M1928 80% Build?

[Wolfpack331]

Ive done the search and have mixed feelings.
I would like to make a CALI LEGAL out of an 80% and 1928 Parts Kit.
Has anyone done this? Opinions?
Be critical but be open minded.

[saki302]

Thompson? Fahgeddaboudit.

The only parts you can use from your parts kit are the wood, and a few odds and ends. The semi is a totally different animal.

NOTHING major from the full auto fits the semi- they intended it that way!!

-Dave

[Wolfpack331]

DAMN! I was hoping to make a semi outta a true WWII weapon.
Oh well ...next!

[JPglee1]

DAMN! I was hoping to make a semi outta a true WWII weapon.
Oh well ...next!

You can, depending on how much effort and $$ you want to spend...


You'd need to engineer a "split bolt" to allow the OEM open bolt to run as a closed bolt (mill slot in bolt, add striker, remove F/A sear trip and block F/A position in trigger group)

You'd also need to add a blocking bar to the receiver and modify the bolt accordingly to prevent a F/A bolt from being inserted. You could run some 1/4" keystock across the receiver in front of the barrel/trunnion and then notch the bolt to not hit the key stock (like on a semi UZI) or you could run keystock down the length of the receiver and mill a slot in the bolt to accomodate it.

I being overly cautious would probably do BOTH, then it would be pretty difficult to use a F/A bolt w/out some serious machining. Definitely not something the average person would be able to pull off w/hand tools....

Lastly you'd need to add a longer 16" barrel and make sure the OAL would stay at 30" w/the stock removed *OR* permanently attach the stock....You would also need to either make a "wing grip" like a monster man grip, or remove the pistol grip OR you could use a 20rd mag locked in place w/the PG....


ITs not impossible, but if you dont own your own mill/lathe, you'll probably spend a couple hundred bucks on machine work.

Where there is a will and a deep pocket, there is always a way


J

[saki302]

Just a FYI- I looked into this a few years back.

The Kahr/AO Semi Thompsons do several things to stay legal- the receiver is TOO SHORT to accept the full auto bolt- the rails are actually cut higher than they would be on the FA. This means, if dropped in, the FA bolt sticks out the bottom about 1/8" and will not work. I don;t even think the FA bolt could be machined to fit since so much material would have to be removed. They also have a shelf on the receiver bottom which prevents the FA lower from sliding on, and the recoil system is 2 small springs with guide rods, plu a center striker spring- the FA one has one spring only.

The Semi lower is totally different internally- to the point each is unrecognizeable when viewed from the top (I had a chance to compare the two side by side at the S.A.R. gun show). A modded FA lower may not pass muster with the ATF, be careful. At a minimum, the selector hole should be welded SHUT, and the rest modified to take the existing semi parts.

Also, a welded block in the upper may not pass ATF muster either- remember, that's NOT how they made the Semi legal- the upper is completely different dimensionally.

Unless you can obtain a correct-dimension semi upper, I wouldn't touch it- too risky. There's no approval letter for a built semi, and a blocking bar could theoretically be made to work with a FA bolt (just mill or file corresponding slot into the bolt).

There's a reason they designed the semi the way they did, and went to such great lengths to change it, IMO.

If you want more WW2 parts in the gun, I would look into having the lower welded & machined to work with the semi components. I don't feel the risk of the full build is worth the rewards.

-Dave

PS- DO NOT EVER EVER EVER lock a 20 round mag in place on ANY non-AW build. A fixed mag greater than 10 rounds is AUTOMATICALLY an AW and HIGHLY illegal.

