When does velocity not equate to pressure?

[AZDAVE]

Your crono gave you a bad reading. My shooting buddy and myself both have the same model and they give great results, but having said that I have had mine give me some questionable reading. When ever I get something that looks just blatantly wrong I cross check with my buddies to make sure it wasn't just off on a coffee break. Having tried most all powders suitable for the 9.3 RL-17a and Ramshot Big Game are the two best powder for good velocity at the lowest pressure. CFE 223 has been reported to also give good results but I haven't tried it as I have developed solid loads from 250-320gr bullets with the two powders I mentioned.

I would recheck your crono and shoot at least 10 rounds over it, to get a better baseline.

 

[ChrisG]

Yeah it sounds like a bum chrono reading.

Velocity equates to work done by the powder, not pressure. 3,500psi will push a 286 grain bullet to mach 3 if you have a long enough barrel and the pressurized gas didn't weigh anything or cost anything to move. But no way are you getting enough extra work from a powder to get 1000fps extra. The other thing you should note is that 1000 extra FPS would add (1000*(286/7000)) lbf*s to the momentum of the rifle which would amount to a whole lot of extra recoil.

 

[sgt_zim]

my recent trials with 285 gr Norma Oryx and 2000MR (starting at 58.5 gr) went much the same way. 5 shots, about 3350, about .7 MOA. Packed up all my crap, went back to the cabin, had a brewsky myself.

Curious - I found "Gordeon's Reloading Tool" and have been playing around with it. Have you (or anyone here, for that matter) ever tinkered with it, and if so, how accurate did you find it to be?

holy crap, that should have been 2350

 

[sgt_zim]

That's what I get for posting from my phone instead of my laptop. SMDH

 

[shootist~]

That's what I get for posting from my phone instead of my laptop. SMDH

No worries. It was assumed you were citing an example of a whacky chronograph reading.