Marushin M712 - extractor getting stuck (#M18) problem.

Fine folks,

An M712 (metal) has a problem ejecting cartridges. It didn't properly eject at first shots (carts were left in barrell), then suddenly extractor (part M18, the one that holds cartridge by rim to pull it out of chamber) flew out together with the next cartridge. Cause unknown.

I was able to put it back in place, and while manually cycling discovered that when extractor is raised (cartridge in chamber), it also slides slightly backward, and two "thingies" (oh, I always run out of English names for things) at its sides get slightly up and out of their holes resulting in the whole extracter wedged in that position. This means that when bolt&extractor move backward, cartridge is not grabbed and not ejected. This might be the original problem, or a new one.

Any thoughts?

I'd guess that extractor tab has to be removed and bent somehow to not allow for any movement when it is inserted back in slide.

Hi smootik,

I've experienced similar problems with mine too. The extractor isn't pinned in place is it, those 2 "ears" seem to be the only means of keeping it in place.

I haven't had time to study mine yet so I'll certainly be following this thread with interest... Thanks for bringing it up

Quote :

smootik

Did you solve your problem?

I am not 100% sure yet.
I have bent extractor slightly down. Now it does not block as previously, but don't know if it is permanent.

smootik,

I think I've experienced a similar problem.
When I fired my metal M712, it was ok at the first time, but later, the extracor comes off from bolt head with stucking at a rim of cartridge.

M712 does not have independent spring to move extractor put in right place, therefore, the extractor should have some sprint tention nature on it's metal. But, the one from Marushin is bold-normal-nothing special piece of metal. If you really want to solve, I think you need to make one up from a sheet of steel?

I am also seeking a solution.

shaz,

I think I have found a solution

I was looking at Cerywns Mauser for the same problem first I heat treated and annealed it to stop it from bending and keep it's springiness, which worked for a while before it also bent

Next was to make a replacement from a high carbon steel (and heat/anneal it) which was better but still bent over time (about 30-40rds)

After the failures my plan was to replace the original extractor with the ABS type which is held by a pin, but they are difficult to get hold of so I made one which works very well and shows no sign of bending

I can't wait to get my hands on my Mauser now

The standard Marushin metal version of the M712 extractor simply "clicks" into place and has a habit of getting pulled out during firing. I'd bought my Mauser second hand and the locating slots on top of the bolt were worn making it even easier for the extractor to be pulled out of place.
The extractor is made from spring steel which had also lost its' ability to keep its' shape so bent on contact with the cartridge rim.

The ABS version has a better arrangement because the extractor is secured by a pin and it's spring loaded. The plan was to fit an abs version extractor but unfortunately sourcing one from Japan or anywhere else proved impossible.

I did manage to source a spring though thanks to Shazhib

8ace's post makes the modifcation sound a lot simpler than it was in reality, he really is too modest at times
Making the extractor from scratch is quite some task, Marushin probably stamp the basic shape from sheet steel then pass it through stamping and forming presses to bend the sides and claw over. This extractor is made by hand.
The Bolt was drilled to accept a securing pin, then drilling a recess to locate the spring before fitting the extractor itself.

I can't wait to try it out for myself

Thanks 8ace for your hard work and ingenuity

We aim to please

8ace

8ace wrote:

...they are difficult to get hold of so I made one...

I'm still laughing. I read the sentence, looked at the shape of the extractor at photo, thought for a moment how much effort it would take to shape such a piece of metal, heck, even such a piece of wood, then came to the same conclusion as Cerwyn ;-)

The tricky part was trying to hold such a small/thin part while working on it

Also the bolt stop (M8) broke so i made one of those as well

8ace you never cease to amaze me , am i glad you live just around the corner or what!!

claymore wrote:

8ace you never cease to amaze me , am i glad you live just around the corner or what!!

Where would we be without an engineer like 'ace surrounded by a pile of broken and knackered modelguns I reckon
It's worrying that some Marushin spare parts are becoming difficult to find, if not impossible at the minute.
I am looking forwards to firing my refurbished M712 immensely now, I'll be letting you all know how it behaves asap.

You'll remember my self destructing PPSh41 .. that's been repaired and reinforced too... watch these pages for News and Videos hopefully

well mate you've done it again,more brilliant machining skills .i hate ya /I agree with Claymore...i'm glad i live close

See ya soon mate..........got a big list

Kickback

Quote :

See ya soon mate..........got a big list

D'oh

Is there any other extractor that could be modified to fit M712?

By modified I mean rather simple things, like shaving off excess material, or maybe drilling a hole. I don't have machinery to process steel (except Dremel), so the original would have to be prett close ;-)

The only extractor that looks remotely like M712 is Mauser 98k. It just might be possible to use the thicker part (where "omega" comes) for drilling hole.