[Wolfpack331]

I had the idea when I saw a 80% reciever up close. Its pretty much just a chunk of metal. Not hollowed out at all, no rails etc. so you could probably just mill it for a semi bolt and just modify the lower? The only authentic parts are the stock, barrell and lower. All would be fine except you would need to modify the lower. Right? I am really just curious as I do enjoy getting dirty and having a cool project. My other desire/dream/fascination is doing an MP5 flat, either traditional or pistol. I know I know WTF. Im not looking for trouble, Im in the Mil, and I appreciate certain weapons to the point I just gotta have em. I do own a BW5, FAL, and Scout. But Im NEVER satisfied. DAMN DAMN DAMN

[saki302]

Here's the problem- the semi receiver is shortened on the bottom- it isn't the bolt channel alone, the rails which the lower slide onto are higher up than on the FA. Thus, if you re-machined the FA 80% upper to work with the semi bolt, you would not have ANY rails to hold the lower receiver.

If the receiver you saw had no rails on the outside, it wasn't an 80% receiver- that's more like a 50%. You have to make sure the thickness is enough at the high point to cut semi rails on it- it might not be.

I should have taken a picture, but I didn't have my camera with me at the time (I think there are signs at SAR saying 'no photos'). I had an old class III FA gun apart next to a W. hurley semi-auto

-Dave

[JPglee1]

Well I get what you guys are saying and YES you are all correct....

BUT you gotta look at what you're comparing... a mass produced "semi" copy sold to anyone who can buy them. The company is gonna cover their arse, I know I would.

As long as it will not accept a FA bolt you're good to go. Look at the Semi STEN kits out there, some use a "regular" bolt milled for a striker and smaller OD on the bolt and thats it...

Also have you seen the semi auto Sterling MK6 parts??


SEMI auto MK6 bolt/striker

Those parts are basically FA parts altered as I have suggested, in fact you can actually build a SEMI "STENling" with those parts and its quite easy/legal...

Now I guess the Tommy is more eviler and more popular so I can see the concern, but to me if the bolt is a different dimension, the feedway is blocked with key stock and the trunnion has a blocking bar, thats THREE hurdles to clear to get a FA bolt in, and you'd still have to add F/A sear mechanism into the equation to make a MG (unless you let it run slam fire, yes Im aware of that too) As a forth hurdle you could run an unenclosed bolt face which would also help your cause.

Anyway you guys can do as you will, I personally would go for a Semi Thompson if I wanted one (I dont have much fascination in Tommys)

As one last share n tell, check out the Semi VS Full UZI parts:

http://files.uzitalk.com/reference/pages/FAconversions.htm

If you take the time to read that page you will see theres not *a lot* different from a full to a semi uzi... The 2 biggest factors are the block bolt and the unenclosed bolt face.

If you could pull of a 1/2 circle bolt face on a Tommy that would be even better.

I guess Im an optimist. I have to be, I read stuff like this:

http://www.gunco.net/forums/f50/belt-feed-ak-47-a-34001/index51.html

http://www.weaponeer.net/forum/forum_posts.asp?TID=6166&PN=1

http://www.weaponeer.net/forum/forum_posts.asp?TID=6756&PN=1

Thanks for taking the time to read my posts, and SORRY for the "20rd" Typo, NEVER EVER lock a hicap mag into a fixed mag build in CA.

Thanks

J

[saki302]

The Semi Sten SAS3 design (approved) has a reduced diameter receiver which will not fit a full auto bolt. Also, no one uses full auto bolts (converted) in semi builds because they found it was near impossible to turn down successfully with a lathe (they go out of round or face ends up cockeyed, and that design (BSA) was never ATF approved).

I'm not familiar with the Sterlings- AFAIK no one made a semi 80% kit for builds because of the complicated bolt- those were complete guns- I'm unsure if the originals were open or closed bolt too.

The UZI is also an ATF approved design, obviously, because it was produced that way by UZI It's not just the restrictor ring, there are a few other things which keep it from being an easy conversion (including a larger bolt at the bottom).

If you're using an auto-spec receiver, you're asking for trouble, IMO, not to mention none of the semi parts will fit the auto lower. As I said, if you see them open side by side it's a wholly different firearm.

-Dave

PS- Belt fed AK is F-IN AWESOME

Yes, there are those guys that an build anything out of anything

[Wolfpack331]

Thanks that was the insight I was looking for....next idea...
I just got back from reno and picked up 9mm and 308 HK Flats. These I know I can do in some fashion or another.