Diana 34 Chrono Test

[outdoorman]

Anyone have Chrono numbers from their Diana 34? I was pleasantly suprised to find my Diana 34, with over 4000 pellets through it, is shooting 14.2gr .22 pellets at an average of 748fps. That's 17.65fpe. I'm impressed. My new Crosman Nitro Venom is shooting the same pellets at an average of 715fps. I do have the Vortek PG2 spring in the Diana. Don't know what the numbers are for the stock spring. From what I have been reading online, I expected the Diana to be around 700fps.

 

[Guest]

"outdoorman"Anyone have Chrono numbers from their Diana 34? I was pleasantly suprised to find my Diana 34, with over 4000 pellets through it, is shooting 14.2gr .22 pellets at an average of 748fps. That's 17.65fpe. I'm impressed. My new Crosman Nitro Venom is shooting the same pellets at an average of 715fps. I do have the Vortek PG2 spring in the Diana. Don't know what the numbers are for the stock spring. From what I have been reading online, I expected the Diana to be around 700fps.

That is very high for that power plant. Most Model 34s are shooting around 14 fpe. My .177 shoots around 860 fps for just over 14 fpe with H&N FTT. Most of the other people I've talked with who own that power plant are seeing more or less the same thing.

 

[outdoorman]

It does seem a little high but I did read where another airgunner was getting mid 700's with the Vortek spring. Dieseling may be a little on the high side? I don't know. It is certainly not detonating so I'm not too concerned.

 

[MDiver]

I have a 36 (same as 34 and 38) in .177 shooting at 13.6 fpe with a Konceptus kit. I could possibly squeeze another fpe but it would make it too harsh.

 

[outdoorman]

Did some more chrono testing today and did find out that seating the pellets reduces velocity significantly. I use a pellet pen to load pellets and the other end of the pen can be used for seating the pellet. I do this to prevent any deformation of the pellet skirt upon closing the barrel. The seating is adjustable and I now have it set to absolute minimum to prevent deformation. If I seat the pellet into the barrel just a millimeter or two, it reduces the velocity by 30fps. By seating too much, you are effectively increasing the size of the combustion chamber and thus reducing maximum pressure. I had heard of this before and can now confirm by my own testing.

 

[crosman2016]

Well, with the quality of the Diana, after 4,000 pellets, I am not surprised to see that kind of chrony results.

 

[Guest]

"outdoorman"Did some more chrono testing today and did find out that seating the pellets reduces velocity significantly. I use a pellet pen to load pellets and the other end of the pen can be used for seating the pellet. I do this to prevent any deformation of the pellet skirt upon closing the barrel. The seating is adjustable and I now have it set to absolute minimum to prevent deformation. If I seat the pellet into the barrel just a millimeter or two, it reduces the velocity by 30fps. By seating too much, you are effectively increasing the size of the combustion chamber and thus reducing maximum pressure. I had heard of this before and can now confirm by my own testing.

Increasing the size of the chamber probably. Definitely decreasing the resistance of the pellet being forced into the rifling. This is where the pressure (therefore heat and performance) difference really occurs.