Benjamin 397P Phase 1

[--ped--]

the robber one is but the o ring head does work and work well,it just needs the valve front making with a flat face like the one in the pic i put up earlier in the thread
with you not constrained by a power limit Louis a scratch built piston without the blow off would make sense

[ratbuster2240]

Hi Louis, I'm really excited about this Innova, like a Benjamin/Sheridan but has a much better way of scoping and moderating.

I see the alloy breeches like fitting the Crosman aftermarket steel breeches on the 22 series.

I'm also not sure about the oring type piston seal, they tend to damage easily. This one was nicked when I removed it and I've ordered some heavy duty ones to try. The first thing I did to the tube before blueing was sand inside the cylinder with fine grit wet and dry, to remove any burs. The burs are especially bad around the pivot point holes.

As ped says I also think the two mating surfaces of the piston and valve are mismatched when fitting the trobb head. This could caus increased head space and a rubbish seal.

I will see how It goes but I may have to do as you've done and fit a good quality pump cup.

Wow, that Innova is going to be super nice.
I must admit that I like to keep things original, but I understand that this gun will probably live longer than my ones with the plastic parts still in place.
The TR Robb pump head: please bin it. Now. LOL. I spent so much time, energy and money on trying to get mine to work well. Totally useless imo. A pump cup is the way to go in an Innova.

[--ped--]

burrs on the pin hole and the slot need removing before fitting an o ring piston
i find that the 90 shore rings are too hard and whilst i'll use a quad seal on the valve i'll not use one on the piston
i use a hnbr 70 on my 13xx FTP kits dearer than nbr but a lot more heat resistant
you'll also find over lubing using an oil that has detergents in will degrade the o rings use hydraulic oils or the green oil i sell

[ratbuster2240]

I usually find thick bearing type grease, 3 in 1 oil and WD40. Clearing it all out and using the proper green hydraulic oil, keeps the internals clean and free from oxidation and makes pumping a lot smoother.

[ratbuster2240]

Tonight was a bit cooler so I didn't mind pumping up the Benjamin 342 for a short session.

The old Multi pumps like the heavier pellets and the 18.13gr JSB jumbo's perform well.

[--ped--]

i'll try to get you that insert in the post mon, you might have to adj spring a bit so i've not closed and ground the spring

[ratbuster2240]

Thanks Ped

I'll play around with the spring. Is that heating it, compressing the end coil and quenching It?

i'll try to get you that insert in the post mon, you might have to adj spring a bit so i've not closed and ground the spring

[--ped--]

yes but i've found a different spring and ends are closed and will just need a grind flat if the tension is ok

[ratbuster2240]

Perfect! Thank you.

yes but i've found a different spring and ends are closed and will just need a grind flat if the tension is ok

[jirushi]

Last weekend I did some shooting with this .177" Mk1 Innova.
The 4x20 Mars scope is clear, but the crosshairs are blurry at my 29 meter range. I must reparallax it.

I used a MTM gun rest to test maximum accuracy. The rest makes it super easy to hold the gun dead still.
A 1 cm group at 29 meters with 4 pumps and 8.44 gr 4.53 mm JSB Exact. Happy days!

The original Sharp gun slip was sent to me by a Japanese friend in Tokyo.

[--ped--]

that's nice Louis

[ratbuster2240]

What a great way to spend an afternoon with a beer and target shooting from the comfort of your shed.

That's very impressive accuracy Louis, they are very capable pneumatics and that gun bag in brown and beige, you can't get anymore retro than that.

[MartynB]

A 1 cm group at 29 meters with 4 pumps and 8.44 gr 4.53 mm JSB Exact

If that was edge to edge then very good

[ratbuster2240]

I picked up this very clean Crosman 766 and a Jap Nikko scope from Purbeck guns at Kempton today, Brian is always a gentleman to deal with.

I gave the metal work a clean with some surplus MOD gun oil and and the plastic stock with some plastic and rubber care. The seals are in good condition and with good few drops of secret sauce, it was pumping with ease.

Model 766 American Classic Pneumatic, BB repeater, .177 cal., single shot. Second variant with tapered steel barrel housing. Rifle 1977-1981

[--ped--]

looks nice and clean