Shooter App and velocities seem off?

[Freediver111]

Found a great load for my 6.5 CM after some testing and hit the range with it yesterday.
Lapua brass, 47 gr. RL26, CCI450, annealed brass, .020" off the lands with ELD-X's.

Borrowed my buddies cheaper F1 chrono and took readings. 5 shots were all in the 2950 fps range and data looked awesome. I'm talking like 9 fps ES. Groups were fantastic. All 5 shots were touching.

So I'm stoked! But then I stretch it out on the 500 yd gong. Buddy spotting for me and calls it low. Come up a few clicks and bang. So I tell Shooter app that I need 2.6 mils up instead of 2.3 hat it originally told me. Tell the app to correct for MV, now it's saying I'm actually at 2780 or so fps. That can't be! WTF. So I have one round left (should have brought more ammo). Take it out to 1,000 and it's a little high at 7.8 clicks. Still hit the plate. So now I'm thinking the app is working using a velocity of around 2800 fps, when the F1 Chrono is pretty consistent at around 2950.

I'm confused. Obviously I need to spend a little more time dialing in, but my 100 yd zero was perfect. I'm using a 26" barrel and from everything I read, guys are consitenlty getting around 2900 fps with RL 26 out of the 6.5 Creed.

So what the heck? Should I invest in a Magnetospeed and test some more? Obviously I need to hit the range and get more hits out to 1,000 to confirm the data, but it seems like the app is working well using a MV of around 2800 fps, which just seems strange.

Thoughts? I realize this is more of a random thought kind of thread and confusion will remain until I get more range time at distance, so there is that.....and I realize I have no complaints with the app is it is getting me on target with the suggested clicks, so I'm not complaining about that. Just scratching my head at these velocity variations.

 

[spaniel]

Are you certain that you accurately inputted all of the other variables, environmental and otherwise, which go into the calculation?

 

[Freediver111]

Are you certain that you accurately inputted all of the other variables, environmental and otherwise, which go into the calculation?

Yup. Took my time and made sure.

 

[Freediver111]

Hit the range again today and confirmed my door at 1,000. I shot a 5 shot group that was sub MOA and the new velocity it gave me based on that data is 2850. That makes a lot more sense, but still weird it’s off 100 FPS from the chrono. I know it’s not the best chrono ever, but still not terrible. I made sure to set the chrono level and square too. Just seems odd, but my dope looks spot on so I guess that’s all that matters.

 

[powereng]

I wish I could help but I have the same issue with Shooter and my 308. My practice target is at 877 yards. Shooter says 8.6 mils, actual to hit is 9.2 mils using my Magnetospeed to confirm my input velocity of 2650fps. I have played with ever other variable in the app imaginable and I still can't get shooter to give me 9.2 mils.

 

[waveslayer]

Play with the BC of the bullet and see how it works out for you matching up with you DOPE... using the original velocity

 

[onevan]

My experience is: no playing with BC! Better to measure bullet drop between ballistic application and reality. Then use drop calibration which increase or decrease muzzle speed.

 

[morganlamprecht]

shoot 400-600 yds and adjust velocity

shoot 800+ and adjust BC to fine tune

adjusting velocity off of longer ranges will throw off your short/mid range dope...BC is variable between rifling, twist rate, bullet lot, conditions, etc, its not a set number...this all assumes your scope has a good zero, tracks true, and your target distances are spot on, any variance/error in these will throw in error, as well

 

[Freediver111]

So longer story, I did originally start by zeroing at 100, then moving to 500. At 500, the dope Shooter gave me was off, but not by much. At 500 using a G7 of .315 for the Hornady ELD-X 143's and a MV of 2950 it says 2.3 mils up, when in reality I need 2.5 Mils.

Then at 1,000 I found I need 7.6 mils rather than 7.0 it gave me using 2950 fps and the same .315 G7 BC. I confirmed this by making 5/5 hits at 1,000. Groups were excellent and perfectly in line with the center dot I was aiming at. I had three shots all hit within 4" of each other. It shot a little right, but elevation was perfect (wind being the factor I'm sure for the L/R variance).

Playing with the BC's I had to drop the G7 BC to .275 in order to get me to 7.6 mils at 1,000 and 2.4 at 500 using 2950-2940 fps. Those mil numbers align with field observations, although I dropped the BC significantly.

Using the BC listed at .315 G7 or .625 G1 and 2950-2940 fps tells me much more like 7.1 Mils at 1,000, which will end up making hits on dirt.

Something is weird here. I know from reading many peoples observations with RL 26, Lapua brass, and 143's out of a 26" barrel I should easily be in the 2900 fps range, and my chrono, while not high end, gave me 5 readings in the 2940-2950 fps range and ES of 9.

 

[Stpilot12]

The F1 chrony I had was a POS... You could try if a different chrono, but at the end of the day, don't put all your belief in the gizmo, go with the DOPE. As Lowlight says, believe the bullet, it doesn't lie

 

[Freediver111]

So longer story, I did originally start by zeroing at 100, then moving to 500. At 500, the dope Shooter gave me was off, but not by much. At 500 using a G7 of .315 for the Hornady ELD-X 143's and a MV of 2950 it says 2.3 mils up, when in reality I need 2.5 Mils.

