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6/25/2018 7:04:05 PM
Posted: 7/7/2018 1:57:54 PM EDT
MAde it out to the "long" range today first time with my new 18 inch 223 wylde Green mountain barrel. I had previously zeroed and chronoed the rifle at 100 yards using Magtech 5.56 77gr otm (mk262 clone) I went through a 50 rounds box and averaged 2743 fps with the chrono 10 feet in front of the rifle. Im in central florida so elevation is almost 0 but temp was 75* and 80% humidity when I zeroed. Today on the "500" yard line which turns out is really 475 that really through me off the first time I went out there... It was 85* 100% humidity very little wind maybe 2mph at most.

I am using strelok pro and have all of my info entered such as scope height (2.75in) bullet data ect

I started at 200 and worked out to 400 yards with calculator and everything was dead on. Once I switched to the 475 yard target (they call it 500 but it isnt really) Strelok said dial up 10moa. The targets are full size IPSC silhouette steel targets and holding center mass with a 1moa hold for wind at the target I was hitting high. I backed down my elevation in increments until I was hitting POA which ended up at 9 moa. My Scope is a Bushnell Enage 2.5-10 in MOA and it tracks true

What would explain that difference in elevation? Is it just the calculator gets you close and actual impacts can vary? Or am I doing something wrong?

I am new to the long range shooting and trying to do and learn as much as I can with the 223 before investing in a larger caliber to go further out
Link Posted: 7/7/2018 2:17:05 PM EDT
Link Posted: 7/7/2018 2:32:42 PM EDT
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Originally Posted By Rob01:
Ballistic calculators aren't always on 100% of the time. They get you close. Same ammo lot number? Did you recheck your zero? The temp difference might have done it if you were still using 75 degree data but if you changed it to 85 then it wasn't that. The humidity won't effect anything at those ranges. Just make sure everything is right in your program inputs. Once you start going out farther even little mistakes will start showing up.

Log that data and next time out you just dial it in and make a hit. Actual data always trumps programs.
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Yeah ammo is all from the same lot. I had bought 500 rounds last time and all the boxes match. I did not recheck the zero at 100 this time though the last 3 times I went to the range and shot 100 yards I used the same ammo with the same zero and nothing had changed.

So at this point I should make log book/dope sheet the calculator works fine out to 400 past that I need to put rounds on target and log it and build from there
Link Posted: 7/7/2018 11:36:25 PM EDT
Calculations are just a guide. My experience has been the same as yours... calculations called for more than what was actually needed.

Like mentioned above, best data is your live-fire data, then confirm at a later date under the same conditions.
Link Posted: 7/8/2018 2:25:41 PM EDT
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Originally Posted By Bowhntr6pt:
Calculations are just a guide. My experience has been the same as yours... calculations called for more than what was actually needed.

Like mentioned above, best data is your live-fire data, then confirm at a later date under the same conditions.
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Exactly this.

Calculators are just to get you in the ballpark; you need to actually shoot at known distance and record your come-ups. Then rinse/repeat a few times until you've got an established pattern.

It can be frustrating as ammo lots (if you're shooting factory), and environmental conditions make quite an impact.

Hence why it can be so difficult to get "first round hits" at extended ranges.
Link Posted: 7/8/2018 5:33:40 PM EDT
I wrote down my adjustments so next time I go I know where to dial and will see what happens
Link Posted: 7/9/2018 8:30:57 AM EDT
[Last Edit: 7/9/2018 8:31:27 AM EDT by Evile]
So I started doing more research and came across this video on truing muzzle velocity which described exactly what I experienced. So I found in Strelok pro the option to do this, Entered my rage to target and how many clicks it took to be on target hit compute and get a muzzle velocity of 2893 fps which is much higher than my previously chronoed 2743 fps.

So Ill take this info and apply it to my next trip to the range. Hopefully the owner is there this time and he will qualify me for the 1000 yard range and I can push the 556 out as far as i can

Link Posted: 7/9/2018 8:50:28 AM EDT
[Last Edit: 7/9/2018 8:57:26 AM EDT by popnfresh]
I"ll go against the grain here, IME ballistic calcs are very accurate. They should get you with in a 0.1mil or two out to 1k yds providing there are no odd drafts.

Garbage in garbage out is the saying. Most who have issues are using sloppy inputs.

So did you do a tracking test and input the tracking error into the calc?

Did you input your exact zero offsets on this day?

Did you get velocity data at the time of shooting?

Did you input all atmospheric data collected from your Kestrel?

