.357 Gen 1 Mrod based pistol

[mackeral5]

Spent some time lobbing those 110gr slugs at my 75 yard 4" gong.  For kicks I put on the Emperor and Extension.  Made for an obnoxiously long combo, but it is nearly silent.  The 110gr are running around 515fps. 

Pfft....wait for it...wait for it....DING.  This is more fun that I ever expected.

[YEMX]

So cool!!  I can't wait to get mine back together!!

[mackeral5]

So cool!!  I can't wait to get mine back together!!

That pic was for your benefit, regarding the polish adapters.

[YEMX]

That pic was for your benefit, regarding the polish adapters.

I appreciate it!!  I did in fact place an order today.  I just wish he made one that wasn't so... squared off.  One with a taper like yours would be much better.  But I'm not really complaining- this route will be far easier to accomplish!

FWIW: I did start a conversation with Darko about a possibility of a Mrod 25/35.  I think the mag would be deep enough for the JSB 82g and those 88g GT slugs, but not much more.  Should be able to hold 5 shots.  Just my eyeballing it.  He is going to look into it. 

I think that having a mag available would solidify what to do with that other short tube, drop block, and .22L bottle.     

Having a mag would certainly be a VERY welcome addition!!  I hope this comes to fruition!

[FuzzyGrub]

There has been some additional back and forth on the mag, so I'd say he is taking a real look into it.

I have some of those Polish made adapters for 1/2-20, and they do look good with the CF over the barrel, like what Mike has. 

[YEMX]

There has been some additional back and forth on the mag, so I'd say he is taking a real look into it.

I have some of those Polish made adapters for 1/2-20, and they do look good with the CF over the barrel, like what Mike has.

A mag certainly would be a fine addition to a .357 converted Mrod, for sure!  I may have to build a Gen1 Mrod up myself...  Caliber changes would be far simpler...

The tapered adapters do look quite nice over the CF, but the one that I bought, made up for a 18mm O.D. barrel isn't tapered.  It's squared off at the back.  But on the plus side, I won't have to do a thing else w/the adapter.  The through bore is .374".  I think a bit of looks is a good trade off for simplicity. 

[FuzzyGrub]

This is one that is more squared off.  I think it looks good with the CF sleeve. 

[YEMX]

Oh!  That DOES look really nice!!

Silly question- does a Cothran valve interchange between a Gen1 and Gen2 Mrod?  Or does the valve have to be generation specific? 

[FuzzyGrub]

I think that CF was 2mm thick.  If using the more typical 1mm, I agree the slight taper would look a little better.

On the Cothran valve, I think the answer is "yes" but would have to go find a picture.  Crosman Gen 2 valves work in G1.  The differance in the outer body, is just the relief for the trigger assy screw.  The G2 valve has a slot, which covers both positions. 

[mackeral5]

I think that CF was 2mm thick.  If using the more typical 1mm, I agree the slight taper would look a little better.

On the Cothran valve, I think the answer is "yes" but would have to go find a picture.  Crosman Gen 2 valves work in G1.  The differance in the outer body, is just the relief for the trigger assy screw.  The G2 valve has a slot, which covers both positions.

The I used 13x16mm CF for this build.   With 16" and shorter barrels it is still very stiff. The Polish adapters start becoming squared vs. tapered once you get up to an 18mm ID, IIRC.  I have a 17mm on order for another project, it is tapered I believe.

Don's Mrod valves work on both Gen 1 and Gen 2 Mrods as well as WAR Flex and WARP models. 

[YEMX]

...Don's Mrod valves work on both Gen 1 and Gen 2 Mrods as well as WAR Flex and WARP models. 

That's good to know!! 

[mackeral5]

I repurposed some parts from other projects that didn't work out the way I wanted and was able to finish the 8.5" barrel with CF sleeve and a muzzle brake. 



I've found it is very responsive to the SSG.  With gap, as one would expect it is very efficient but not performing in the upper end of the energy range  I can slightly preload the SSG and get  more power, without becoming too inefficient, and pretty flat across 3-4 shots. 

