The Last (?) Grail Gun - 12G FRT

[Alaska_Shooter]

Today’s range day. It ran really well

 

[strobro32]

We are going to need another bucket for the bucket list.

 

[ericthered]

Has a little push to it, don't it lol!

 

[strobro32]

Much better with the Wally world #8 than the 00 buck and slugs. I felt those 215 rds of high brass in the morning.

After cleaning it this morning, the Tharpe aluminum trip in the rear of the carrier had domed the the washer that is used to secure it. The bolt was still tight. I decided to drill a 1/8" cross hole through the carrier and trip to secure them with a spring pin.

Chris told me they wanted the bolt, washer and lock washer there to put a preload on the bolt. He also said it would be good to go if I cross pinned it without the trip retaining hardware so that is what I did. It has a flat carrier now so I can test other buffers and springs.

Also my AR12 now pivots up like it should. No more pulling both pins to disassemble.

I would like to test a AR10 kynshot hydraulic buffer and some flat springs in a Just Right Carbine buffer tube.

Mike, have you tested your 25 rd drum yet? Does it use dummy rounds?

 

[mak91]

I got the first chance to test it last night and the tower cracked from the recoil :-( Went back to the drawing board and I added as much extra material to the area that it broke that I could and also changed the feed angle slightly to get it to feed smoother/better. Back to another few days of printing. Right now I'm using 5 3d printed dummy rounds as a follower and it has last round bolt open functionality. I'm shooting lefty since my right hand is f'ed up so I don't have a frt installed yet.

 

[Alaska_Shooter]

the Tharpe aluminum trip in the rear of the carrier had domed the the washer that is used to secure it.

Mine did this also. I replaced it with a thicker washer but I love the cross pin idea!

so I can test other buffers and springs.

Please keep us posted

 

[strobro32]

Today’s range day. It ran really well

What did you do to get the 10 rd mags to work? Mine are very unreliable even on semi. The only difference seems to be the front of the 10 rd mag has some material ground off, like there were trying to remove flashing but took too much off by about .020-.025".

 

[Alaska_Shooter]

I did nothing special. I just loaded them and shot them

 

[strobro32]

Does the rib on the front of your 10 rd mags look like they removed material? They rock in the magwell more than the 5rd.


10 RD

5 RD

 

[strobro32]

I'm wondering if it's better to shim the 3-10 rd mags or to make a magwell adapter and pin it in the lower to use unmodified MKA 1919 metal mags and drums. I think the mag release slot is in the right place.

 

[Alaska_Shooter]

An adapter to use 1919 drums would be sweet

The tabs all look the same. Two five round mags on the left. 10 rounds on the right

 

[strobro32]

Well, PSA says the mags "are not eligible for warranty service." I used some epoxy puttty to build them up so we shall see. I will test today.

 

[strobro32]

The modified 10 rd mags work better but still not as reliable as the 5 rd mags. I wonder if JTS thought that making them lean the other way was better. I will try that next. I don't mind cutting stuff up if it leads to giggling.

 

[strobro32]

Tested the new forward leaning 10 rd mags today. They were much worse feeding with #8 shot. I'm really leaning toward a MKA 1919 mags and drums magwell adapter now. I have a 5rd 1919 magto play with.

 

[mak91]

So my drum works but doesn't hold up to the recoil. You can see the crack across the feed tower after 5 rounds. There is no way to add more material there. Maybe a different filament type would do better but I'm going to put this on hold for now. I have a 1919 drum on the way I'll see what might be done with that with Matt's mag well adapter Idea.

 

[strobro32]

I knew you would make one. This seems like a job for a 3D wizard! What 1919 drum did you buy. I'm on the fence.

 

[mak91]

Promag 15 rounder to start with.

 

[ericthered]

Can you chop a 5 rounder mag up and use it as the feed tower?

 

[strobro32]

Yes. Although 5 rd mags are already made to connect to a base plate or other component. The bigger problem is how to attach that short tower to a drum without making it look like I did it. The reviews on drums out there makes it look like this is a failure point that current MFGers have too. I think the better solution is to use a magwell adapter to use existing 1919 mags and drums.

 

[mak91]

Yes. Although 5 rd mags are already made to connect to a base plate or other component. The bigger problem is how to attach that short tower to a drum without making it look like I did it. The reviews on drums out there makes it look like this is a failure point that current MFGers have too. I think the better solution is to use a magwell adapter to use existing 1919 mags and drums.

I agree. I made my drum tower way thicker than the factory jts mags where I could and it still cracked in two spots, the mag catch ( which I can't add any material to ) and the interface to the drum (which I would fix if it wasn't for the mag catch issue). I think there is a reason the drum manufacturers are using metal towers or the tower is modeled into the drum body as one piece.