No to any of those and a few more obvious ones and you will have problems.
Link Posted: 7/9/2018 9:11:56 AM EDT
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Originally Posted By popnfresh:
I"ll go against the grain here, IME ballistic calcs are very accurate. They should get you with in a 0.1mil or two out to 1k yds providing there are no odd drafts.

Garbage in garbage out is the saying. Most who have issues are using sloppy inputs.

So did you do a tracking test and input the tracking error into the calc?

Did you input your exact zero offsets on this day?

Did you get velocity data at the time of shooting?

Did you input all atmospheric data collected from your Kestrel?

No to any of those and a few more obvious ones and you will have problems.
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I did a tracking box test when I first got the scope and it tracked true, each adjustment impacted where it was supposed to.

No to the next two items. I didn't check my zero before I started shooting. I had confirmed my zero the last 3 trips and my turrets lock and had not moved. And I did not bring my chronograph this trip.

I don't have a kestrel but I did get temp humidity and wind from a different device.
Link Posted: 7/9/2018 12:21:07 PM EDT
[Last Edit: 7/9/2018 12:29:24 PM EDT by popnfresh]
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Originally Posted By Evile:

I did a tracking box test when I first got the scope and it tracked true, each adjustment impacted where it was supposed to.

No to the next two items. I didn't check my zero before I started shooting. I had confirmed my zero the last 3 trips and my turrets lock and had not moved. And I did not bring my chronograph this trip.

I don't have a kestrel but I did get temp humidity and wind from a different device.
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If you input all the data precisely you can expect better results.

Before doing any calibration to the app I would first try it with all the correct info that you can gather.

So with no Kestrel you could input air temp, 50% humidity, and 29.92 in/hg(assuming Florida).

Measure MV just before shooting and use that number. Keep your ammo out of the sun and away from hot things(keep it ambient temp).

Fire a group and measure zero offsets and put those into the calc. You don't need to re-zero the scope.
If you are 1.125" high of aim point at 100yds, just put that into your zero info. +1.125.

Then of course distance to target should be accurate as possible.

If you true the app for only one distance or a short distance then it may correct the wrong variable and be off at every other distance past the truing distance.

Here is where the zero offset is.
Attachment Attached File
Link Posted: 7/9/2018 12:43:49 PM EDT
Sounds to me like you have a slight BC correction on the bullet plus a switch in wind such as a tail wind. With high humidity sometimes you get a little higher lift of the bullet. I think Strelock pro uses Density altitude which sometimes doesn't account for over 80% humidity. But that's why a log book is so important that way the next range visit you can recheck your actual shooting data to the apt data.
Link Posted: 7/9/2018 12:51:27 PM EDT
It's summer time in Florida which means 90*+ Temps and 80%+ humidity

I had zerod the rifle a month ago in the morning when it was 75 but still high humidity.

Would that temp difference cause the shift in poi?

When I go back next time I'll check my zero at 100 and see if it's moved and input the offset if it has changed.
Link Posted: 7/9/2018 1:39:39 PM EDT
[Last Edit: 7/9/2018 1:40:57 PM EDT by popnfresh]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Evile:
It's summer time in Florida which means 90*+ Temps and 80%+ humidity

I had zerod the rifle a month ago in the morning when it was 75 but still high humidity.

Would that temp difference cause the shift in poi?

When I go back next time I'll check my zero at 100 and see if it's moved and input the offset if it has changed.
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Humidity has very little effect, it would be the least of your problems, leaving it at 50 or 60 or 70% would be fine since you don't have a Kestrel.

Your ammo temp difference can cause a big change in velocity.

A different MV can change poi from your zero.
Link Posted: 7/9/2018 1:48:42 PM EDT
[Last Edit: 7/9/2018 1:49:19 PM EDT by Evile]
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Originally Posted By popnfresh:

Humidity has very little effect, it would be the least of your problems, leaving it at 50 or 60 or 70% would be fine since you don't have a Kestrel.

Your ammo temp difference can cause a big change in velocity.

A different MV can change poi from your zero.
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So this is where the logbook comes in right? Write this sessions results down next time I go out do the same rinse and repeat?

Other than checking mv each time I go with the chrono

Anyone got a link to a good logbook or spreadsheet to track this and keep it organized?
Link Posted: 7/9/2018 2:06:40 PM EDT
[Last Edit: 7/9/2018 2:08:02 PM EDT by popnfresh]
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Originally Posted By Evile:

So this is where the logbook comes in right? Write this sessions results down next time I go out do the same rinse and repeat?

Other than checking mv each time I go with the chrono

Anyone got a link to a good logbook or spreadsheet to track this and keep it organized?
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Yes, if you are ever without your gizmos a good log book and/or range cards are all you have .