Using JSB 81gr pellets with a small amount of SSG gap it does 7 shots 590,596, 600, 610, 615, 605,590.  remove the SSG gap and slightly preload the hammer against the valve and it gives 4 shots 662, 667, 664, 642 fps. 

That little 4 shot tune of around 75fpe is a pleasant surprise with the short barrel.

[YEMX]

Those are some fine numbers!

[mackeral5]

I am still exploring my options, here is another combination of Marauder Lego's. 

Remove the Prod trigger, replace it with an Mrod trigger and old beat up stock.  Swap the barrel to a 18" GM .25 with the choke cut off, that has been sleeved with CF  and one of the Polish adapters on the muzzle.  Switch over to a  .22 bolt sleeved up to .25 with brass tubing.  Add the tank block and 220cc tank.  Quiet down with a Tatsu. 

All of this is done without entering the power plant nor removing the breech.

After adjusting the SSG, the end result is right at 39" long and produces 35-40 shots of 55fpe with JSB 34gr. 



In the end I believe I will build 2-3 guns based on this powerplant, with one being a dedicated .357 pistol.  There are 2 key components that are long awaited and will help finalize decision making once they ultimately arrive--an ultra short tube that butts the tank block up against the valve and a custom end cap that accepts an AR buffer tube/stock. 

[YEMX]

Yep- that's about what my build will look like, but with a synthetic stock.  My tube will be a touch shorter at 10.5", and the barrel is only 18" or so.  That'll place the muzzle just past the end of the tank, w/the reg in place.  VERY nice build indeed!!

[mackeral5]

Yep- that's about what my build will look like, but with a synthetic stock.  My tube will be a touch shorter at 10.5", and the barrel is only 18" or so.  That'll place the muzzle just past the end of the tank, w/the reg in place.  VERY nice build indeed!!

Thanks Tom.  Hopefully this thread is demonstrating the potential of Gen 1 Mrods.  Once you get away from sealing TP to barrel they become very modular.   

Here it is converted back to 16" .357 Brod configuration.  Almost exact same length as above--39" with a Ronin. 

In this configuration it can be dialed from a bunch of 80 fpe shots to a handful of 130fpe shots by simply adjusting SSG gap....

[FuzzyGrub]

I am still exploring my options, here is another combination of Marauder Lego's. 

Remove the Prod trigger, replace it with an Mrod trigger and old beat up stock.  Swap the barrel to a 18" GM .25 with the choke cut off, that has been sleeved with CF  and one of the Polish adapters on the muzzle.  Switch over to a  .22 bolt sleeved up to .25 with brass tubing.  Add the tank block and 220cc tank.  Quiet down with a Tatsu. 

All of this is done without entering the power plant nor removing the breech.

After adjusting the SSG, the end result is right at 39" long and produces 35-40 shots of 55fpe with JSB 34gr. 



In the end I believe I will build 2-3 guns based on this powerplant, with one being a dedicated .357 pistol.  There are 2 key components that are long awaited and will help finalize decision making once they ultimately arrive--an ultra short tube that butts the tank block up against the valve and a custom end cap that accepts an AR buffer tube/stock.

You really have that Powerhouse valve and SSG dialed in. 

[screwwork]

Yep- that's about what my build will look like, but with a synthetic stock.  My tube will be a touch shorter at 10.5", and the barrel is only 18" or so.  That'll place the muzzle just past the end of the tank, w/the reg in place.  VERY nice build indeed!!

Thanks Tom.  Hopefully this thread is demonstrating the potential of Gen 1 Mrods.  Once you get away from sealing TP to barrel they become very modular.   

Here it is converted back to 16" .357 Brod configuration.  Almost exact same length as above--39" with a Ronin. 

In this configuration it can be dialed from a bunch of 80 fpe shots to a handful of 130fpe shots by simply adjusting SSG gap....

1st, sweet looking lego gun.  How are you sealing TP to the barrel and how do swap bolts for cal change without removing the breech?
 

[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. 

[screwwork]

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