.38/.357 prototype

[bruski]

I will get some measurements and post them.

 

bruski

[bruski]

Here is what I have for the Bruce Feed Base. The hinge pivot on the left should be lower between the mounting flange and the radius piece silver soldered. The back plate not shown is attached to the back side of the block with the two wedges on it. Mine is as wide as the block and is 12 inches tall. The magazine is as wide as the block and is about 11 inches tall with a ball bearing in the top pivot with two rows as close to each other as possible.

 

bruski 

[Sparky_NY]

I got the top cover made, with the hinge and the ejection port with hood.     I just have not cutout for a mag yet.

 

I see the drawing has the sloped ears for the bruce magazine on top,  will that same base also function with a straight stick mag?        Didn\'t the original ones work with either?

 

Really appreciate the info and drawings !!       I am ready to cut metal as soon as I get my head wrapped around the design/theory.

[Sparky_NY]

Went back and looked at the pics of the bruce you posted.       Am I correct that the mag is not removable?       Looks like the mag and top cover are a assembly.

 

It appears you pretty much eliminated the single stack section like the original had and went non removable.    Am I getting this right?

 

Here is the pic I was comparing to.

[bruski]

The base could work with a stick mag if an adapter of some sort was made. Mine is just for the swinging double row bruce type of mag.

 

bruski

[Sparky_NY]

Been very quiet here lately so I figured I would make a little noise.

 

Been sidetracked working on the gun doing outside spring yard work and such.    I have done cad work on the Bruce feed mag along with research on the subject.    Very close to making some chips.

 

In research, watching many many videos, I have not seen a single case were the mag automatically switched columns when one goes empty.    I\'m pretty sure the original intent/design was to automatically switch BUT I cannot find a single example where it actually worked.     Not a real big deal, it still holds a lot of rounds and switching columns is effortless.

 

So.......   I have been thinking.    IF it will not switch automatically anyways,   why not make THREE columns of ammo ?       Fire the center column first,  then switch to a outside row, then the other outside row.       Thinking it would allow a lot of rounds and even make the mag shorter for the same capacity.

 

Crazy idea?     Anyone actually see one switch columns automatically?

[gbull]

Not crazy at all. I think to make them switch on their own would be great, but possibly difficult to pull off. They were always a two man gun, a gunner and a loader. The broadmoor drum always looked more adaptable to a mechanical indexer. Ten round slots, indexed with each complete revolution of the barrel assembly. There were some photos a while back of one that looked like it might work.

[Sparky_NY]

Since I moved south 6 years ago,  I had not set up my reloading equipment.     Getting close to test firing on the 357 gat and ammo could get very expensive without reloading SO...   I dusted off the press and set things up.     I had not reloaded 357 before so had to get dies and such.    I have 200 very mild 357 cases loaded up (medium 38 spc power level).    I have a hornady LNL progressive reloading press with bullet and case feeders now equipped for .38/.357

 

Yesterday, went back to the shop and the gun.    Extracting works great BUT ejection is not working as expected.   I used the round pin in the pan method for ejection.    It stands the round up but does not kick it out.    I am pretty sure its because I placed the pins too far rearward on the pan.   I looked this morning at some of cutters videos using the ejection pin in the pan and his pins are indeed further towards the chamber.    Right now, I am leaning towards drilling new holes in the pan to locate the pins further towards the chamber,  probably today.

 

Getting the ejection nailed down is one of the last steps before live ammo tests.

 

SO.......... whats everyone else doing with the 357 project?    Been extremely quiet for a while.      I see cutter got sidetracked on 22 bolts and another 22 gat for testing purposes but what about the others?       Gotta keep the 357 project alive !

[Cutter]

Sparky , \" I looked this morning at some of cutters videos using the ejection pin in the pan and his pins are indeed further towards the chamber.    Right now, I am leaning towards drilling new holes in the pan to locate the pins further towards the chamber,  probably today. \"

 

This is my  3/32  pin placement.

One size may not fit all.

