Range Report Truing only MV sufficient?

[Helislacker]

Hi there ,

I shot my Tikka 6.5CM at 413, 574, and 755 yards respectively. The trued muzzle velocity gave me 2603FPS and this was then reconfirmed with a center punch on a 10” plate at 574 yards followed by two near center impacts at 755 yards. With this info, I also shot a 6” plate at 413 yards, center punching it multiple times to ensure the trajectory at close range was accurate. I feel quite satisfied with the current MV, but I’m concerned that I haven’t trued it correctly because I haven’t shot out far enough and corrected the BC. I plan on shooting out to 1000, that’s about it, and I’m wondering if this trajectory validation is actually going to work out to that range just by truing MV. I don’t want to show up at a match and realize my ballistic data is only accurate within a certain window within the 100-1000 yard range. What do you guys think? Am I good to go? Or do I need to get this tuned up a bit?

Thank you

Zach

 

[_Windrider_]

Jesus that’s slow for a 6.5. What ammo you shooting? 140’s or 147’s? And what did your MV start at before you tweaked it

 

[Helislacker]

Jesus that’s slow for a 6.5. What ammo you shooting? 140’s or 147’s? And what did your MV start at before you tweaked it

From what I understand this is very common for factory Tikka barrels. I’m shooting 140’s. I had just been using the factory 2710 MV on the box.

I then downloaded StrelokPro pro which showed it was 2734 FPS for this bullet considering 5.8MRADS @ 755yds. I used this MV for a bit and quickly figured out it was completely wrong. Downloaded BallistocsArc and the Hornady App and began playing around, eventually finding that 2603fps was the recommended MV based on my trajectory on both of those apps. Turned out this was a very accurate number and led to good hits from 400-800. Not sure what was going on with StrelokPro.

 

[Deleted member 113831]

From what I understand this is very common for factory Tikka barrels. I’m shooting 140’s. I had just been using the factory 2710 MV on the box.

I then downloaded StrelokPro pro which showed it was 2734 FPS for this bullet considering 5.8MRADS @ 755yds. I used this MV for a bit and quickly figured out it was completely wrong. Downloaded BallistocsArc and the Hornady App and began playing around, eventually finding that 2603fps was the recommended MV based on my trajectory on both of those apps. Turned out this was a very accurate number and led to good hits from 400-800. Not sure what was going on with StrelokPro.

Easy, you used the wrong drag model. You put your G1 BC in the G7 drag model. That's why your speed is so slow when it lined up.

 

[Lunchbox27]

From what I understand this is very common for factory Tikka barrels. I’m shooting 140’s. I had just been using the factory 2710 MV on the box.

Very common, indeed. My 20" factory Tikka 6.5 barrel was 2565 for American Gunner and right around 2600 for the ELD-M. Stupid slow, stupid accurate!

 

[Helislacker]

From what I understand this is very common for factory Tikka barrels.

Very common, indeed. My 20" factory Tikka 6.5 barrel was 2565 for American Gunner and right around 2600 for the ELD-M. Stupid slow, stupid accurate!

what kind of barrel life did you get out your Tikka barrel? I’m expecting around 4000 moving at this speed. Is that about accurate?

 

[Helislacker]

Easy, you used the wrong drag model. You put your G1 BC in the G7 drag model. That's why your speed is so slow when it lined up.

I just checked it and I’m running 0.326 for a g7, which is correct. I really don’t know where Strelok is going wrong.

 

[Lunchbox27]

what kind of barrel life did you get out your Tikka barrel? I’m expecting around 4000 moving at this speed. Is that about accurate?

No clue. I had my smith spin a Proof Stainless on it at 600ish count. I wouldn’t doubt close to 3k

 

[Deleted member 113831]

I just checked it and I’m running 0.326 for a g7, which is correct. I really don’t know where Strelok is going wrong.

You have an input wrong somewhere. I'm running Strelok Pro, Trasol, AB, and Ballistic Arc.

All say 5.9 mils using 2600 fps, .327 G7, at 755 yds @2000 ft elevation.

 

[Billiam1211]

Question on true-ing data:

I have a Tikka in 6.5 Creedmoor and I replaced the factory barrel with a 26-inch Patriot Valley Arms prefit. Accuracy is great, however when I put my data into JBM or Ballistic AE I'm missing shots at matches due to elevation.

My load is 140gr ELDs w/ 42gr H4350 210M in Hornady brass. Avg Velocity is 2797 fps and SD is 10.

At 489 yards I was missing a 10-inch square by about 1/2 Minute over the top. At 605 yards it was the same. At 720 yards I was about a full minute over the top.

While at the match I increased the velocity on Ballistic AE to 2840fps, and the rest of the match I seemed to be right on, however I don't understand where my disconnect is. Any insight would be appreciated.

 

[Deleted member 113831]

Question on true-ing data:

I have a Tikka in 6.5 Creedmoor and I replaced the factory barrel with a 26-inch Patriot Valley Arms prefit. Accuracy is great, however when I put my data into JBM or Ballistic AE I'm missing shots at matches due to elevation.

My load is 140gr ELDs w/ 42gr H4350 210M in Hornady brass. Avg Velocity is 2797 fps and SD is 10.

At 489 yards I was missing a 10-inch square by about 1/2 Minute over the top. At 605 yards it was the same. At 720 yards I was about a full minute over the top.

While at the match I increased the velocity on Ballistic AE to 2840fps, and the rest of the match I seemed to be right on, however I don't understand where my disconnect is. Any insight would be appreciated.

