Sub minor

[Speedwagon]

Shooting the Area 6 Championship and get to the chrono stage and power factor comes to 121. I'm thinking to myself WTF! My loads is 3.2 grains of Titegroup with a 147 grain Berrys RN bullet. I chronoed them and got a power factor 130 with the lowest muzzle velocity of 20 rounds and I've shot many matches with this load and always made power factor. 

I loaded them in my basement at 70 degrees and when we got to the chrono stage it was about 45 degrees so I figure the temperature difference could be what made part of the difference, but not that much. I usually check my powder drop about every 20-30 rounds by calibrating my scale and rezeroing it. 

I still have some of the ammo left so I'm going to put some in the fridge and keep some warm to see just what the difference comes out to. I'm going to compare my chrono readings with a friends too but what really baffles me is that I've used this load at many other matches and never came close to having a problem at chrono. I need to find out what went wrong so this doesn't happen again!! 

I was able to shoot the rest of the match but my score didn't count. I had fun but still baffled anb disappointed with what happened. 

[BritinUSA]

Not sure what the chrono setup was at Area 6, if its a dual optical chrono setup then you should watch both and see how much of a variation they have shot to shot.

The optical chrono's are not terribly accurate, so I would suggest trying to make 132-135PF with your lowest velocity instead.

 

[Sinister4]

Well when I tested tightgroup with 124 gr 9mm it  dropped aprox 52 fps from 68F to 20 F   

[Speedwagon]

36 minutes ago, BritinUSA said:

Not sure what the chrono setup was at Area 6, if its a dual optical chrono setup then you should watch both and see how much of a variation they have shot to shot.

The optical chrono's are not terribly accurate, so I would suggest trying to make 132-135PF with your lowest velocity instead.

 

They were using a double optic. I did see a slight difference but at that time I was so dumbfounded and frustrated I didn't know what to think. I do know it was about 80 FPS lower than what I chronoed them at. 

I'm definitely going to bump my load up to closer to 135PF. Don't want this to happen again. Lesson learned.

[Speedwagon]

17 minutes ago, Sinister4 said:

Well when I tested tightgroup with 124 gr 9mm it  dropped aprox 52 fps from 68F to 20 F   

Good info, thanks. I'm going to do more comparison of different temps but I still want to find out what I did wrong to make the whole difference. 

[Sinister4]

Just now, Speedwagon said:

Good info, thanks. I'm going to do more comparison of different temps but I still want to find out what I did wrong to make the whole difference. 

I was testing a load for a 9mm with a comp that had trouble cycling at the outdoor temp so I cooled both ammo and gun to 20 for the test, 2 different chronos both same basic results speed wise

[BritinUSA]

TiteGroup is notorious for temperature sensitivity. I realize that you may not have much powder choice these days but I think Sport Pistol was more consistent with varying temperatures.

[Speedwagon]

2 minutes ago, BritinUSA said:

TiteGroup is notorious for temperature sensitivity. I realize that you may not have much powder choice these days but I think Sport Pistol was more consistent with varying temperatures.

I used to use Sport Pistol but I'm out of it and can't find any now.. I picked up some VV N320 this weekend and have some Cleanshot so I'll see what I get with those. Probably use Titegroup for local matches and whichever is more consistent for major matches. 

[Boomstick303]

58 minutes ago, BritinUSA said:

but I think Sport Pistol was more consistent with varying temperatures.

 

Not from my testing.  Lost 7-8 PF when chromed in Colorado at around 75 F which yielded a PF of about 135.   At PCC Nationals that dropped to 127 PF where the temps were in the mid 90s F.  

 

Good luck on finding any Sport Pistol Moving forward.  Rumor has it Federal is buying all of it up for their Syntech ammo line.  

Edited April 19, 2022 by Boomstick303

[BritinUSA]

I think I have a pound or two in my garage somewhere…

[Bdh821]

hmm, I'd think 3.2TG under a 147 would easily make 130pf.  Sorry to hear.  The chrono's at A6 seemed to be right on with my chrono from home.  I also chrono'ed in similar temp as A6 too tho.  My ammo seems to always chrono at 140pf in hot or cold.  I use Sport Pistol.. 

[Lightj75]

The chrono at A6 was right on my at home testing. I use N330 though and haven't ever noticed any differences in Temps from 30-80°. I'm betting the sensitivity of TG is the culprit. If you got some N320 I would go with that, coated 147gr FPs with 3.0-3.2gr @ 1.13 is usually what I load N320.  

[Speedwagon]

13 hours ago, Lightj75 said:

The chrono at A6 was right on my at home testing. I use N330 though and haven't ever noticed any differences in Temps from 30-80°. I'm betting the sensitivity of TG is the culprit. If you got some N320 I would go with that, coated 147gr FPs with 3.0-3.2gr @ 1.13 is usually what I load N320.  

Google info, I plan to explore this. Thanks 

[Skytrooper]

I chrono mine for minor for a PF of 135

Edited May 5, 2022 by Skytrooper

[davebenson]

When I question the validity of the PF at Chrono if they are using 2 optic chrnos I ask to see their log book of how they measured using the match calibration ammo.  If that looks okay validate they used the bullet weight to the tenth. That is 124.9 and not 124.  You use the tenths in weight but not bullet speed.   Velocity of 1122.7 is 1122.  
 

I have had to correct a couple chrno staffs on this when I noticed several folks not making PF. When recalculated they made PF. 
 

all in all review USPSA rules appendix C2 for how chrno should be managed. 
 

Match Chronograph Daily Verification
Chronograph(s):
17.
Prior to performing any competitor
ammunition testing, the Chrono Officer will
fire three rounds from the supply of the
official match calibration ammunition
through the calibration firearm over the
chronograph(s) and record the average
velocity of the three rounds for each
chronograph in use.
18.
Dual chronograph configurations are
not subject to subsequent daily verification
provided that the differential of the
velocities between the two chronographs
remains reasonably consistent with the
differential of the average velocities
recorded above.

 

if everything is up to speed at chrno then look at your velocity spread.  I reload range brass and can see big differences in velocity based on case manufacture even with hand measuring powder.