Barnes 2 years and a loss of 220FPS

[JRG go long]

**** FIRST TIME POST *****
I am having a issue with my confidence in Barnes ammo, 2 years ago I decided to use the Barnes TTSX 150g 7mm off the shelve for my long range bullet, I did the chronograph and came up with 3119 as a average and had turrets cut to match from Kenton industries. I took the gun out to make sure it was still zeroed and my chronograph speed was still on, and to my surprise it was not my average is now 2898 and I have less then 20 rounds through the gun between each test. Any help or recommendations would be awesome. I am in a crunch for time and may need to make a change or just order new turrets but I don't want to have to order new turrets each year because a MFG may have change the powder or charge weight they use.


"Sounds like a good discussion question for you to ask in the forums."
is what Len sent me so I am here

 

[Pdvdh]

Which brand and model chronograph did your collect your velocity data over?

 

[JRG go long]

Which brand and model chronograph did your collect your velocity data over?

The F-1 Shooting Chrony

 

[sambo3006]

You may not have gotten a good reading from your chronograph due to light conditions. They say the best conditions for the sensors are overcast, not direct sun light. If you have the chance, shoot your rifle at long range and if your drop is still consistent with your turret (and your baseline zero is still on) I wouldn't worry about the chronograph reading.

 

[JRG go long]

You may not have gotten a good reading from your chronograph due to light conditions. They say the best conditions for the sensors are overcast, not direct sun light. If you have the chance, shoot your rifle at long range and if your drop is still consistent with your turret (and your baseline zero is still on) I wouldn't worry about the chronograph reading.

I ran three different guns through the chronograph that session and this was the only one that was off from past load data. Also my 250 yard zero is off by three clicks

I have contacted Barnes and spoke to Ryan, he stated that they have not changed the powder or charge weight in the last year and a half

 

[Wedgy]

All the more reason to stay with MOA or Mil turrets and load your own ammo. I have a rifle that shoots .4 MOA with a particular ammo from Winchester. Suddenly it went to 4" groups. Finally figured out I got a bad box of ammo. I thought the barrel was shot out. I still haven't worked up a load for this gun because I found more "good" factory ammo, but I don't have the confidence in it that I had.

 

[elkaholic]

I ran three different guns through the chronograph that session and this was the only one that was off from past load data. Also my 250 yard zero is off by three clicks

I have contacted Barnes and spoke to Ryan, he stated that they have not changed the powder or charge weight in the last year and a half

Could your first box of ammo been produced BEFORE that 1 1/2 year date? I would ask them what, if any changes were made prior?.....Rich

 

[ericbc7]

You may be stuck with buying another turret since factory ammo performance can vary from lot to lot. If you do go to the expense of a new turret, I suggest you buy a case or two of the ammo with which you calibrated the turret (making sure it's all from the same production lot). If it's stored well, I would guess that older ammunition from the same lot will perform more similarly than ammo from different production runs.

you may be able to find a current batch of ammo, perhaps from a different manufacturer or component combination, that will shoot reasonably close to your existing turret for this season so you won't have to scramble to put everything together at the last minute.

Good luck!

 

[coyotezapper]

All the more reason to stay with MOA or Mil turrets


+1 Then all you have to do is verify new drops. Easy to do.

 

[Garycrow]

Factory ammo will almost never give the same speed or shoot to the same POI from lot to lot. If you're dead set on using factory ammo and having a turret custom made for it then you need to buy enough of that lot of ammo to last you for your hunting career. I've seen 200+ fps variations out of different lots of the same ammo several times. Factory ammo just isn't consistent. People assume it is but the easy availability of chronographs tells the tale.

It's one of the main reasons all precision shooters handload.

 

[Bosshog]

You may not have gotten a good reading from your chronograph due to light conditions. They say the best conditions for the sensors are overcast, not direct sun light. If you have the chance, shoot your rifle at long range and if your drop is still consistent with your turret (and your baseline zero is still on) I wouldn't worry about the chronograph reading.

I have seen 200 to 300 fps difference in the same load during different shooting sessions using the exact same load and chronograph. The only conclusion I have come up with is that it was due to different lighting conditions and the sensitivity of optical chronographs. I have since started verifying velocity with a Magneto Speed.

 

[Lefty7mmstw]

I have seen 200 to 300 fps difference in the same load during different shooting sessions using the exact same load and chronograph. The only conclusion I have come up with is that it was due to different lighting conditions and the sensitivity of optical chronographs. I have since started verifying velocity with a Magneto Speed.

get a m35 oehler, it will tell you if it's lying to you and it doesn't hang on the end of the barrel, screwing up or moving your groups. I see the Labradar as a good option (a bit spendier though) but not sure how an acoustical trigger will work on a busy range.

to the o.p.,
As to factory ammo, they will have at least a few powders that will "make spec" and they will switch between the powders based on availability, etc. They haven't changed anything, but it may have not stayed the same either. Your rifle just behaves differently depending on powder even though they are both spec..

 

[Beng]

Custom turrets are worthless anyway. Your trajectory varies with air temperature and altitude due to changes in the density of the air. Custom turrets are only correct for one muzzle velocity at one temperature and altitude, they are off nearly everywhere else. Don't throw good money after bad, get a mil dot reticule and ballistic calculator.