Could be a number of things. Did you verify zero under current conditions?

 

[Billiam1211]

Could be a number of things. Did you verify zero under current conditions?

This was my zero check aiming at the top left corner or the square before the match. Also There was a KYL rack at 340yards and I was center punching all targets except the last 1, which I missed ?. My elevation misses were only at 450 and out.

 

[Deleted member 113831]

This was my zero check aiming at the top left corner or the square before the match. Also There was a KYL rack at 340yards and I was center punching all targets except the last 1, which I missed ?. My elevation misses were only at 450 and out.

What were the lighting conditions at zeroing vs later when shooting the farther targets?

 

[Billiam1211]

What were the lighting conditions at zeroing vs later when shooting the farther targets?

Funny that you ask, it was a lowlight night match. Targets all had up lighting on them so we could pretty clearly see them. Wind was very mild to none.

 

[Deleted member 113831]

Funny that you ask, it was a lowlight night match. Targets all had up lighting on them so we could pretty clearly see them. Wind was very mild to none.

So you zerod in daylight and shot further targets at night?

If so, my vote would be the change in lighting. If you zero in strong sunlight and then shoot when a cloud blocks out the sun, your rounds will go .3 to .5 high depending on exact conditions.

Light can, and often does, have more effect than any other environmental change.

 

[Billiam1211]

So you zerod in daylight and shot further targets at night?

If so, my vote would be the change in lighting. If you zero in strong sunlight and then shoot when a cloud blocks out the sun, your rounds will go .3 to .5 high depending on exact conditions.

Light can, and often does, have more effect than any other environmental change.

Thanks for the nugget! I was going nuts thinking my DOPE was way off yesterday. I've never heard of light having such an impact on POI. I'm going to make a separate card and compare performance next time I shoot a match. Guess the only solid way to learn this is through experience in the field.

 

[seansmd]

Question on true-ing data:

I have a Tikka in 6.5 Creedmoor and I replaced the factory barrel with a 26-inch Patriot Valley Arms prefit. Accuracy is great, however when I put my data into JBM or Ballistic AE I'm missing shots at matches due to elevation.

My load is 140gr ELDs w/ 42gr H4350 210M in Hornady brass. Avg Velocity is 2797 fps and SD is 10.

At 489 yards I was missing a 10-inch square by about 1/2 Minute over the top. At 605 yards it was the same. At 720 yards I was about a full minute over the top.

While at the match I increased the velocity on Ballistic AE to 2840fps, and the rest of the match I seemed to be right on, however I don't understand where my disconnect is. Any insight would be appreciated.

Did you ever "true" the muzzle velocity at a distance of 600-800 yards?

Before getting into things like light and other effects, it sounds like you did this mid-match.

 

[Dthomas3523]

Question on true-ing data:

I have a Tikka in 6.5 Creedmoor and I replaced the factory barrel with a 26-inch Patriot Valley Arms prefit. Accuracy is great, however when I put my data into JBM or Ballistic AE I'm missing shots at matches due to elevation.

My load is 140gr ELDs w/ 42gr H4350 210M in Hornady brass. Avg Velocity is 2797 fps and SD is 10.

At 489 yards I was missing a 10-inch square by about 1/2 Minute over the top. At 605 yards it was the same. At 720 yards I was about a full minute over the top.

While at the match I increased the velocity on Ballistic AE to 2840fps, and the rest of the match I seemed to be right on, however I don't understand where my disconnect is. Any insight would be appreciated.

Did you true your data prior to this?

If not, it’s pretty hard to diagnose the issue.

 

[Billiam1211]

Did you true your data prior to this?

If not, it’s pretty hard to diagnose the issue.

Unfortunately I don't have any ranges within a few hours that are more than 200 yards or access to private property. What I have done is simply go to matches in the area and I take notes on my misses.

With the factory barrel on my Tikka, JBM got me first round impacts out to 800+ yards while shooting PRS matches. Ever since I rebarreled my rifle I've struggled to get JBM or Ballistic AE to line up correctly. It seems when I adjusted the velocity in JBM to 2,840 fps it lined up my DOPE to what I was seeing in the field so maybe that's the answer

 

[wade2big]

Unfortunately I don't have any ranges within a few hours that are more than 200 yards or access to private property. What I have done is simply go to matches in the area and I take notes on my misses.

With the factory barrel on my Tikka, JBM got me first round impacts out to 800+ yards while shooting PRS matches. Ever since I rebarreled my rifle I've struggled to get JBM or Ballistic AE to line up correctly. It seems when I adjusted the velocity in JBM to 2,840 fps it lined up my DOPE to what I was seeing in the field so maybe that's the answer

That does suck that you don't have a range nearby to get your dope. This would be a much better tool than a ballistic calculator. That way you know what it takes to make the hit and you arent theorizing a solution.

 

[seansmd]

Unfortunately I don't have any ranges within a few hours that are more than 200 yards or access to private property. What I have done is simply go to matches in the area and I take notes on my misses.

With the factory barrel on my Tikka, JBM got me first round impacts out to 800+ yards while shooting PRS matches. Ever since I rebarreled my rifle I've struggled to get JBM or Ballistic AE to line up correctly. It seems when I adjusted the velocity in JBM to 2,840 fps it lined up my DOPE to what I was seeing in the field so maybe that's the answer

I would say it's hard to true your data in a match shooting off barricades under time pressure. You only need one spot 500-800 to get good accurate drop data to true the MV, some don't need to, most do.