Chronograph results for 2240 valve extension

With stock valve stem, stock weight valve spring, and stock weight hammer spring. Valve has no porting or polishing. The breech is Cothran Machine with hollow bolt. Gun has a 12 inch barrel. Velocity Adjuster was unscrewed all the way, so no extra tension on the spring. Also used one of Anthony's Protops to test the gun with 12 gram cartridges.

Temp 65 degrees using co2 12 gram
14.66 grain Beeman FTS domed
CED Millennium Chronograph

535
529
530
540
533
533
529
530
523
525
525
525
523
520
515
506

I will be testing again tomorrow when it is warmer. I also replaced the stock stem with a polished ground down one. I haven't started porting the valve, and I am over 9 ft/lbs for at least 1 shot.

Here you go. Same gun with stock valve, springs, and stem.

488
476
474
460
453
453
455
458
457
440
424

This string was also at 65 degrees.

With stock valve stem, stock weight valve spring, and stock weight hammer spring. Valve has no porting or polishing. The breech is Cothran Machine with hollow bolt. Gun has a 12 inch barrel. Velocity Adjuster was unscrewed all the way, so no extra tension on the spring. Also used one of Anthony's Protops to test the gun with 12 gram cartridges.

Temp 65 degrees using co2 12 gram
14.66 grain Beeman FTS domed
CED Millennium Chronograph

535
529
530
540
533
533
529
530
523
525
525
525
523
520
515
506

I will be testing again tomorrow when it is warmer. I also replaced the stock stem with a polished ground down one. I haven't started porting the valve, and I am over 9 ft/lbs for at least 1 shot.

I'd suggest lightening the striker a bit and trying a 1377 striker spring. Are you using a harder stem, like a Disco or home made nylon 66? If not there's some free power to be gained by using one and quickening the valve response.
Keep up the good work.
Anthony

With stock valve stem, stock weight valve spring, and stock weight hammer spring. Valve has no porting or polishing. The breech is Cothran Machine with hollow bolt. Gun has a 12 inch barrel. Velocity Adjuster was unscrewed all the way, so no extra tension on the spring. Also used one of Anthony's Protops to test the gun with 12 gram cartridges.

Temp 65 degrees using co2 12 gram
14.66 grain Beeman FTS domed
CED Millennium Chronograph

535
529
530
540
533
533
529
530
523
525
525
525
523
520
515
506

I will be testing again tomorrow when it is warmer. I also replaced the stock stem with a polished ground down one. I haven't started porting the valve, and I am over 9 ft/lbs for at least 1 shot.

A VERY effective upgrade we hope you perfect and would like to have a couple myself.

Thanks for all the effort your making.

Be Well... Tom

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