Am I really spitting these Bergers at 3200 fps????

[PowellSixO]

I've used several ballistic programs to get my drops and I've entered everything as acurately as possible. With every ballistic program I get very very simalar drops (pretty much the same). Using the drops given from the info I put in, I shoot high at all distances past 100 yards. I checked, checked, and double checked everything to see where my mistake was. I couldn't find any. I then went to the range and figured out exactly what my drops were just from shooting and making adjustments. I was given 7.3 moa's for 500 on the balistic programs, but I'm only needing 6 moa's to be right on at 500. With this information it seems that I'm shooting these 168 gr bergers much faster than my chrony says I am. My chrony says 3050 fps, but with my corrected drops it says I'm at 3200 fps. That's fine and dandy, everyone wants more speed right . But my question is, how am I shooting the VLD's at over 200 fps faster than what's listed in the load data I've found and I'm not even at max load? Here is my info just so someone can double check me.

4500 ft elev.
60 degrees
25-30 % Humidity
168 gr Berger VLD Hunting
3050 fps According to my Chrony
2.18" Scope Height
24" Stock Barrel
Rifle info in Signature
Need 6 moa to be right on at 500 yards (A 100% true 500 yards checked by multiple range finders)

 

[bigngreen]

Odds are that your optic is moving more per click than you have in for a value.

 

[Skidro]

Odds are that your optic is moving more per click than you have in for a value.

I agree

 

[PowellSixO]

This makes sense. I never thought of that before. Thanks.

 

[blksno]

VERY easy to check that.
Get your zero and fire at 100yds.
Crank up 20 MOA and take a shot. It should impact at 21" (+/- your level of accuracy)
(1.0472" = 1 MOA so 1.0472 x 20 = 20.944 or basically 21")
You can use different adjustments, but I use 20 because it rounds out really close to 21" . Lots of videos online about doing a scope tracking test.

Crank back to zero and take a shot, then crank it 20 MOA down and you should be 21" below your zero.

Some ballistic programs can compensate for tracking issues. If you're dialing 20 and your impacting significantly off, then you need to start a data book to know exactly what you're dialing.



I saw your atmospheric data listed, but didn't see a pressure given.
Even if you're inputing altitude, temp, and humidity...if you don't know your true pressure...you're really just guessing. It doesn't make much difference at 500 but if it's significantly off, it's an issue at longer ranges.

Being off at one range isn't uncommon and velocity could be the issue. First make sure your scope is tracking correctly. If it is...then check your drops at about 4 different ranges, 2, 4, 6 and 800 and you'll be able to calculate your true velocity.

 

[PowellSixO]

VERY easy to check that.
Get your zero and fire at 100yds.
Crank up 20 MOA and take a shot. It should impact at 21" (+/- your level of accuracy)
(1.0472" = 1 MOA so 1.0472 x 20 = 20.944 or basically 21")
You can use different adjustments, but I use 20 because it rounds out really close to 21" . Lots of videos online about doing a scope tracking test.

Crank back to zero and take a shot, then crank it 20 MOA down and you should be 21" below your zero.

Some ballistic programs can compensate for tracking issues. If you're dialing 20 and your impacting significantly off, then you need to start a data book to know exactly what you're dialing.



I saw your atmospheric data listed, but didn't see a pressure given.
Even if you're inputing altitude, temp, and humidity...if you don't know your true pressure...you're really just guessing. It doesn't make much difference at 500 but if it's significantly off, it's an issue at longer ranges.

Being off at one range isn't uncommon and velocity could be the issue. First make sure your scope is tracking correctly. If it is...then check your drops at about 4 different ranges, 2, 4, 6 and 800 and you'll be able to calculate your true velocity.

Thanks for that. That's some very good info. I'll do just that.

 

[Deleted member 71114]

You can always use a large carpenter rule, somewhere in the 72" version measure out 100 yards and hang the rule vertical using a level. With your gun solid in a gun vise and aiming at the top of the rule you can dial a moa or mil and check the travel, continue and record how accurate it is or how aggressive the click values are. Then make the corrections in your program.

While doing this you will also see if the reticle tracks square with the carpenters rule.

Cheers
oneshot.onehit

 

[PowellSixO]

Ok, I went to the range last night and brought my chrony with me. I set up my fancy power wheels box with a piece of brown rapping paper on it. I drew a straight line on the box and put a mark at the base of it. I also put marks up the line at 5", 10", 15", and 20". I adjusted my scope according to each mark and fired 2 at each adjustmnet. All of them were right on the money. They all tracked straight up the line I drew. So I started to think about the chrony again. My velocities where taken when I was working up my load for my rifle. The last time I used my chrony, I only had 80-90 rounds down the pipe. Now I'm sitting closer to 300. So I set up the chrony again last night and fire 5 rounds through it. To my surprise, my average was 3159 fps with a difference of 12 fps between the 5 rounds. Is it possible for a barrel to get faster? Thanks everyone so far for the help.

 

[BMF]

Very possible, and probable that it gets faster and it should top out between 80-120 rounds.
But 3159fps........that's smoking. Any pressure signs?

Also if you're not comfortable with your chrono reading you can always shoot at an extended range, 400, 500, or whatever really. But keep your turret zeroed. Then just see how many inches it drops at any of them ranges. Then punch the 3159fps info into your ballistic program and see if it matches your actuall drop in inches.
Brent

 

[PowellSixO]

Very possible, and probable that it gets faster and it should top out between 80-120 rounds.
But 3159fps........that's smoking. Any pressure signs?

Also if you're not comfortable with your chrono reading you can always shoot at an extended range, 400, 500, or whatever really. But keep your turret zeroed. Then just see how many inches it drops at any of them ranges. Then punch the 3159fps info into your ballistic program and see if it matches your actuall drop in inches.
Brent

I agree, that is smokin!!! I am extremely sensitive to detail when loading my rounds. No I don't have any pressure signs. I was able to shoot 71.5 gr of H1000 before I had a heavy bolt lift and had signs of high pressure when finding my max load. I'm only shooting 69.4 gr as of now. I have been using the same 40 pieces of brass for 7 firings now. The brass is in good shape still, so I'm where I need to be. Tomorrow I am going to go back to the range and do exactly what you mentioned. I am going to get my drops from 200 all the way to 800 yards. Then I am going to input the information to get my fps. I don't really trust my chrony, considering how cheap it was to buy. I'll be sure to take pictures of everything this time to show everyone. I took the day off from work to do it. My elk hunt is getting too close for me to not be exact on my drops. From 100 to 500 I am 100% confident in my abilities. But from my scouting trips, I may have to take a 600-700 yard shot which I feel about 75% confident in taking right now. 75% isn't enough for me to take a shot at this time. I'm a firm believer in being 100% sure in your shot. So hopefully in the next two weeks I can be at that point.

 

[BMF]

Good luck. Even though i dont own a 7mm, I am interested in your results.
Brent

 

[bigngreen]

Usually 69gr of H1000 in a 7 mag with a 168 Berger will be right in the 3000fps range in every one I've loaded or know of, it's kind of a go to load.

 

[PowellSixO]

Long overdue update. I got a new chrony. The old one was jacked. Here is the real number. I knew it was to good to be true. Haha.

 

[den]

did you get it figured out on the drops ? when I run your numbers through jbm with a 200 yard zero it gives right at 6 moa up for 500 yds