My 3622 journey

[Tack Driver 10]

Ran some tests and a shot string.
Pumped the gun to 3K psi for both tests.

With the stock hammer spring and Delrin spring guide:
07.90 CPHP 955 FPS, 16.00 FPE
10.65 BM 871 FPS, 17.94

Using the 362 hammer spring/mini Delrin spring guide:
07.90 CPHP 988 FPS, 17.12 FPE
10.65 BM 929 FPS, 20.41

Ran a shot string starting at 3000 psi down to 1800 psi.
Using BM 10.65 pellets and the stock hammer spring and guide.
Gun is very backyard friendly at 79dB.

[splitbeing]

That is a sweet tune. Nice work. Might not get much better than that.

Any luck fining an accurate pellet out to 50 yds? Was thinking the loose barrel might accommodate slugs or wide head pellets.

[Rick67]

I tried several different pellets with no success.
Even tried FTT 5.55 (triple nickle) pellets.
Pellets just slide down the barrel with minimal contact.
Wide bore with ghost rifling.

A LW MROD barrel would be golden, but it’s only 21” and might become too short for the tube post modification of the breech end.

I still have an extra one in .22 that I want modified to fit a 22xx/13xx breech 

[Tack Driver 10]

That is a sweet tune. Nice work. Might not get much better than that.

Any luck fining an accurate pellet out to 50 yds? Was thinking the loose barrel might accommodate slugs or wide head pellets.

I was a bit surprised myself at the long, flat shot string.
I was expecting 10-12 shots or so.
Sometimes the stars align and you get lucky.
Currently using a .120" TP so might try a .100".

The FTT 555s pellets barely transferred the rifling.
I tried .217, NSA pellets earlier and they dropped through.
A .218 brass probe starts to grab so.....
Ordered .219", 20 grain NSA slugs which are the fattest they offer.

[Tack Driver 10]

I tried several different pellets with no success.
Even tried FTT 5.55 (triple nickle) pellets.
Pellets just slide down the barrel with minimal contact.
Wide bore with ghost rifling.

A LW MROD barrel would be golden, but it’s only 21” and might become too short for the tube post modification of the breech end.

I still have an extra one in .22 that I want modified to fit a 22xx/13xx breech 

The Mrod LW barrel is about an inch too short.
I have a few and I wish I could have used one on this gun.

[Rick67]

I tried several different pellets with no success.
Even tried FTT 5.55 (triple nickle) pellets.
Pellets just slide down the barrel with minimal contact.
Wide bore with ghost rifling.

A LW MROD barrel would be golden, but it’s only 21” and might become too short for the tube post modification of the breech end.

I still have an extra one in .22 that I want modified to fit a 22xx/13xx breech 

The Mrod LW barrel is about an inch too short.
I have a few and I wish I could have used one on this gun.

Would a tube reduction hurt its shot count significantly?

[Tack Driver 10]

I tried several different pellets with no success.
Even tried FTT 5.55 (triple nickle) pellets.
Pellets just slide down the barrel with minimal contact.
Wide bore with ghost rifling.

A LW MROD barrel would be golden, but it’s only 21” and might become too short for the tube post modification of the breech end.

I still have an extra one in .22 that I want modified to fit a 22xx/13xx breech 

The Mrod LW barrel is about an inch too short.
I have a few and I wish I could have used one on this gun.

Would a tube reduction hurt its shot count significantly?

Definitely an option, it's fairly congested at the fill port.
I use a 90 degree fitting and a long custom made suppressor adapter.
The Mrod barrel would be 19 1/2" after machining.
The Challenger barrel is 21 1/2" so would need to take 2" off the tube.
The gun would definitely look better with a shorter tube.
Power could reduced slightly and still have a good shot count.

[SADave]

Not sure if it's been mentioned and not an idea I'd entertain for a while, but could one shorten the over length and add some plenum space with the 1377 PCP conversation kits sold on eBay?

Round about way to fit a shorter barrel that would create other problems ( shortening the stock, but it might work.

[SADave]

Checked pictures of the conversation kits and looks like it could work but I was wrong about being able.to get plenum space since  the valve and poppet are.connected to the attached.cylinder sort of like s hipac. 

[desertplinker]

I tried several different pellets with no success.
Even tried FTT 5.55 (triple nickle) pellets.
Pellets just slide down the barrel with minimal contact.
Wide bore with ghost rifling.

A LW MROD barrel would be golden, but it’s only 21” and might become too short for the tube post modification of the breech end.

I still have an extra one in .22 that I want modified to fit a 22xx/13xx breech 

The Mrod LW barrel is about an inch too short.
I have a few and I wish I could have used one on this gun.

Amazing talent and skill set you have. Just in case you want to shoot in .22 I might just try another Crosman barrel. I am getting one ragged hole at 20 yards, with stock barrel on the 3622, pretty much stock, just a lighter hammer spring.  I may have won the barrel lottery. Nice work you are doing.

[Rick67]

I tried several different pellets with no success.
Even tried FTT 5.55 (triple nickle) pellets.
Pellets just slide down the barrel with minimal contact.
Wide bore with ghost rifling.

A LW MROD barrel would be golden, but it’s only 21” and might become too short for the tube post modification of the breech end.

I still have an extra one in .22 that I want modified to fit a 22xx/13xx breech 

The Mrod LW barrel is about an inch too short.
I have a few and I wish I could have used one on this gun.

Would a tube reduction hurt its shot count significantly?

Definitely an option, it's fairly congested at the fill port.
I use a 90 degree fitting and a long custom made suppressor adapter.
The Mrod barrel would be 19 1/2" after machining.
The Challenger barrel is 21 1/2" so would need to take 2" off the tube.
The gun would definitely look better with a shorter tube.
Power could reduced slightly and still have a good shot count.

Thank you, sir 👍

[Tack Driver 10]

Ordered some 177 cal 10.3g and 13.4g FX pellets from Pyramid.
Need to make accuracy and velocity tests.
First max velocity/FPE test .
Pumped the gun to 3K psi.

Stock 3622 hammer spring, spring guide, PA -2 1/2 turns.
FX 10.3  825 FPS, 15.56FPE

Stock 3622 hammer spring, spring guide, PA max.
FX 10.3  880 FPS, 17.71FPE
FX 13.4  785 FPS, 18.83 FPE

362 hammer spring, mini spring guide, PA max.
FX 10.3  924 FPS, 19.52 FPE
FX 13.4  845 FPS, 21.24 FPE

Accuracy tests to follow.