Oddball velocity causing ES to be high

[savageshooter86]

So dusing testing in getting 2 or 3 odd velocities that ruin ES. Out of 20+ rds testing Powder charges I had 3 odd ones. Today testing seating depth I had same thing. Brass is virgin. Barrel has 52 rds down it now. And at 500 yards today the odd balls out where the ones in group that were off.

284 win
Turned Norma brass
H4350
BR2
180 hybrids
9 twist barrel

This a primer, Powder not liked in this combo, or combo? Should I try different bushing?

Or might this be virgin brass inconsistencies?

Racking my brain.

 

[Terry]

I had a similar problem. I'm looking first at my powder charges.

 

[Lapua40X]

I'm working with

284 win
Turned Win. brass
H4831SC
BR2
180 hybrids
9 twist barrel

How "odd" are the velocities. It's rare but I have had similar problems. I usually throw out the few odd ball extreme velocities in a data set of 20 and rely on the median and work from that.

 

[savageshooter86]

I had a similar problem. I'm looking first at my powder charges.

I weigh every charge to the single kernel. so I know it's not different charge than others in the group.

I'm working with

284 win
Turned Win. brass
H4831SC
BR2
180 hybrids
9 twist barrel

How "odd" are the velocities. It's rare but I have had similar problems. I usually throw out the few odd ball extreme velocities in a data set of 20 and rely on the median and work from that.

Seems about 20 fps. others on group are within 3 to 4 fps then the "odd" one. And it's Labradar. So pretty surethane that's not it.

 

[ShootDots]

Once you get all the brass with a firing on them>>>>anneal the brass, prep it your normal way, use a Q-Tip to swab a bit of Imperial Dry Neck Lube in the neck prior to charging the case and seating the bullet. I would bet that you eliminate any "out-liers"..

 

[fredhorace77]

Seems like at one time I read on here that the seating depth and or seating pressure applied when seating your primer can cause a similar situation. I don't know how you are seating primers or what tool you are using but you might check and make sure you are not crushing the primer anvil area.

 

[savageshooter86]

21st century priming tool. Seat until I feel primer touch then barely squeeze handle from that point.

Ben- thanks for the tip

 

[dskogman]

I had the same issues but with H4831SC. As Ben said, shoot it once first and then see. Also I didn't have enough neck clearance which caused all kinds of weird issues. It has thick necks.

 

[Terry]

I weigh my powder charges to the kernel as well.

What else causes 20 fps variance?

 

[savagedasher]

I weigh my powder charges to the kernel as well.

What else causes 20 fps variance?

Primers and internal case difference . Larry

 

[RonAKA]

Or might this be virgin brass inconsistencies?

Sounds like you are using a bushing die. Have you run an expander ball through the neck of the new brass to ensure the ID is smooth and uniform? Use a lubricant like powdered graphite on the ID? Checked and removed the punching flash on the primer hole? Is the headspace consistent on the new unfired brass? It is hard to make cases longer without firing them. There are some inherent issues with unfired brass that can only be correct by firing them. My thoughts are to jam the bullets on the first firing to try and ensure uniform case position in the chamber and forming.

 

[savageshooter86]

It's odd to me that it occurred during powder testing then again in seating testing. Only couple odd ones during session. Almost have good enough load to take to 600 yard match and fireform the rest of my brass. Then maybe I'll see something or start narrowing it down to help eliminate it.

Several charges and seating depths would have single digits ES but then comes the oddball. All good info here. It's showing promise but the random 20+fps surely could cause flyers at distance

 

[dkhunt14]

Several charges and seating depths would have single digits ES but then comes the oddball. All good info here. It's showing promise but the random 20+fps surely could cause flyers at distance

It might not. I never worry about chrono readings. Some of my best groups are not with the best chrono results. I am talking 1000 yard groups. I use to set up the chrono and test a lot at 1000 and the results on the chrono didn't match where the bullets went.

Some of my best groups have been Fireforming at 1000 yards. Both with the 300 WSM and with a 308 Baer which was moving the case from a Weatherby to convention shoulder. That is a lot of movement. But I always shoot with the bullet in the lands. I have fired lots of 4 and 5 inch 10 shot groups at 1000 while forming. On the 308 Baer the groups were shot with 20 to 25 feet ES. Matt

 

[rardoin]

I have noticed something similar...a velocity outlier every now and then. I shoot cases converted from .308 Palma brass so a bit of working the brass during the forming process but after 3 firings I still had outliers...typically 18-22 fps faster. (I weight to he kernel on a Sartorius, use Wolf SR primers, anneal each firing, dry lube necks before seating...very consistent techniques also) What I have noticed is the few cases that were high velocity outliers had a little resistance to bolt closure compared to the other loads. I size the shoulder back 0.001" with a Warner die so I have little room for error. I brought this issue up with my gunsmith and he noted that he will get some brass that behaves differently, regardless of treatment, and will never base size exactly like the rest; he suggested 'pitching' those cases. At a match the next weekend, I substituted any round (5/70) that felt resistance on bolt closure with another that felt 'normal' and will discard those as I usually get a couple of 8' rings from elevation and at this match I did not. All my point drops were close 9's and I had better vertical than before. Perhaps your issue is similar?

