatar.
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Re: A new way to fail to feed

Post by Keyholed on 9/12/2015, 2:37 am

Easy image posting for forums that don't make direct uploads easy. This one is not bad--the forum is built to let you host the image without going to a 3rd party site, which is nice. But frankly, it's almost easier to just post images via Imgur.

www.imgur.com
Free, fast, reliable, and doesn't require you to register. On the downside, if you don't register, you can't delete any images you post, so be mindful of what you're posting. Especially if you're posting on Facebook, or on a forum where you use your real identity. Be as cautions with your stuff on the internet as you would be in real life.

How To Do:

Navigate to Imgur, click on "Upload Images" at the top.
Spoiler:




On the dialog that pops up, select Browse Computer. You can also directly copy pictures using drag-and-drop or Ctrl+C/Ctrl+V from your clipboard, but Browse computer is the easiest, most user-friendly way if you have no idea what I just said. And I still do it that way 99% of the time.
Spoiler:


Find the pictures you want to upload on your computer, click them to select, and then hit "Open". You can also hold down your Control key to select multiple pictures at once, or Shift to select a range of pictures.

Spoiler:


Click Start Upload. You can also click on the X to the right of each image to cancel images individually.
Spoiler:


The red box on the right shows you where to find the link you want. Click on it to highlight, and press Ctrl+C. That copies the highlighted text to your clipboard. If you uploaded multiple pictures, you'll see what I've highlighted in the green box, which allows you to flip between the images you just uploaded, displaying both the image and the links related to it.

Spoiler:


On Bullseye-L, find the second photograph icon from the left. Click on it to open the Insert Image dialog.
Spoiler:




Click in the "URL" text box. Press Ctrl+V to paste the text you copied from Imgur into the dialog box. You should see something like: http://i.imgur.com/######.png, or http://i.imgur.com/#####.jpeg. You can use the optional width and height boxes to automatically resize the image, but it's okay to leave them alone. If your pictures are huge (like mine), you can exercise some forum manners and hide them with spoiler tags (see below).

Click the Insert box when you're done.
Spoiler:

Done!

Spoiler Tag Protip:
On a lot of forums, it's considered really polite to use spoiler tags when you're posting lots of pictures, or very large pictures. For starters, it makes the thread more readable and easier to scroll through.

For another, lots of people still use dial-up connections, either because they don't use the internet enough to justify paying for broadband, or because dial-up is all that's available. Still others might be browsing the forum from a mobile device with a cell phone connection, which gives you  set amount of data every month and then charges you big bucks for overages.

By using spoiler tags, you can hide your images until people decide they want to look at them. Simply type "[.spoiler]" before the image, and "[/.spoiler]" after (omit the quotation marks and periods). With the images hidden, readers won't even have to download the images until they open up the spoiler tags. It even makes the page load faster.

Example:

Code:
[spoiler]YOUR IMAGE HERE[/spoiler]

--

You can also get away with not using the image button on the posting window, by using IMG tags:

Code:
[spoiler][img]http://i.imgur.com/ZzXlWX0.png[/img][/spoiler]

--

I posted this publicly instead of PMing the OP because I thought it might be useful. If it's appreciated, cool. If a mod wants me to put this into a thread someplace to get sticky'd, I'd be most honored to contribute something useful to Bullseye-L. If I've just shamed myself and my family with my off-topic post, whoops, sorry.

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Re: A new way to fail to feed

Post by kwixdraw on 9/12/2015, 8:00 am

It works for me. Thanks. I wasn't expecting email and log in stuff from the forum image host app.
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Re: A new way to fail to feed

Post by Rob Kovach on 9/12/2015, 9:10 am

There are shorter instructions in the sticky instructions in the commercial row forum.
http://www.bullseyeforum.net/t49-instructions-for-hosting-pictures-guidelines-for-posting-items-for-sale


Those rounds look fine.

Here are some other questions:
Does it misfeed with ball?
When it misfits does the magazine have 5 or less rounds in it?
Does it misfeed when you drop the slide off of the slide stop?
How far does your brass go when you shoot these compared to ball ammo brass?
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Re: A new way to fail to feed

Post by kwixdraw on 9/12/2015, 11:00 am

I've never shot it with ball since it has the light spring in it.  This particular misfeed has only occurred twice in about 50 rounds, which is what I had to conduct this test of the load. The problem occurred in mid magazine of 5 rounds both times. So far it has not happened on the first round. These rounds are very slightly hotter than those I have been shooting (4.5 gr of Titegroup vs. 4.3gr) and toss the brass directly to the side and between about four to six feet away. Brass was landing on sand so no bouncing further away after hitting the ground. 
I made up some dummies and hand cycled them through the mags while watching the action of the round leaving the magazine. On the very first one, with only one round in the magazine, the rail began to push the cartridge forward and the nose entered the chamber. The rim reached a point where the curve of the rim was approaching the extractor. I slipped and the slide jumped forward a tiny bit but it appeared that the release point of the magazine is right at the area where the rim should slide behind the extractor hook. I don't know if there was a slight bit of retraction involved in the slip but I managed to end up with the rim on the front side of the extractor hook. I released the slide at that point and it closed normally with the hook snapping over the rim of the case. The round extracted normally. I ran a few more through the slow feeding process and could not duplicate what I just described. The extractor and firing pin stop are standard GI parts and tolerances. I wonder if this could be an example of the extractor rotating under a slight bit of pressure and causing the rim of the cartridge to be unstable just as it is being released to slide behind the hook? The main thing in the actual misfeed, during live fire, was that the base of the case appeared to have been pushed up further than normal and the jammed round appeared to have a slight nose down attitude. I didn't look closely enough at it while clearing it to see what was holding the base up. It seem to me that the only thing that could do that would be the extractor. Possibly the hook was unable to snap over the rim and forced the base up against the barrel hood?  Like you said in the recoil spring thread, Ron, reliability is the key. Alibis are just too costly in a match.


Last edited by kwixdraw on 9/12/2015, 11:02 am; edited 1 time in total (Reason for editing : Grammar)
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Re: A new way to fail to feed

Post by Olde Pilot on 9/12/2015, 11:12 am

Note that the extractor should never snap over the rim of the case. Round should slide up the face of the slide with the rim going under the extractor.

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Re: A new way to fail to feed

Post by kwixdraw on 9/12/2015, 11:17 am

Exactly. That's part of why I'm thinking the extractor is past it's prime. It is polished and has been fiddled with over the years so it just may be that it's had enough.
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Re: A new way to fail to feed

Post by kwixdraw on 9/12/2015, 11:19 am

[img][/img]One last try
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Re: A new way to fail to feed

Post by Rob Kovach on 9/12/2015, 2:04 pm

I'm still leaning towards a late release from the magazine.
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Re: A new way to fail to feed

Post by kwixdraw on 9/12/2015, 9:01 pm

I sure wont say you are wrong Rob. I installed a new EGW extractor and it seems to feed just fine under manual activation. I didn't get to shoot the gun to see what it would do. I set it up with light case rim tension and based on Jerry's photos and descriptions of his set up along with some of the info in Kuhnhausen's books. So no jamming of the extractor into the front edge of the case's extractor groove. I will just have to wait to see how it functions with live rounds tomorrow. So far so good. I hope this is the better solution to the problem than trying to reshape magazine lips.
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Re: A new way to fail to feed

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