Trail NP barrel removal?

[USMCSPRINGER]

I know, I should be watching the superbowl!!

I have this idea of eventually getting a LW barrel for my Trail NP....I am wondering what would be the best way to remove the barrel from the breech block???

thanks in advance!

**GOING BACK TO THE GAME**

 

[Kailua]

This must be a fad.  Basic same question was asked in the Engineering Research and Development gate recently with this answer.


Re: Barrel Replacement
« Reply #1 on: January 13, 2013, 03:50:34 PM »

    Quote

I've done it on other Crosman and RWS breakbarrels. Not for the faint of heart 

What I did was remove barrel & block from the compression tube and cut barrel off about 2" above block. Reamed  the barrel out until it was no more than 1/8" thick then bake to about 450 degrees. Once it comes out of the oven I put it in a vice (leather wrapped to keep warm and to not mar with vice jaws) and then put a pipe wrench on the barrel and turn it. At that point they usually break free.

If that doesn't break them free then I turn a mandrel for a air hammer, heat breech block up again and drive barrel out. Installation is similar - heat block, freeze barrel that has just a slight interference fit and jam them together. Usually have to machine the end of the barrel before reassembly for the breech seal.

Very do-able, just gotta wanna ...

[USMCSPRINGER]

uh, sure... I will knock that out this Saturday...

wow, I knew it wouldn't be easy...BUT...

not sure if my wife would let me use the oven for that...   

thanks for the info! I am off to check out that R&D gate....

[tilbertscott]

I was looking at the crosman parts diagram and it looked like it was all one piece and the baking style wouldn't work.

[tilbertscott]

some pics of the gun now in the pic of the scratches on the breach where is a correct side to give a good filing to fix this barrel droop...? would a new seal there be a good idea to get too?

[map8660]

Greetings,

Just an FYI,  I got a new nitro venom, same sort of barrel setup,  My barrel was so loose I could actually twist it slightly.
i tore it down, removed the pivot bushing and the 1/8 inch barrel lock pin and was suprised I could actually move it.  By twisting it just came loose.
No threads, just is pressed in.  I should of mic'd it to see if it had a taper, I really don't think so.

Well I had another one that I wanted to pull apart,  I heated that sucker up, there was some sort of glue coming out, could be something like locktite.
I sprayed freeze mist in the barrel, still wouldn't budge.
I gave up but I have to wonder if I got it any hotter if it would of come loose.

The barrel I had that did come apart had some of the 'glue' on ti.  I think that it just of got assembled without much.

It looks like the barrel is mounted in the breach and then the barrel is finished up machine wise as a assembly.
Not really made to take apart. 

The locking pin didn't seem to have any taper on it as well.

I'm just guessing here, perhaps they dope the barrel and locking pin with something like red locktite.
I was surprised how rough the turned barrel surface was.

I've dealt with red loctite and when it comes to taking things apart after it was used it means breaking out the torch (the read and green wrench).
Perhaps if it was really hot and kept hot it could be twisted out, hot... the stuff they use may actually act as a lube of sorts.

They must make these fast, it shows. 
At least the barrel assy is cheap enough thru Crosman.

I'm not a machinist by any means, just thought I pass what I found.

Oh yes,  I should add that the replacement barrel assy, after cleaning, was a smooth as silk, pushing a pellet thru it had no sticky spots at all.
Before I installed  the replacement barrel I re-crowned it and also touched up the breach side for easier pellet insertion.
It shoots a whole lot better.

Take care and Happy Shooting,

Mark

[map8660]

Scotty,

I filed my breech, the barrel droop was terrible on mine, on the new barrel as well.
I took a felt marker to 'paint' the breech face and just carefully filed it a little at a time.  It seemed the very top of the breech did the trick for me.
Pulled the breech seal out  before I started and went real slow; took a couple hours.
Someone here has a pic looking down the chamber tube out to the barrel showing his droop, mine was as bad if not worse.
Had the scope shimmed in the back for some time till I tackled filing / truing up the breech face.
It also affected mine in that I was able to remove a shim that the factory had installed.

Take care,

Mark