.357 Gen 1 Mrod based pistol

[mackeral5]

Thanks Randy. 
I seal the valve to the breech similar to a WAR gun.  No need for barrel to breech orings though.  Metal barrel to metal breech seals perfectly, just like crosman did with the Bulldog.  If it does give a puff of air,  a bit of silicon grease on the barrel/breech before insertion is typically enough to seal it. 

Mike,
Thanks for the breech seal info! I was hoping it be would be something that I could do on my Prod breeches without much work.
I have extra Prod breeches setup for cal/barrel changes.
Have you thought about launching arrows out of the longer barrel? 
Randy

You're welcome Randy. 

here is a pic of a WAR transfer port on the right and one I made for a Cothran valve in a WAR gun on the left.  The WAR unit has orings top and bottom where it seals to the valve and breech.
 Believe it or not the brass one I made sealed on the bottom to the Cothran without an oring. 



this next pic shows you just how crude my work can be....  The one I use on this particular gun.  This is a brass sleeve with 3/8" icemaker line, both are in slight crush when the breech is tightened.  the 3/8 icemaker line has been drilled out to .290ish.  It ain't perfect but it seals and flows.  I have disassembled/reassembled this dozens of times now, with no leaks...

[screwwork]

All of my transfer ports are made from poly tubing and get good seals on them, my largest is transfer port is 5/16" OD for the .25 cal mini-rod and the arrow barrel.
I may play around with the brass sleeve though for better support of the poly tubing.   Thanks for the tips.

[mackeral5]

All of my transfer ports are made from poly tubing and get good seals on them, my largest is transfer port is 5/16" OD for the .25 cal mini-rod and the arrow barrel.
I may play around with the brass sleeve though for better support of the poly tubing.   Thanks for the tips.

I started using the brass tubing reinforcement on my QB's where the transfer port becomes exposed and unsupported when you start getting up in size.  It seems to work ok for those of us without real fabrication skills/equipment.

I didnt respond to your question about arrows.  The airbow concept hasn't quite peaked my interest yet, so I haven't given it much thought.  Something about how loud the guns are without an LDC, as compared to releasing an arrow from a bow/crossbow almost silently.  I may be wrong but that is my perception of the concept.

[mackeral5]

In anticipation of  a part arriving next week I converted back to the Prod trigger group and short barrel.  Based on the "is it a pistol?" discussions I put the short barrel back on.  I rummaged through my junk parts and found an old QB front sight and a random dovetail clamp on rear sight.  an ebay  1/8 bspp pressure gauge arrived, so I installed it as well. 



Now we have a 3lb 13oz pistol.

in this configuration, adjusting the SSG can vary tunes from a 717, 692, 667 fps 3 shot string to a 619, 636, 650, 641, 624, 606fps 6 shot string with JSB 81gr pellets.  There is a longer 500fps tune/string, but once again I find myself out of pellets....

[FuzzyGrub]

In anticipation of  a part arriving next week I converted back to the Prod trigger group and short barrel.  Based on the "is it a pistol?" discussions I put the short barrel back on.  I rummaged through my junk parts and found an old QB front sight and a random dovetail clamp on rear sight.  an ebay  1/8 bspp pressure gauge arrived, so I installed it as well. 



Now we have a 3lb 13oz pistol.

in this configuration, adjusting the SSG can vary tunes from a 717, 692, 667 fps 3 shot string to a 619, 636, 650, 641, 624, 606fps 6 shot string with JSB 81gr pellets.  There is a longer 500fps tune/string, but once again I find myself out of pellets....

    

[mackeral5]

A shipment from Canada arrived today....one of the last 2 missing links to this build.







It wasn't always planned to be a pistol, this is more along the lines of the original intent.

Gippeto made the Gen 1 Mrod buffer tube adapter.  It is threaded 1/2-20 all the way through.  A very slight interference fit in the tube, absolutely ZERO wobble. 

1 out of 2 missing links are no longer missing, still waiting/looking for the shorty tube.  Then the puzzle will be complete.

[YEMX]

That's a beauty right there!!!  I may have to put out a WTB ad for a Gen1 .25 Mrod!   

[FuzzyGrub]

He did very nice work on that adapter.    I might need one for a gen2 tube. 

I think that looks allot better vs using the Armada chassis.

Are you still able to use your SSG?

[mackeral5]

Hopefully the short tube will come in the next few weeks....  At that point I can fit either the 16" barrel and 350cc bottle or 12" barrel with the 220cc bottle.  Toggling between Powerhouse and Simplified Balanced Valve format will only require degassing, removing the barrel and removing the tank block to access and unscrew the piston carrier from the Cothran valve.  Then either add or remove the rod from the poppet stem to convert from one format to the other. 