I just use those little 3"x5" notebooks, one for each rifle.

Everytime out I write down ammo temp, air temp, wind, pressure, humidity, DA, MV data, # of rounds fired, # of rounds since cleaned, and load details.

If I am shooting long range I get all the above plus predicted drop from calc and actual drop at each distance.
Link Posted: 7/11/2018 10:26:08 PM EDT
Quite honestly, OP, I think a few more details would help. Let's start with your brand new barrel. What is the twist in it? Do you know if it is an accurate barrel, ergo, have you shot quality ammo through it and produced any sub-minute groups?

My assessment is a simple one. I'm going to say much of your issue is your ammo. I speak from experience when I say Magtech makes straight shit ammo. I know you ran the ammo over a chrono, how many rounds did you run and what were your SD and ES valuations?

Obviously, when your targets are closer in, variances in your ammo's velocity are negligible. However, as you start to stretch legs (which 500 yards certainly is with .223). What may be a relatively minor variance at 300 becomes much more amplified at 500.

My experience is anecdotal, so I did find this article for you, which was actually a great read. Specifically, it stated, the CBC (which is Magtech), "had one of the higher standard deviations of all ammo tested."

Not knowing the details with regards to your barrel, and again, from all of my personal experience, I'd recommend you go grab a quality 69gr load, such as some Federal Gold Medal Match or Black Hills 69gr and run it.

IMHO the CBC 77gr you're shooting is just a bit better than, say, some Wolf or Fiocchi, but not on the same playing field as FGMM or BH. I believe it is great ammo for plinking and what not, but I would not rely on it for precision or any kind of accuracy testing on your rifle.

Good luck. Keep us posted.
Link Posted: 7/11/2018 10:47:14 PM EDT
[Last Edit: 7/12/2018 8:10:38 AM EDT by Evile]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By FALex:
Quite honestly, OP, I think a few more details would help. Let's start with your brand new barrel. What is the twist in it? Do you know if it is an accurate barrel, ergo, have you shot quality ammo through it and produced any sub-minute groups?

My assessment is a simple one. I'm going to say much of your issue is your ammo. I speak from experience when I say Magtech makes straight shit ammo. I know you ran the ammo over a chrono, how many rounds did you run and what were your SD and ES valuations?

Obviously, when your targets are closer in, variances in your ammo's velocity are negligible. However, as you start to stretch legs (which 500 yards certainly is with .223). What may be a relatively minor variance at 300 becomes much more amplified at 500.

My experience is anecdotal, so I did find this article for you, which was actually a great read. Specifically, it stated, the CBC (which is Magtech), "had one of the higher standard deviations of all ammo tested."

Not knowing the details with regards to your barrel, and again, from all of my personal experience, I'd recommend you go grab a quality 69gr load, such as some Federal Gold Medal Match or Black Hills 69gr and run it.

IMHO the CBC 77gr you're shooting is just a bit better than, say, some Wolf or Fiocchi, but not on the same playing field as FGMM or BH. I believe it is great ammo for plinking and what not, but I would not rely on it for precision or any kind of accuracy testing on your rifle.

Good luck. Keep us posted.
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The barrel is a green mountain 18inch 223 Wylde 416r ss fluted barrel 1/8twist. I've put several types of match ammo nosler and gorilla 69gr have produced the best groups all sub moa. The magtech 77gr stuff is consistently moa or better. I shot full box of 50 over the chrono, I'd have to back and check the SD on them.

Edit.. The Caldwell app does not doesn't work with my LG phone so I use an older s4 with it so I don't have every chrono result saved but here is one batch of 10 shots.

Created: 06-07-2018 07:38:46 AM
Description: magtech 5.56 spr
Notes 1: magtech 5.56 HPBT MatchK 77.00 0
Notes 2:
Distance to Chrono (FT): 0.00
Ballistic Coefficient: 0.367
Bullet Weight (gr): 77.000
Altitude (FT): 0.0
Temp: N/A
BP: N/A
Shots
#

FPS

FT-LBS

PF
10 2736

1280.08 210.67

9

2799

1339.71 215.52

8

2744

1287.58 211.29

7

2726

1270.74 209.90

6

2729

1273.54 210.13

5

2761

1303.58 212.60

4

2730

1274.48 210.21

3

2759

1301.70 212.44

2

2750

1293.22 211.75

1

2748

1291.34 211.60

Average: 2748.20
StdDev: 21.66
Min: 2726
Max: 2799
Spread: 73
True MV: 2748.20
Shots/sec: 0.37
Group Size (IN): 0.00
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