Diana Model 6 power

[Anchorman]

Hello
I have a 1972 Diana Mod 6 pistol which I bought off this forum in 2011. It had been fitted with synthetic seals in 2010 by a well respected member who included photos of the strip and rebuild. Its been great and have used 2000 pellets. Just lately the power seems to have dropped and it is now reading 2 ft. lbs. using Hobby sports Line pellets 7 grain. Never chrono it before What is the acceptable power for this type of recoiless pistol please
Many Thanks
Dave

[Benelli B76]

2.5 to 3.2 ft lb.

Baz

[Geezer]

2.5 to 3.2 ft lb.

Baz

That. They were always listed at max 450 fps, which, with the 7grn match pellets of the day is a tad under 3.2.

It may be down to the ravages of time, or quality of rebuilds, but I’ve seen recent chrono tests varying from 3.2 or a tiny bit higher down to as low as 2 and a bit. But ending up on 2 having been higher suggests that something is amiss inside.

[Anchorman]

Thank you both for your replies. I will investigate further.
Dave

[Shed tuner]

I recently bought a giss pistol. It shot fairly well, but cocking didn't feel that smooth. I removed the two cog caps, and splurged in a gob of moly to each, getting it on the cog itself and the rear rack of the pistons. Put it back together, a couple of shots later I chrono'd it and it gained 30 fps and was much smoother to cock. Might be worth a try, but remember those caps are indexed so don't switch them around.

[Benelli B76]

I bought one a few months ago for 40 quid, nice condition but only doing 250 fps with 7 grn pellet. Thought the polyurethane piston seal had gone crumbly. Stripped it down and someone had already fitted a new one. What they had done was assemble it and had the two side gears out of position by one or two teeth. When I re-assembled it correctly fps increased by almost 200. Now shoots like a dream, smooth and accurate as they do in correct condition.

Baz