Why would my velocity go up in free recoil?

[LCazador]

Got the same result a month ago. Huge extreme spread and higher velocity although not as big a difference. At the time I chalked it up to imprecise weighing as I was using a cheap scale at the range. However this time I loaded these to the kernel with a sartorius so I know the charges were consistent. Doesn't matter too much as my free recoil groups are consistently worse than shouldered. Just curious as to what's going on.

I'd say the load is at max or past max. While some maximum loads may flat line other loads may have erratic behavior with much higher velocity and big spreads at times. Measure head diameter of new cases and then monitor expansion to verify any excess pressure.

 

[WyleWD]

I make sure to keep my ammo in the shade. The gun was at its hottest as it was the last group I fired but I'd only done 25 rounds over a half hour or so and it's got a straight 1.25" barrel so it wasn't too hot.

25 rounds in 30 minutes is probably more than a bit on the hot side ..... at least it would be for my rifles. We might do 5-10 rounds in a half hour depending upon outdoor temperature and caliber and barrel contour. JME. WD

 

[Falfan2017]

25 rounds in 30 minutes is probably more than a bit on the hot side ..... at least it would be for my rifles. We might do 5-10 rounds in a half hour depending upon outdoor temperature and caliber and barrel contour. JME. WD

It's a 28" full contoured barrel. I don't even see much affect from the heat shooting strings of 20 rounds plus sighters 3 times for f class.

 

[Bkluke]

I make sure to keep my ammo in the shade. The gun was at its hottest as it was the last group I fired but I'd only done 25 rounds over a half hour or so and it's got a straight 1.25" barrel so it wasn't too hot.

Did your point of impact change as the velocity increased? If not, I would suspect your chronograph

 

[Falfan2017]

Did your point of impact change as the velocity increased? If not, I would suspect your chronograph

No it impacted the same. But it was only 200 yards. I'm suspecting the chrono seems unlikely the speeds could jump that much.

 

[Gilbert Garza]

I’m going to say that your freecoil is influencing your rifle in a way that it’s getting closer or further away from your sensor area on your chrony causing the error. That is way to fast and I’d take it as an error. When I run my magnetospeed I get roughly the same variance as Mr Wheeler stated of Mousel. The machines have a .1% variance that it would allow a couple FPS here and there. But having a swing that large would mean either your ammo cooked in your chamber, very hot chamber, or your chrony Misread the bullets path.