www.MG42.us

going to try the first live round tommrow and see if it will fire.

every thing moves and goes click. I even got it to fire a primed piece of brass. I'm sure
that there is a long way to go but if it can fire one round it should be a start.

I've been wainting for your project to get to this point.
It was nice knowing you buddy.

you will be missed

Really though, I believe you will have good results.
Keep us posted.....

Jason, what did you do for a coating?

skip

im sure it will work out just fine...
keep us posted!

who did your work, oh yeh good luck

Jason. go to church and pray real hard. LOL have fun with that build of yours!! I'm racing my buddy, between his HK21 and my SA42 build....to see who gets to the range first! Best of luck! Slowfinger

Jason, we are all waiting!!!!!! Good Luck

ok it goes boom!

the first problem was ejection. the ejector spoon would slide into the coller that the buffer pushes forward. tried several differnt things and they all interfeared with the firing pin after a few rounds. before I figured this out I spent alot of time fiddling with several firing pin return springs. I ended up welding a coller on the spoon to keep it down and it seems to work.

the major concern is the primer is flowing into the firing pin hole. the aussie flows back, and winchester factory ends up with a hole in the primer. the protrusion of the pin looks ok but it is a little sharp. this will take some more messing with to get right. has anyone else had this trouble?

all and all it was a great day and I sure need to take some time off of work so I can play more.


BTW I love new rank

congrats

Good job! All your hands and fingers are still attached. I'd call that a successful day. Your primers problem could be one of several issues...Primer flow can be caused by several issues...Number one is excessive headspace/pressure. Have you checked the HEADSPACE???? May need to find a barrel/bolt-head combo that is more agreeable/compatable. Did you adjust out the booster cone to help vent some pressure (too late in the cycle to do much good but may help). Second possiblity is firing pin is too long and/or sharp. It may punch to hard and thin the metal to dangerous levels. Do the cases show other signs of high pressures???Bulges, cracks, heavy indents from the extractor like the exctractor is having to really force the round from the chamber? Beside the hole or buldge in the primer, how does the rest of the primer look?? Is it deformed or does it look hammered flat instead of the chamfered primer edges of an unfired round.

When the ejector spoon rides up and over the ejector did it stick or wedge in place? What modification did you make to leave enough room for this to occur?? (I ask because I don't want to make the same mistakes).


Enquiring minds wat to know!!!

Way to go Jason. Probably at this point it needs a little tinkering, but great to hear that someone has one up and running.... Keep up the good work....

congrats jason,
wecsog graduate, and still has all his fingers and toes! sounds like its just minor tweaking left to fix....
its a nice feeling to build something from scratch.......

Jason,

make your firing pin more blunt would be the my 1st step, I will post pics of 3 different ammo types with 3 different results from the same set-up, lastly when all fails barrel changes/bolt head. You can just swap out parts from bolt head to bolt head. Most of my expierences have been ammo related/firing pin profile. The more pointed perform better in hard primers. On the 308's most will fire with lightest possible strike, sometimes only with fp protusion of .02 or so.

The following is in order firing with different ammo types. Portugeese, Lake City, and I think Indian. The lake City shot the hottest and blew every primer, Portugeese shot exceedingly well with no signs of excessive pressure, the Indian shot well with no problems.

I blunted the firing pin and just got back from a test fire.

the primer still flowed back but the dimple in the center was gone and it looked much better. the fp is now protruding .036.
I think I'll round it a little more and try again but it is gettin late and I still have a lot of work to do on the computer.

btw there are no other signs of pressure on the cases so hopfully I am on the right track. this thing need run good because just test firing is a Hoot

Jason,
What is the diameter of the firing-pin-hole in the face of your bolt?...and the diameter of the firing-pin? (It may be that you have a worn Bolt-Head-"Face" where the firing-pin-hole is now "over-sized"......?)

Next question would be: Are the primers starting to "back-out" of the primer-pockets in the cases? (Not where they are hit by the firing-pin...but around the entire outside edge of the primer). Good or lose "head-space" on that barrel/bolt combination?

Last questions:
1: Booster front-hole-diameter? (8x57mm or 7.62mm NATO)
2: Length of Barrel-Bearing?
(Note: Last two questions for a survey going on.....thanks).

Be safe, RichardS.

3 more tests and I think I'm sure its the protrusion of the fp.

been taking the fp down slowly and every time the primers look better. its now down to .022 and there is just a little flow back. tommrow nite i'll run it down to .020 and see what that looks like

the brass still shows no sign of pressure ie primer backing out or flatening of the primer edge, marks on the head, or widening of the base.

Blanksguy, when I get a chance I will do the measuring of the bbl bearing/booster just dont ask for millimeters

jason wheres the pic of your toy?

I want to wait until there is a big pile of empty brass laying under the gun to take a pic or two.
I think the sun shining off the brass and smoke rolling off the bbl will make a great first pic.

don't forget the charibs with brass horns and singing angles