[4171]

Still working on my bolts. Slow going on a manual machine!😎

Mike

[Sparky_NY]

 

Sparky , \" I looked this morning at some of cutters videos using the ejection pin in the pan and his pins are indeed further towards the chamber.    Right now, I am leaning towards drilling new holes in the pan to locate the pins further towards the chamber,  probably today. \"

 

This is my  3/32  pin placement.

One size may not fit all.

 

What I have seen is that the pin must be even or slightly forward of the front edge of the extractor when the bolt is fully retracted.       IF its too far forward of the extractor the shell rim can fit in the gap and lock things up tight.   Like many things on these guns,  there is a very narrow window that works.     Another 5 or 6 guns and I might have all these concepts nailed down  LOL

 

Looking again at Cutters drawing, I realized the stroke of the bolt also matters.   I am guessing Cutters bolt retracts further into the carrier than mine,  the net effect is the same as the pin being further forward.

[maccrazy2]

If you guys get a set of plans together for one of these I would be a buyer. I’m not going to get ahead of myself but I would like to build an affordable to shoot centerfire gun some day

[Sparky_NY]

If you guys get a set of plans together for one of these I would be a buyer. I’m not going to get ahead of myself but I would like to build an affordable to shoot centerfire gun some day

 

Most of us do not work from plans,   we use cad/cam to draw the gun and its parts and all the dimensions are there.    Cad has the benefit of being able to \"assemble\" everything in the computer and check clearances and tweak dimensions easily.      That said, we have the cad files which boils down to the same thing as plans except no instructions.   The forum here provides real good instructions on each of the parts.   The centerfire guns are really just bigger versions of the 22 ones which actually makes them easier to machine,  you are not working with such tiny parts.

[bruski]

The ultimate 357 would have extra stroke on the bolts like cutters. I believe his stroke is .125 more than mine is and it has plenty of extra room to clear the ejector pins and feeding the 357 cartridges. The 38 special cartridges drop and feed well enough.

 Sparky, you are correct on the pin placement needing to be a little further forward if you have room and still clear the rims on feeding.

 

bruski 

[Sparky_NY]

Its funny how on both my 22 and 357 gats I made the pan length and bolt stroke what SEEMED like more than enough YET at the final stages on the guns I wish I had made the stroke/pan a little  longer.   They both worked out fine and functioned ok but clearances got a little tighter than I would have liked.

 

Same thing goes for bolts,  what seems like plenty big always seems to get tight when you cram in firing pins, extractors, grooves in the bottom and such things.   My 357 has 3/4 dia bolts and the wall between the firing pin bore and the extractor pocket is pretty thin.

 

As I said before,  this is only 2 gats for me so far,  maybe when I get to 6 or 7 I will learn the areas that really need to be paid attention to !     I may do one more but not for a couple years anyways,  I have the barrels for a .410 shotgun gat.    IF I build it someday it will be just a shooter, no brass or anything fancy.

[Sparky_NY]

Well its official,   its a gun !      Fired 17 rounds thru it this morning included a 3 round fast burst.      I 3d printed a short magazine for testing.    Going to fire some more today after my pulse slows a bit and I have a bite to eat.

[maccrazy2]

Let’s see some video!

[Sparky_NY]

Let’s see some video!

Still embarrassed for that.   On a 2x6 redneck test cradle still.    Going to do a couple small refinements.     Needs a guide on the top cover, sometimes rounds catch on the way into the chamber, easy fix.    The firing pin hits look almost too deep,  going to try some lighter springs which will also make it crank easier.   The cocking switch is too stiff, hard to pull out.     THEN I can do a 6-7 round burst with the test mag and will maybe make a video.

 

Fired some more rounds ,  31 total today,  all fired nice and ejected great.   I\'m happy,  less fine tuning that I expected will be needed.

[4171]

Jealous 😀

[4171]

Hoping I figured out[attachment=10953:IMG_2522.jpg] how to download pictures! I finished profiling the bolts, it work better than I thought it would. Thanks for the all the advise Jerry!

Mike