Changes in velocity

[Pwhite11798]

Today I was testing some loads using the ocw method. In every on of my string I had 1 or two rounds that had excesive increase in velocity causing vertical. As I wrapped up my shooting session I noticed that the cases that shot faster had no gun powder residue around the inside or outside of the case necks. And after looking at my crono data it correlates exactly with the spread in velocity and the group dispersion on my target. Below I included two picture to help understand what I am talking about.

 

[Pwhite11798]

 

[Pwhite11798]

 

[Pwhite11798]

Does any body know what would cause this to happen while reloading

 

[dedogs]

Need more information on the brass(history) and the loads. dedogs

 

[Pwhite11798]

Loads were : lapua Palma brass, barnes 175 gr match burners. Sellier and bellot sr primers. Power pro 2000 46 gr, 46.4gr, 47.2gr, 47.6gr, 48gr

 

[Zero333]

Change primers.

CCI450 or CCIbr4 or 205/205m

 

[fastarget]

hot chamber?

 

[XTR]

Loads were :Power pro 2000

It's not the brass.

Look around; I've posted about this before. I tried PP2000 for F-TR a few yrs ago, after one particularly frustrating state championship match I went home chrono'ed some 10 shot strings. I could get fantastic ES 80% of the time, but 10% to 20% of of the shots would be as much as 80FPS faster than the mean.

Result = some high to very high 9s, followed extreme frustration caused by the low ones I got after I dialed.

Get a different powder.

 

[Pwhite11798]

It's not the brass.

Look around; I've posted about this before. I tried PP2000 for F-TR a few yrs ago, after one particularly frustrating state championship match I went home chrono'ed some 10 shot strings. I could get fantastic ES 80% of the time, but 10% to 20% of of the shots would be as much as 80FPS faster than the mean.

Result = some high to very high 9s, followed extreme frustration caused by the low ones I got after I dialed.

Get a different powder.

Sounds exactly what I am experiencing.

 

[Pwhite11798]

hot chamber?

No wasn't baking the rounds and I shot slow for load development.

 

[X-Caveman]

There's a kick in the nuts. 9lbs of PP 2000-MR on the truck headed my direction. Gonna pretend I didn't see this... Or possibly end up loading 2,600 rounds of .223 plinking ammo...

 

[Pwhite11798]

It's not bad powder it's just not long range powder for comps. You will get good loads out of it.