Modified Svi

[Skywalker]

Here is the deal.

A teammate of mine has recently acquired a (not-so-much)used SVI for Modified division, that has this strange habit of stovepiping after the last round has been shot.

Following BE's advice, I fired several rounds without the mag inserted to check if the lack of any push up from mag/rounds could influence the extraction; much to my surprise, the ejection always went on through the mag funnel, and not through the ejection port.

Looks like the spent brass is not being held close to the breechface by the extractor and (when not pushed up by remaining rounds) can easily slip down. By comparison, my Standard Division factory SVI Competition normally ejects through the ejection port when tested by the same method.

I thought "easy, let's have more extractor tension". I progressively bent the extractor to the point that I could hardly manually slide a round under the extractor (with the slide assembly separated from receiver), but the ejection, checked with the a.m. method, always ended in the same way.

The gun set-up:

170 grs. JTC bullet @ 180 PF

factory recoil spring

shock-buff

new SVI mag springs and followers

At present I'm considering to check the (detachable) breechface dimensions, to see if there is a chance it is too "slim", resulting in an abnormal gap between extractor and breechface. I have also tried different extractors (both STI, SVI and even Colt .45) but nothing cured this malfunction.

I'm ready to listen to all your suggestions.

[mpolans]

Do you have the right ejector installed?

[Skywalker]

Yes sir,

factory one with front right corner broken as Ed Brown teaches in his 1911 bench reference guide.

[L9X25]

This may sound strange but try bending the extractor downward so that it is closer to the bottom of the extractor tunnel. You should also remove some metal from the extractor to allow it to move closer to the firing pin hole. There is a "pad" beside the hook which allows this.

The problem is that, despite the tension, the fired case is not being held by the extractor once the barrel unlocks and slides it downward.

You can add all of the extractor tension in the world but, once the extractor contacts the breechface, it will not maintain tension on the case.

Good luck,

Leo

[Julien Boit]

Hey Skywalker,

I'm pretty Ok with what Leo said about the Extractor, i just want to add something.

Check the extractor claw, it must be perfectly parrallel with the breech face if not, sometimes the extractor would play the role of the ejector before the ejector

I know it sounds weird but if the claw as a little angle, it can cause the brass to be extracted from the chamber then immediately after the brass want to eject before it reached the ejector and could fall if not supported by the mag or a cartridge.

Another thing I did, after I talked with a very reputable gunsmith, is to fit the extractor to touch the case between the rim and the bevel of the case (sorry I can't find the word ).

He (the gunsmith) once realized that this is where the cases are the most consistent in shape and dimensions.

Since, I've never experienced again that "one on xxx rounds un-understandable stove pipe".

[Skywalker]

Julien, Leo, thanks for advice.

After reading your posts I went back to my "school books" from Ed Brown and Bill Wilson, and discovered the way to let the extractor get closer to the firing pin hole (I was erroneously thinking that bending the extractor was supposed to do this).

I have also noticed that there is a great post in these forums linking to detailed explainations from Bill Wilson: damn, I knew that going back to the basics usually helps, but was too conceited to go back to beginners base knowledge .

Next time on the range I'll try to re-shape the locator pad to get the extractor groove in deeper contact with the brass rim (actually the throath between brass boy and rim), and will also have a close look at groove depth and positioning relative to breechface.

Thanks again.