www.MG42.us

I have been working on an improved semi bolt conversion. The main problem to be overcome is binding of the firing pin due to the bolt head / locking wedge cocking. to overcome that I have designed a totaly enclosed firing pin assembly. the ejector rides on top of the sleeve and does not come in contact with the firing pin. the sleeve rides in the ejector bushing in the rear and ensures the locking wedge is square with the bolt head.
this totally eliminates any friction on the firing pin.
I have done some preliminary testing and am making some improvements based on the tests. Once I have all the dimentions correct I will have parts made. this wil be a drop in conversion for those of you with a converted bolt, all that wil need to be done is drill out the feed stud in the ejector sleeve.

Nice Work! I'm Interested in 2!

I've been testing a duplicate of that for over a year now with great results. prototypes were made with 5/32" A2(?) steel rod with collars hard soldered on to hold up the ejector tube and limit the pin position, figured to get the finished pin machined from one piece for better durability and looks.

I've popped around 700 rds of .308/7.62X51 with it of every make i could find , but mostly SA and wolf for fun .
then moved onto 8MM , currently at around 400 rds of various makes and years only one dud , but a good primer dent. A lot of that i credit to the light mass of the 5/32" pin , it doesn't have much inertial to sap energy and is easy to temper with a B tank.

Try -

• 4.92" OAL
  .44" from front of pin to start of front collar
  .98" from rear of pin to start of rear collar

These dimensions will prevent the pin from being assembled back-wards,won't setting off "soft" primers, and MOST important no more possibility of OOB because the energy of the hammer will be absorbed by the firing pin holder unless the bolt is locked.

Now that is an excellent, reliabel, and SAFE design. Kudos !

DI, this is different, it is a sleeve permanently attached to the wedge. The FP is inside, the sleeve rides in the ejector sleeve in the rear. this makes the wedge close straight and there is no way for the pin to bind it is supported in the front by the wedge and in the rear by a bushing. The rod is .180" for rigidity, the fp spring is inside. I think some of the oob problems are due to the style of wedge being used. there are several different designs and some have a small shank that can cause improper lock up in a semi.

My bad pirate , they look identical assembled.
no my sleeve floats on the 2 collars never thought about attaching it to the firing pin holder, guess i just preferred being able to interchange with a new one if i felt motivated.

the thing you need to do to stop OOBs cold is find a way to stop the hammers energy from reaching the primer unless the bolts locked up. doesn't matter which firing pin holder you have , as long as its not too badly worn. the front collar at .44" with an original FP won't reach the primer until the bolts locked up. that means the energy is going into the firing pin holders rear not the primer of an unchambered round.

Great looking setup! Any idea what sort of time frame we are looking at before it will be ready to order? Also, what FCG setup do we need for it, and will the rest of the bolt conversion parts be available again when you do offer it for those of us who don't have our semi-mods done yet? Thanks.

dagobert wrote:Great looking setup! Any idea what sort of time frame we are looking at before it will be ready to order? Also, what FCG setup do we need for it, and will the rest of the bolt conversion parts be available again when you do offer it for those of us who don't have our semi-mods done yet? Thanks.

I have 2 versions to test, I hope to do that in the next couple of weeks. this setup will work with either fcg and will be retrofittable to bolts I have converted. It is basically a drop in set up. As far as more bolt conversion parts if there is enough interest I will get some extensions made, but I don't want to spend several hundred dollars right now for parts that will sit here.

I have several projects in the works that need to be completed, the 8mm hopper loaders, the spade grip setups the ar15 fcg box and possibly a FAL fcg box to weld on a grip. I just finished the last of the partsfor the 7.62 x 25 pistol kits and need to get them shipped to fund all this R&D.

Please post when you are ready to receive grip sticks and bolts for mods.

Orion Arms wrote:Please post when you are ready to receive grip sticks and bolts for mods.

Will do, right now I have to many things to finish before taking on more work and I don't want peoples parts sitting here.

I got to test 2 versions of the new bolt setup thursday. one with a one peioe firing pin and the other with a 2 peice.
the single peice pin started having problems after about 20 rounds, I didn't harden the pin and the end was mushroomed over and further inspection showed the pin bent as you can see in the photo.

the 2 peice setup worked great till the ends of the pin started to mushroom and bind. It was a stupid mistake on my part to not harden them before testing. Brazing on the spring shoulder softened up the rods and making these up over a period of a few weeks I forgot the critical step.

The setup works 100% with the fal fcg and about 80% with the ar fcg. I ordered some heavy duty ar hammer springs but didn't get them in time for the shoot. I think with a little more tinkering I can get this new setup to be 100% with either fcg.

I am going to do one more test with hardened parts then get some parts made. I will be doing a limited amount of these for sale.

Pirate--

I am interested in 2 sets when they are available.

--fjruple

Pirate wrote: I have done some preliminary testing and am making some improvements based on the tests. Once I have all the dimentions correct I will have parts made. this wil be a drop in conversion for those of you with a converted bolt, all that wil need to be done is drill out the feed stud in the ejector sleeve.

Pirate:

Do you think your setup will go into one of PBB's SA bolt conversions also?

Thanks,

MikeD

MGMike wrote:

Pirate wrote: I have done some preliminary testing and am making some improvements based on the tests. Once I have all the dimentions correct I will have parts made. this wil be a drop in conversion for those of you with a converted bolt, all that wil need to be done is drill out the feed stud in the ejector sleeve.

Pirate:

Do you think your setup will go into one of PBB's SA bolt conversions also?

Thanks,

MikeD

If you can drill out the stud in the back it will.

Well...In that case, I'll get in line for one or two.

Thanks,

MikeD

Gentlemen I am new here and am getting in the parts for my own semi build on a wiselite reciever. I was looking at your build and have some questions. I was thinking of welding the sleve ( sorry if I don't know all of the names) that pushes the edjector forward. Then drilling it out for the base for the firing pin. I would have to cut the cam pin and weld each stud in place to hold the sleave in place.

Does the cam on top of the bolt have to turn or isn't it important.

Not really answering your question,but... Go to Pirates site,the link is on all his posts.There are some excellant tutorials there that will take you through the differant mods you will need to do.Lots of good info.Good luck,and welcome aboard! ---bil

mp40guy wrote: I was thinking of welding the sleve ( sorry if I don't know all of the names) that pushes the edjector forward. Then drilling it out for the base for the firing pin. I would have to cut the cam pin and weld each stud in place to hold the sleave in place.

Does the cam on top of the bolt have to turn or isn't it important.

the cam doesn't have to turn , its better if it does (less wear) but not important.
The rest of your question has me confused . please don't do anything to yor bolt until we can understand what your doing. the bolts are getting expensive and i don't want you to ruin one.

If you plan on sleeving the bushing it creates binding with a one peice firing pin, unless you drill it off center so the pin is straight., if you use a 2 peice setup it doesn't matter.