397 vs. 2289

397 vs. 2289

Joined: March 1st, 2002, 12:22 am

January 7th, 2011, 8:51 pm #1


I love both these guns. But the 2289 has a small valve, not much velolcity. But the breech and barrel are not soldered to the pump tube, which allows parts swapping and custom work.

The 397 has a much bigger pump mechanism, but yer stuck with the soldered on barrel and breech.

So how do I get the best of both these guns into one unit? I'd love to get the 22xx breech and shrouded barrel onto a 39x mechanism..... Just thinking out loud, mainly........

EDIT: I have an AFU 397 barrel/pump tube that I'd be willing to donate to the cause......


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the Lunatic Fringe of American Airgunning
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Last edited by dan_house on January 7th, 2011, 8:52 pm, edited 1 time in total.
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Joined: April 1st, 2009, 3:18 am

January 7th, 2011, 9:13 pm #2

...you could do it. Remove the tube and breech from the Benji (unsolder it). Solder on the Crosman breech being sure to align the transfer holes centered. Next, lathe two oring grooves around the Crosman 7/16 barrel, one before and one after the transfer port. Next, make a new front end plug that is 1/2" or longer than the existing Benji plug. Use a barrel band in the front now so the front of the Crosman barrel can be supported. The extra length end plug is needed to ensure the pump stroke arm outward does not contact the band.

You now have a fixed breech, but caliber swapable Benji air rifle. The two orings are needed since the transfer seal will not be accessable. I would also o-ring the Benji valve to prevent air loss.

Now you need a way to cock the rifle. Easy, mill a slot in the side of the tube and drill/tap the striker to accept a cocking handle.

As it stands currently, a Crosman breech cannot be used as a screw attached unit. The screw holes (screws rather) will in fact interfere with the striker and spring; the alignment of the Crosman breech screw holes and port...

This doable and is pretty easy to do.

I was going to do it, but decided on my 9mm pumper project (new 4130 tube, QB78 breech, 5/8" 9mm barrel, modified Benji valve, Mac1 billet lever and adjustable piston). Haven't decided on the QB trigger pack or to use the 2260 trigger pack as of yet.

Also, do me a fovor and check the inside diameter of the Benji tube for me, please-oh-please. I have gauges, but they only go down to 1/32".

"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."

Last edited by Duane30 on January 7th, 2011, 9:17 pm, edited 1 time in total.
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Joined: March 1st, 2002, 12:22 am

January 7th, 2011, 9:38 pm #3


thanx Phil!

I had not considered cocking it, but would have run into it some point... Was thinking it thru only from an air path perspective...

I had been contemplating a riser plate, thick enough for the breech screws to attach to, yet not allow them to protrude into the striker path. Solder the riser plate to the tube.

About the 2 oring barrel mount.... wouldnt the space between the rings-dead space at this point-- bleed off some of the air? better off to cut the barrel back past the TP? or would you need to cut a new leade at that point?

back to the drawing board in my head.....


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremecy
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Joined: April 1st, 2009, 3:18 am

January 7th, 2011, 10:08 pm #4

...will not be accessable once the breech is soldered on - just like the Benji is now. The o-rings act as the seal along with the o-oring around the valve, much like how the QB78 barrel - it is o-ringed for a seal.

The lead in should be fine as it is. The barrel will be removable. If caliber swap is the idea, all barrels will need to have o-rings on them.

I'll sketch up a picture for you and post it. Give me a few minutes...

"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."

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Joined: April 1st, 2009, 3:18 am

January 7th, 2011, 10:56 pm #5

Okay, here is what I am meaning for the barrel o-rings and added o-ring to the valve:


"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."

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Joined: March 1st, 2002, 12:22 am

January 7th, 2011, 10:59 pm #6


ok, that cleared a lot up.

ah, more to ponder on.

I'll get the ID measurements for ya tonight


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremecy
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Joined: April 1st, 2009, 3:18 am

January 7th, 2011, 11:12 pm #7



"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."

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Joined: April 12th, 2002, 5:26 am

January 8th, 2011, 12:51 am #8

thanx Phil!

I had not considered cocking it, but would have run into it some point... Was thinking it thru only from an air path perspective...

I had been contemplating a riser plate, thick enough for the breech screws to attach to, yet not allow them to protrude into the striker path. Solder the riser plate to the tube.

About the 2 oring barrel mount.... wouldnt the space between the rings-dead space at this point-- bleed off some of the air? better off to cut the barrel back past the TP? or would you need to cut a new leade at that point?

back to the drawing board in my head.....


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremecy
lap the barrel to the receiver...I did that with a QB PCP with no leakage issues.

A couple of barrel band type clamps might handle the receiver attachment...you might even fab them to be reminiscent of a Sheridan Model A receiver.

A rear cocking mechanism (SSP250?) might save some work over a side cocking knob..though if you make it a side pumper, your cocking slot is already done (mostly)

The dual o-ring on the valve is an off the shelf item from crosman..it's the AS392 valve rear section.
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Joined: April 1st, 2009, 3:18 am

January 8th, 2011, 1:09 am #9

Did you put the abrasive between the barrel and tube and force it in place? Or did you just JB weld the barrel in?

"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."

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Joined: March 1st, 2002, 12:22 am

January 8th, 2011, 3:29 am #10


"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."

.775

give or take my measuring skill and cheap calipers


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremecy
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