Have I gone too far? Beeman 1358

[Kerndtc]

Valve porting, significant trigger work, honed to 2k grit on all mating surfaces and swapped springs to bring it to a 5 oz first and 8-9oz second stage with a clean break, made a light weight hammer for it, 1/5 the weight of the factory one. Now I'm going to bottle it.

From factory it was only 19fpe, and had a downward trending shot string, cliff like.

After porting I was shooting 30fpe very easily. Then it was too loud, so I designed, manufactured and installed a compact moderator for it.

I've got it tuned to shoot 26fpe at 1500psi. Not looking for serious power, just enough to take game comfortably to 50-60 yards.

Haven't don't barrel lapping yet, but that's on the to do list after I do all the work.

The light weight hammer has been a game changer, significantly less hammer bounce, and will help me use less air when regged at 1500psi. Also, makes the gun way more quiet.

I ordered the material to sleeve down the cylinder to accept the bottle adapter I use. But they sent the wrong one. Will have to wait another week for that to arrive.

I did a tiny bit of accuracy testing and it looked promising, I kind of just wanted to get a nice little inexpensive bullpup together.

The value of the work far exceeds the cost of the gun itself. I guess that's what you get when you just love to tinker?

[SpiralGroove]

Valve porting, significant trigger work, honed to 2k grit on all mating surfaces and swapped springs to bring it to a 5 oz first and 8-9oz second stage with a clean break, made a light weight hammer for it, 1/5 the weight of the factory one. Now I'm going to bottle it. amer

From factory it was only 19fpe, and had a downward trending shot string, cliff like.

After porting I was shooting 30fpe very easily. Then it was too loud, so I designed, manufactured and installed a compact moderator for it.

I've got it tuned to shoot 26fpe at 1500psi. Not looking for serious power, just enough to take game comfortably to 50-60 yards.

Haven't don't barrel lapping yet, but that's on the to do list after I do all the work.

The light weight hammer has been a game changer, significantly less hammer bounce, and will help me use less air when regged at 1500psi. Also, makes the gun way more quiet.

I ordered the material to sleeve down the cylinder to accept the bottle adapter I use. But they sent the wrong one. Will have to wait another week for that to arrive.

I did a tiny bit of accuracy testing and it looked promising, I kind of just wanted to get a nice little inexpensive bullpup together.

The value of the work far exceeds the cost of the gun itself. I guess that's what you get when you just love to tinker?

Cameron,
Looks like a fun project I'd be interested in .
Let us know about it's 50 yards accuracy when done.  I've enjoyed modifying a few QB78/79 to HPA.

[Kerndtc]

Valve porting, significant trigger work, honed to 2k grit on all mating surfaces and swapped springs to bring it to a 5 oz first and 8-9oz second stage with a clean break, made a light weight hammer for it, 1/5 the weight of the factory one. Now I'm going to bottle it. amer

From factory it was only 19fpe, and had a downward trending shot string, cliff like.

After porting I was shooting 30fpe very easily. Then it was too loud, so I designed, manufactured and installed a compact moderator for it.

I've got it tuned to shoot 26fpe at 1500psi. Not looking for serious power, just enough to take game comfortably to 50-60 yards.

Haven't don't barrel lapping yet, but that's on the to do list after I do all the work.

The light weight hammer has been a game changer, significantly less hammer bounce, and will help me use less air when regged at 1500psi. Also, makes the gun way more quiet.

I ordered the material to sleeve down the cylinder to accept the bottle adapter I use. But they sent the wrong one. Will have to wait another week for that to arrive.

I did a tiny bit of accuracy testing and it looked promising, I kind of just wanted to get a nice little inexpensive bullpup together.

The value of the work far exceeds the cost of the gun itself. I guess that's what you get when you just love to tinker?

Cameron,
Looks like a fun project I'd be interested in .
Let us know about it's 50 yards accuracy when done.  I've enjoyed modifying a few QB78/79 to HPA.

The 78/79 platform is a great HPA platform! I've had a great time playing with those rifles too. The first National Grand Prix plaque I received in pistol I earned was with a Beeman 2079a. Very usable and rugged platform.

[Toddspeed]

For a tinkerer there’s nothing better than making something basic and generally considered unimpressive, act like something much more than that.

What kind of bottle adapter do you use?

[avator]

I'm going to dig into my 1358 today. I haven't even cleaned the barrel yet.
Cameron, I'm interested in that moderator... would you consider making another one?

[SpiralGroove]

Cameron,
What volume will the air tube hold - 150cc's?

[Ribbonstone]

Good project so far....that's a reasonable power level for most air gunning, and all that really counts is having fun and keeping both your hands and mind busy.

19 foot pounds?  PCP equivalent of asthma...all the power was there, just couldn’t move the air.

Because the bottle hasn’t been adpated/hung on the tube yet, going to guess the testing was done with the regulated bottle tethered to the tube.  So basically, the full tube volume as plenum for testing.

Looking at that scope mount location, adding a bottle would still leave a pretty large plenum. Larger is a whole lot easier to deal with than too small a plenum.

So the end results, once bottled, won’t be far off the tethered results….within the range of normal adjustments.

[Kerndtc]

For a tinkerer there’s nothing better than making something basic and generally considered unimpressive, act like something much more than that.

What kind of bottle adapter do you use?

I totally agree!

