GatewayToAirGuns.org    Donation

All Springer/NP/PCP Air Gun Discussion General > Machine Shop Talk & AG Parts Machining

Repurposing rifle barrels for PCP

<< < (2/2)

NonGrata:

--- Quote from: Goldxxx on December 26, 2023, 01:28:55 PM ---Duane38, I have some blanks in the same .357 1-20 twist so I possibly start with one of those. Is this slug an off the shelf purchase? Could I possibly buy a mold to cast my own?

NonGrata, air rifle pellets or slugs need to be able to easily be pushed through a rifled bore with little resistance? The only thing I have had to push through a barrel lately is a bronze brush. Would it go through with light resistance like a tight cleaning patch? I once had a squib 9mm round get stuck in a Browning Hi Power barrel. It was a bear to remove with a hammer and brass rod. And I only had to move it 4 inches

--- End quote ---
a tight cleaning patch is probably a good way to describe the amount of drag you should feel once the pellet or SOFT slug has entered the barrel. There will be a happy medium but if it doesn't fall thru the barrel on its own or get stuck in the first inch it will be right in there somewhere.

Remember a pellet has a skirt and it will be more forgiving than a slug in more than one way as mentioned above.

Yes .35 cal pellets are available just Google.

Duane38:

--- Quote from: Goldxxx on December 26, 2023, 01:28:55 PM ---Duane38, I have some blanks in the same .357 1-20 twist so I possibly start with one of those. Is this slug an off the shelf purchase? Could I possibly buy a mold to cast my own?

NonGrata, air rifle pellets or slugs need to be able to easily be pushed through a rifled bore with little resistance? The only thing I have had to push through a barrel lately is a bronze brush. Would it go through with light resistance like a tight cleaning patch? I once had a squib 9mm round get stuck in a Browning Hi Power barrel. It was a bear to remove with a hammer and brass rod. And I only had to move it 4 inches

--- End quote ---

I found that pellets work rather well.  All the various "slug" type of rounds in my supply are simply too tight. 

The barrel blanks I have were purchased from Green Mountain fairly cheap.  40-50 bucks each time. 

The key is in the lead in the chamber.  Some use 2 degree reamers.  I simply set my lathe compound to 2-2.5 degrees start the cutting right before the transfer port.  Before the transfer port, the barrel breech is machined to the pellet diameter + a few thousands.  That way the pellet head and/or skirt aren't pre-compressed/deformed. 

JPSAXNC:
I've used .30 cal and 9mm PB barrels, but I lapped out most of the rifling (a long and tedious job) because the grooves are to deep compared to air rifle barrels.

Duane38:

--- Quote from: JPSAXNC on January 08, 2024, 09:56:09 AM ---I've used .30 cal and 9mm PB barrels, but I lapped out most of the rifling (a long and tedious job) because the grooves are to deep compared to air rifle barrels.

--- End quote ---

Really?  Are you "fire lapping"?  I don't spend much time on that element.  I do know a that a current barrel is just too tight.  With that, purchased a .30 cal FX  smooth twist barrel and made a shroud.  This is for the msp project.  So far, very impressed with how it turned out.  Very light and an FX smooth twist.  Post pending on the build. 

JPSAXNC:
Hi Phil, No not fire lapped, I used solid SS. lapps of increasing diameters and 400 grit compound, finishing with finer grits. This was before there were any pellets .30 or lager commercially available.

Navigation

[0] Message Index

[*] Previous page

Go to full version
Powered by SMFPacks Media Embedder
Powered by SMFPacks Alerts Pro Mod
Powered by SMFPacks Ads Manager Mod