I gave Gippeto/Al a very crude drawing with dimensions from a Gen 1 end cap/adjuster that had the degas threads drilled and fully tapped to 1/2-20, and that's what he designed the adapter to.  My SSG fit perfectly. 

At some point I'll need an AR buffer tube adapter for a Gen 2, but whomever needs one first will have to work through the design with Al.  It shouldn't take much to adjust for the additional breech mounting holes and length inside the tube.  He is great to work with and does beautiful work. 

I waffled back and forth over Prod trigger or Armada chassis for my upcoming Gen 2 build....   The Armada chassis is certainly the less costly of the two.  But I think I prefer the simplicity of the Prod trigger and buffer tube adapter....

[YEMX]

If only we had a reliable source for a Prod conversion sear!

[mackeral5]

If only we had a reliable source for a Prod conversion sear!

Agreed.  It is weird that I was able to order one at the same time you did, my order was fulfilled but yours wasn't....Perhaps they will become a little more organized in 2021???

[Gippeto]

The more I look at that short barreled version the more I like it.

The drawing was completely adequate, and Mike was a pleasure to deal with. My schedule makes shop "play" time sporadic, and he was a patient fellow which is always appreciated.

Feel free to shoot a pm when ever you're ready and we can look at the Gen 2.

Regards,
Al

[YEMX]

Agreed.  It is weird that I was able to order one at the same time you did, my order was fulfilled but yours wasn't....Perhaps they will become a little more organized in 2021???

I'm glad you caught that-  You ordered yours AFTER I did, and actually got them- I never even got an email back... 


I can't stop looking at the short version with the AR adapter...  I keep thinking about getting a folding adapter and an adjustable stock like this:


Combine it w/a AR grip adapter and a precision rifle grip?  Oh man.  Nice compact little hammer!!

[FuzzyGrub]

The more I look at that short barreled version the more I like it.

The drawing was completely adequate, and Mike was a pleasure to deal with. My schedule makes shop "play" time sporadic, and he was a patient fellow which is always appreciated.

Feel free to shoot a pm when ever you're ready and we can look at the Gen 2.

Regards,
Al

Will do.  I'll provide info on the "standard" G2 end cap, and what is also needed.  In general, it goes deeper into the air tube and has two 4-40 breech screws, similar to Prod.

I will need one extra hole in the bottom for the trigger assy screw.  On a G2, I'll have to drill additional holes to move it forward about 1/4". 

[mackeral5]

The more I look at that short barreled version the more I like it.

The drawing was completely adequate, and Mike was a pleasure to deal with. My schedule makes shop "play" time sporadic, and he was a patient fellow which is always appreciated.

Feel free to shoot a pm when ever you're ready and we can look at the Gen 2.

Regards,
Al

Will do.  I'll provide info on the "standard" G2 end cap, and what is also needed.  In general, it goes deeper into the air tube and has two 4-40 breech screws, similar to Prod.

I will need one extra hole in the bottom for the trigger assy screw.  On a G2, I'll have to drill additional holes to move it forward about 1/4".

 

That would be awesome to have the extra hole for the Prod trigger group built into the design.....

[FuzzyGrub]

I had looked at the oem end cap, which does extend far enough, wouldn't be too hard to drill and tap for the trigger screw.   Now me doing that in SS, much lower chance of success.   

[mackeral5]

I had looked at the oem end cap, which does extend far enough, wouldn't be too hard to drill and tap for the trigger screw.   Now me doing that in SS, much lower chance of success. 

 

BTW, the adapter is made of 4130, not SS....

[FuzzyGrub]

The polishing fooled me. 

[Dairyboy]

Great build Mike! I have a Gen1 .22 Mrod I picked up a few months ago I haven't even shot. I've toyed with the idea of making it into a short carbine in the 35" range but would need a short tube also. Gives me things to ponder on. Again though very cool build!

[FuzzyGrub]

Agreed.  It is weird that I was able to order one at the same time you did, my order was fulfilled but yours wasn't....Perhaps they will become a little more organized in 2021???

I'm glad you caught that-  You ordered yours AFTER I did, and actually got them- I never even got an email back... 


I can't stop looking at the short version with the AR adapter...  I keep thinking about getting a folding adapter and an adjustable stock like this:


Combine it w/a AR grip adapter and a precision rifle grip?  Oh man.  Nice compact little hammer!!

I like the looks of those.  On Prods, with straight adapters, had the opposite problem, too little comb, and had to use high or extra high rings.  This, having a higher breech. might be ok as is.