I'm using the Umarex Gauntlet Bottle adapter.

It's designed for a 19mm ID airtube, but this one has a 22mm Id. I'll be using metal as a bushing loctited in place with 638, then it will be drilled and pinned with four carbon alloy m4 screws that hold the gauntlet block in place!

[Kerndtc]

I'm going to dig into my 1358 today. I haven't even cleaned the barrel yet.
Cameron, I'm interested in that moderator... would you consider making another one?

I still make them! They are on my eBay store.

Benelliboym1 is my eBay name.

[Kerndtc]

Cameron,
What volume will the air tube hold - 150cc's?

Roughly 160 ccs total.

Good project so far....that's a reasonable power level for most air gunning, and all that really counts is having fun and keeping both your hands and mind busy.

19 foot pounds?  PCP equivalent of asthma...all the power was there, just couldn’t move the air.

Because the bottle hasn’t been adpated/hung on the tube yet, going to guess the testing was done with the regulated bottle tethered to the tube.  So basically, the full tube volume as plenum for testing.

Looking at that scope mount location, adding a bottle would still leave a pretty large plenum. Larger is a whole lot easier to deal with than too small a plenum.

So the end results, once bottled, won’t be far off the tethered results….within the range of normal adjustments.

Hey!

I'll be inserting the bottle adapter as far back as I can, it will be resting against the scope mount/ barrel/ air tube support section. Leaving me with enough plenum for a big bore.  About 96cc. I will be able to easily bring it up to 30-35fpe comfortably if I want. But 25fpe is fine for a nice little truck gun. Also if I tune it to be just after the knee of the curve, I should be able to utilize that large plenum as some off reg shots!

I used the full tube for testing, should be identical results with a tube loss of 60CC or so.

[avator]

Thank you Cameron... order placed.

They do come in black, right?

I watched the video but I didn't have the speakers on the laptop so I couldn't hear if you stated that.

[Kerndtc]

What is recommend to people who want more power out of this gun and to have a more usable shot count would be to chop the hammer spring maybe 2 coils, take the breech off (two barrel set screws, main breech block screw in the magazine tray, rear screw u see the cheek piece) then tapping it off with a rubber mallet.

Your orings for the barrel seal will be damaged  almost guaranteed. I used some 3/8 id/ 1/2" od 1/16 cross section orings handy for replacement. They are 10mm/13mm 1.5mm cs orings normally. But these work great and don't scuff badly on the way back in. I use a little silicone grease on installation. Also, take some 400-600 grit paper and make a cone, slide it inside the breech where the barrel slips in and soften that sharp edge.

I can't remember if there are set screws holding the barrel in place, but beneath the the side picatinny rails there are clamping screws that hold it snugly in place. Remove those and pull the barrel out. You'll look into the valve exhaust and see that it's almost like the manufacturer didn't drill all the way down and left a restriction to choke down the power. I removed the valve and disassembled the whole gun for this step, but if you're careful you can size the exhaust hole with the valve in place. I don't recommend it. But it's possible.

You can take your drill bits and see what one is closest in size to the valve exhaust and drill the rest of it out. This will give you a dramatic increase in velocity.

I also, did a bstaley mod by installing a 7/8" od oring with a 1/16 cross section between the hammer and the metal cylinder that holds the breech in place 

Wish I took pictures of all these steps.

[Kerndtc]

Thank you Cameron... order placed.

They do come in black, right?

I watched the video but I didn't have the speakers on the laptop so I couldn't hear if you stated that.

I can make it glossy black, or carbon fiber vinyl wrapped. Thanks for the order, just received notification

[avator]

Carbon fiber please.
Thanks

[avator]

Mine is the 1358 but I think it said it didn't matter.

[Kerndtc]

Mine is the 1358 but I think it said it didn't matter.

They are the same shroud and barrel threads. Drop on for both!

[avator]

Thanks again.
Happy Holidays.

[Kerndtc]

I chopped the tube!

Got the sleeve material to bring the 21.99mm id air tube down to 19mm.

This will allow me to use the bottle adapter I have on hand.

Unfortunately had to give the project a rest while visiting with my in laws, but the sleeve has been cleaned, sized and grooves machined into the surfaces to allow for the Loctite 638 to grab and set.

I'm not relying on the Loctite for holding the sleeve in place while under pressure, it will have 4 m4 steel screws pinning it in place with the adapter.

I'm looking forward to getting this complete. Only a few hours left and I should be done.

Barrel is completely removed, and will be lapped. The reducing sleeve is curing in place, and my last touch will be a SSG. Should make this gun sip air. Should be one of a kind

[Ribbonstone]

Like the project….visually,  thought your picture was a good indication...would have just moved the bottle straight up from that picture to make the fore end inletting easier and not foul the under lever cocking.

[Kerndtc]

Like the project….visually,  thought your picture was a good indication...would have just moved the bottle straight up from that picture to make the fore end inletting easier and not foul the under lever cocking.

That's exactly it.

Trying to keep it as simple as possible, keeping the linkage system as near to factory as possible. If the front end is too heavy I might swap to a 0.22l carbon fiber bottle.

Since I'm working with a drill press and a hobby 7x10 lathe I will be drawing up the jig in cad and 3d printing the part to slip over the cylinder as a guide for my pilot drill. I've done this on a few builds and it helped significantly.

Cam