16,5" barrell Prod update

[Tucobenedicto]

A few weeks ago i started a topic about this project,it taked some time and work but here it is.
I started from a 2260 18" barrell.
I made a spacer from an aluminium rod to move forward the original shroud (a custom shroud is not part of the project now).
I decided to made a brass "thimble" for the barrell port and the probe o ring,the barrell is cutted at 16,5",turned down to fit the thimble and slotted to accept an o ring.
I made a new compact air stripper and glued it in place with epoxy.
I noticed a misalignement of the valve port in the tube,so i made a new transfer port from teflon bored out at .180"
Assembled today and tested with my crony,no much time,but it seems to peak at 928fps with 15,9 JSB's,gaining 95fps respect to the original barrell,a bit over 30FPE,not bad.

[fivestar45]

Nice job Fabio..
I take it that the barrel slips into the thimble right up to the T/P ?

[screwwork]

Sweet, nice job on the barrel! Now for some for range time to see how she shoots.

[Tucobenedicto]

Nice job Fabio..
I take it that the barrel slips into the thimble right up to the T/P ?

The hole in the thimble is 9mm dia flat end and the barrell leans on it.

[Tucobenedicto]

Thanks Randy,i hope the barrell is good,the crown was a bit rough,so i deburred and polished it,i smoothed the loading side accurately.
Now i need to shot some serious string to tune the hammer properly under the "knee",i need to test it with 18,1 JSB's too because i want to switch to them as soon i go out of 15,90's.
I hope i can re zero and test for accuracy this week end,unfortunately is a bit rainy this days here.

[Tucobenedicto]

Little update,after some string i tuned the hammer for a more reasonable speed,slighty under 900fps with 15,9 pellets.

[Tucobenedicto]

Reassembled and scoped.

[Rick67]

Looks fabiOlous, Fabio sir  ..

[Tucobenedicto]

Thank you Richard 

[Tucobenedicto]

I must correct some numbers,i claimed a speed increase of 95fps,but i compared a peak speed with a tuned "down the knee" speed.
The real increase is about 67fps,compatible with the 10-15fps per inch rule.

[Hawkeye51]

Fabio

Molto bene!

[Tucobenedicto]

Grazie Mike,thank you.

[Tonycalves]

Great job Fabio!  Perfect looking carbine. Great platform to customizing.

What are the final #s?

[Tucobenedicto]

Great job Fabio!  Perfect looking carbine. Great platform to customizing.

What are the final #s?

You mean the cost?
Difficult to say,i still had the LDC and the regulated bottle from other projects,the stock is a softair one,say 20 bucks,the new barrell about 50 shipped,the drop block and the stock adapter are made by me.
This kind of project are part of the fun for me,burn some money is one of the collateral damages of this forum 

[Tonycalves]

Sorry meant Velocity and shot count.

The cost on these things gets silly. My .25 Mrod has over $2100 into it over time. AND IT'S STILL AN MROD! Could have gotten a American Air Arms for that $.

[Tucobenedicto]

I merely changed the barrell lenght,regulator setup as before,about 150 bar and porting at .165,it shooted 15,90 pellets at 833fps about 50 shots per fill.
Now it shoots the same pellets at 899fps,don't know if a longest barrell has effect on shot count,the weather is rainy and i taked only a few shots for a rough re-zero,the barrell seems ok,at 10 meters indoor it place pellet on pellet,we will see..

[FuzzyGrub]

Looks good!   

Custom length DIY barrel lengths for the Prod will be easier once crosman releases the schematic for the Fortitude.  Just cut and re-crown.

[KnifeMaker]

MIkie likes it!


Knife/Mike