 

[savagedasher]

I have noticed something similar...a velocity outlier every now and then. I shoot cases converted from .308 Palma brass so a bit of working the brass during the forming process but after 3 firings I still had outliers...typically 18-22 fps faster. (I weight to he kernel on a Sartorius, use Wolf SR primers, anneal each firing, dry lube necks before seating...very consistent techniques also) What I have noticed is the few cases that were high velocity outliers had a little resistance to bolt closure compared to the other loads. I size the shoulder back 0.001" with a Warner die so I have little room for error. I brought this issue up with my gunsmith and he noted that he will get some brass that behaves differently, regardless of treatment, and will never base size exactly like the rest; he suggested 'pitching' those cases. At a match the next weekend, I substituted any round (5/70) that felt resistance on bolt closure with another that felt 'normal' and will discard those as I usually get a couple of 8' rings from elevation and at this match I did not. All my point drops were close 9's and I had better vertical than before. Perhaps your issue is similar?

You don't think it could be from putting the same amout of powder in different capacity cases Not a chance that would happen . Larry

 

[dkhunt14]

I have noticed something similar...a velocity outlier every now and then. I shoot cases converted from .308 Palma brass so a bit of working the brass during the forming process but after 3 firings I still had outliers...typically 18-22 fps faster. (I weight to he kernel on a Sartorius, use Wolf SR primers, anneal each firing, dry lube necks before seating...very consistent techniques also) What I have noticed is the few cases that were high velocity outliers had a little resistance to bolt closure compared to the other loads. I size the shoulder back 0.001" with a Warner die so I have little room for error. I brought this issue up with my gunsmith and he noted that he will get some brass that behaves differently, regardless of treatment, and will never base size exactly like the rest; he suggested 'pitching' those cases. At a match the next weekend, I substituted any round (5/70) that felt resistance on bolt closure with another that felt 'normal' and will discard those as I usually get a couple of 8' rings from elevation and at this match I did not. All my point drops were close 9's and I had better vertical than before. Perhaps your issue is similar?

On a Dasher I only bump .001 of . 002 because of a chance for a blanked primer. On my WSM I bump .005. I don't like tight cases because they cause fliers at 1000 yards. Matt

 

[ShootDots]

I have noticed something similar...a velocity outlier every now and then. I shoot cases converted from .308 Palma brass so a bit of working the brass during the forming process but after 3 firings I still had outliers...typically 18-22 fps faster. (I weight to he kernel on a Sartorius, use Wolf SR primers, anneal each firing, dry lube necks before seating...very consistent techniques also) What I have noticed is the few cases that were high velocity outliers had a little resistance to bolt closure compared to the other loads. I size the shoulder back 0.001" with a Warner die so I have little room for error. I brought this issue up with my gunsmith and he noted that he will get some brass that behaves differently, regardless of treatment, and will never base size exactly like the rest; he suggested 'pitching' those cases. At a match the next weekend, I substituted any round (5/70) that felt resistance on bolt closure with another that felt 'normal' and will discard those as I usually get a couple of 8' rings from elevation and at this match I did not. All my point drops were close 9's and I had better vertical than before. Perhaps your issue is similar?

May I suggest something? If I were you, I would bump those shoulders back 2.5-3.0K so you get a bit more room in there. If you are running at or near the top of a max load, you will need that extra bit of room and you may very well not get cases that "stay stretched" and enter the chamber area with a degree of difficulty from the rest of your brass.

 

[RonAKA]

I brought this issue up with my gunsmith and he noted that he will get some brass that behaves differently, regardless of treatment, and will never base size exactly like the rest; he suggested 'pitching' those cases.

I tried that method. Problem was solved when I had no brass left to shoot!

 

[rardoin]

May I suggest something? If I were you, I would bump those shoulders back 2.5-3.0K so you get a bit more room in there. If you are running at or near the top of a max load, you will need that extra bit of room and you may very well not get cases that "stay stretched" and enter the chamber area with a degree of difficulty from the rest of your brass.

Ben, I intend to do that before next firing. I set this new barrel on the tighter end of tolerances and my usual bump in the last chamber is a bit low. I plan on pulling a 0.001" shim out on next sizing and see what happens. Thanks for the advice.

 

[JBO]

Once you get all the brass with a firing on them>>>>anneal the brass, prep it your normal way, use a Q-Tip to swab a bit of Imperial Dry Neck Lube in the neck prior to charging the case and seating the bullet. I would bet that you eliminate any "out-liers"..

+1