Then at 1,000 I found I need 7.6 mils rather than 7.0 it gave me using 2950 fps and the same .315 G7 BC. I confirmed this by making 5/5 hits at 1,000. Groups were excellent and perfectly in line with the center dot I was aiming at. I had three shots all hit within 4" of each other. It shot a little right, but elevation was perfect (wind being the factor I'm sure for the L/R variance).

Playing with the BC's I had to drop the G7 BC to .275 in order to get me to 7.6 mils at 1,000 and 2.4 at 500 using 2950-2940 fps. Those mil numbers align with field observations, although I dropped the BC significantly.

Using the BC listed at .315 G7 or .625 G1 and 2950-2940 fps tells me much more like 7.1 Mils at 1,000, which will end up making hits on dirt.

Something is weird here. I know from reading many peoples observations with RL 26, Lapua brass, and 143's out of a 26" barrel I should easily be in the 2900 fps range, and my chrono, while not high end, gave me 5 readings in the 2940-2950 fps range and ES of 9.

Ranges were confirmed with my Leica 1600 and this is at a range, where plates are set from 300-1100 and RF readings verified they are correct distances.
Scope is a 10X SWFA, and I have no issues with tracking. It tracks true, holds zero, and equipment-wise all indicate that my scope/rifle are true.

 

[Freediver111]

I'm tempted to get a Magneto speed to confirm, but at the same time if my dope is coming out spot on using 2850 fps, not sure I need to go that route. I know the F1 is not the best, but I'm surprised it's off by 100 fps when readings were consistent. Using 47 grains of RL 26 and a 26" barrel, I expect to be around 2900 fps. My dope tells me I'm at 2850, and my F1 says 2950. Interesting results, but obviously I trust my current dope set to 2850 since I'm making hits and things are lining up nicely compared to when I used 2950.

 

[Stpilot12]

Run with the dope. The Magneto V3 is a good unit for sure.

I've not used RL 26, but 2900+ seems a little unrealistic with 26"/143eldx combo. (but I could be wrong) Im running H4350 and RL16 with 140eld and 147eld out of a DTA with 30" With 42.5gr H4350 the 140 is avg 2918fps and the 147 2898fps (thats a pretty stout load btw) with 42.5 gr of RL16 the 140 is doing 2958fps.

 

[morganlamprecht]

id ignore that chrono

 

[gebhardt02]

A Shooting Chrony F1? I used to have a Chrony, finally realized what a piece of junk it was after getting a Magnetospeed. The Chrony had about a 10% error in velocity, to the slow side.

Which scope do you have and have you done a very good tall target tracking test, 10 mils worth? I've had several different brands that don't track completely true to 10 mils. Currently have one from well known company that only needs 9.8 mils dialed to give 10 mils of impact change. It's entirely consistent and repeatable though so I can account for it.

To adjust for that in "Shooter" you can edit the impact correction. In my case, it changes from 1.0 to a 0.98 value. Now my velocity is accurate, BC numbers I trust from Litz, and my predicted value lines up with actual drop.

I'd highly suggest finding another chrono, Magnetospeed works very well for me.

 

[Freediver111]

I haven't done a tall target track test yet. Plan to, just haven't done it.

It's a fixed 10X SWFA SS scope. Seems to track true when sighting in, but as I said, haven't done a tall target test yet.

 

[gebhardt02]

I have two SWFA scopes, one is a fixed 20X and the other is the 3-15 F1. The 20X doesn't track true, it only requires 9.6 mils dialed to get 10 mils impact change. That one I use on my .22 LR and I really like it for that application. The 3-15 I've only had a week or two but a tracking test with it hard mounted on a stand indicates the reticle moves a full 10 mils with 10 mils on the turret. Actual tracking test will verify, but it has a good indication so far.

You might just have a tracking error in your scope combined with a small error in velocity.

 

[waveslayer]

I bet the scope is off via the tracking. The F1 is a piece and playing with the BC might help. BC is dependent of velocity, so it changes over the course of fire

 

[hereinaz]

I haven't done a tall target track test yet. Plan to, just haven't done it.

It's a fixed 10X SWFA SS scope. Seems to track true when sighting in, but as I said, haven't done a tall target test yet.

Given the drastic changes to velocity and BC, I bet you are not getting the right click value. If you do the math on that, I bet you might could find a correlation...

SWFA will go up and down, and return to zero, but click values is a harder thing.

Good shooting with a 10x.

 

[hereinaz]

Was it the turret tracking? Curious.

 

[jitter]

Chrony F1 gives pretty consistent result to assess load consistency but absolute numbers could be aside of truth but not much.
Need to check it by bullet drop.
I've got F1. Gives numbers almost true.

FYI
Chronograph Performance Review by Applied Ballistics, LLC
Chrony is not so bad.

http://www.appliedballisticsllc.com/Articles/ChronographChapter.pdf

 

[steve123]

It wasn't til I got a Oehler that I was able to diagnose the 3 crappy F1's my friends and I had, one was off more than 100 fps. Mysteriously our dope made sense for the first time.

You are way better off truing from known BC's with the ballistic app and changing FPS instead. The bullet is doing what it's doing, believe it, write down your drops at different distances and get the known drops lining up with the app the best you can. You do have the scope height correct and are using station pressure or DA at location, hopefully.

Play with the correction factors too, not even doing a tracking test on paper I've found some scopes were off. Only .15 mil on one scope by 7 mils but enough to notice.

 

[NewsShooter]

Believe the bullet over the chrono every time.