Estimating velocity from dope.270win

I have a cds cap needing to get set up. I have landed on the classic load of 60 gr of H4831. Took to the range today on shoot 50, 100, and 200 yards. The thought is if I replicate the dope off same poi I could come close in guessing velocities and provide this information to Leopold to get the cap made.

I used the hornady billistic calculator. https://www.hornady.com/team-hornady...rs/#!/standard

shoot groups of 5@50, and 10 @ 100 and 200. Excluded the pulled shoots and cold bore. Took vertical measurements off aim point. These results were replicated in the calculator and I came up with 3,450 fps. This seems high out of the end of it's 25" barrel.

Anyone have a better way to approach this or am I headed in the right direction?

Here is a screen shot othe the dope chart with 50 yard zero and 200 yard zero for 3,450.
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Looking at the Hodgdon load center data for 4831, 62 grains pushes a 110 grain bullet 3214 f/s with a 24" barrel. You didn't specify your bullet or bullet weight, but it sound like 3,450 f/s would be too high of a velocity. What bullet and bullet weigh are you using?

Based on the information in the Hornady app you should be able to get close. The temp and altitude will also play into things and don't appear to be in that app? I use the Strelok app on my phone and it can figure out the velocity based on actual drop as well, but I have never used it.

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Originally Posted by scootergisme

Looking at the Hodgdon load center data for 4831, 62 grains pushes a 110 grain bullet 3214 f/s with a 24" barrel. You didn't specify your bullet or bullet weight, but it sound like 3,450 f/s would be too high of a velocity. What bullet and bullet weigh are you using?

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130 gn bullet. Cas compactly is 67.1 grains of water.

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Originally Posted by celltech

Based on the information in the Hornady app you should be able to get close. The temp and altitude will also play into things and don't appear to be in that app? I use the Strelok app on my phone and it can figure out the velocity based on actual drop as well, but I have never used it.

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What kind of velocity are you coming up with based on pics?

The hornady does have one with more variables such as altitude. I am shooting problem at 20' amsl, on the cost of Texas. Temp was 54 degs.

Nosler has published velocity of 3124 for 59.0 24" barrel. I am shooting 25" 5r 1-10 twist x-caliber barrel.

Due to the flat shooting nature I would drop the 50 and add a 300. What bullet did you use for your calc?

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Originally Posted by Robinhood

Due to the flat shooting nature I would drop the 50 and add a 300. What bullet did you use for your calc?

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Do not have access to 300 yards right now. Nosler 130 bt b.c. 0.433.

Does anyone one have the " quick load" application?

That seems a little high for 130 grain.

I setup a test 270 load in Strelok with your round. The Nosler .270 130 BST has a G7 of 0.199/G1 0.433. I am confused by your photos...did you set a 50 yard 0? Assuming you did, the 100 yard POI at 3400 should be -1.12 MOA and -.41 at 200. At 3100 fps the 100 is -.96 and 200 is .09.

I think that at these short distances it would be impossible to get an accurate read on your velocity. You can swing several hundred FPS and have variances that might be outside of you and your guns ability/accuracy to verify. Even at 500 years the difference between these speeds is only 2 MOA (5 and 7 drop).

Buy or borrow a chrono if you must have the most accurate reading. But if you had to guess, I would say you are closer to the 3100 range.

Yeah, careful with Nosler's claimed G1's; they have been sandbagging it for years.
G1's are always stepped by velocities, and many times not achievable in the carriage being fired.

Yes 50 zero.
100 yards +1.05
200 from group would be either 0, just below 0 or up to -1.5" average @200.

Here is what I plotted...

Celltech, so it may be pushing the higher velocities. I say this because the 100 yard is above poi. 3200-3400 range?

Is there a better way to go about this without crono?

In both plots the 100 yard is above POI...the minus sign indicates that. -0.96 for 3100 and -1.12 for 3400. No offense, but you were not exactly shooting bugholes at 50 or 100 yards. The drop difference between the 2 velocities is so slight that I would not trust the groups alone....especially at only 200 yards.

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Originally Posted by celltech

In both plots the 100 yard is above POI...the minus sign indicates that. -0.96 for 3100 and -1.12 for 3400. No offense, but you were not exactly shooting bugholes at 50 or 100 yards. The drop difference is so small between the 2 velocities is so slight that I would not trust the groups alone....especially at only 200 yards.

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non- taken. It was a gusty windy day. not the best for shooting groups. Any other ideas?

We need to be asking ourselves as individuals, just what it is we are attempting to do with the information were looking for.
Certainly today with the information available on various sites, owning a chronagraph isn't necessary in order to learn the velocity of our load. Just remember that tomorrow it might not be, at least exactly. Thats just the way it is, and owning the best chronagraph wont change any of it.
A hunter leaving from say Florida, with an elevation above sea level of almost zero, can prepare a chart similar to those produced by Celltech for a Colorado hunt @ 7000' before he leaves Florida.
But he should only be looking at that as ballpark information at best.
Certainly those who get warm feelings by making first round hits, need to be evaluating lots of information for a shot before they shoot.
But as a rule, that dosent work very well when long range hunting for various reasons. And note I did say "as a rule".
So the important thing then is having the ability to gather the information you just saw happen, and fix it for the next shot, assuming there will be one.
Another problem for a hunter, could be not actually seeing what happened on the first shot, which is another subject.
Look at the 2 charts prepared by Celltech, and evaluate the differences in actual distance the bullet would land from the aiming point even with the big differences in velocity. Then ask yourself would that make much difference for your second shot?
And if it does, then thats where you need be focusing your attention, and not with having a perfect chart.

thanks yobuck for bringing me back to reality. What I am trying to do is provide the best most accurate information to Leopold for setting up my CSI cap. The CSI cap replaces the elevation turret cap to be marked in distance, so no dope chart needs to be referenced proving quick adjustments. Now I understand that this type of cap is inherently not precise as it would be set for one velocity, elevation and temperature and will be slightly off if any variable changes. This is for a hunting gun and should get me within minute of kill zone.

Is there a way to calculate a velocity by charge and type of powder, weight of bullet and shape and column of case? Maybe I could see where that falls into possible speed. I just ant to get a good estimate to use with out buying another piece of equipment that I do not see using all that much.

DesertDug,

I would be a bit cautious about making a calculating velocity based on your three targets, because I think there is more shooter induced variation in the groups than you might think.
In fact, I believe your rifle may be shooting much more accurately than you believe.

First, the three targets show groups of 2.514 moa at 50 yards, 2.209 MOA at 100 yards, and 1.950 MOA at 200 yards.
Second, the horizontal dispersion on all three targets is a big contributor to the group sizes and to the determined POI position.
At 50 yards ,the horizontal dispersion is 1.285 inches or 2.5 MOA. I suspect that the majority of that (+/- .6 inches) is shooter induced variation. The vertical dispersion is actually about .7 MOA.
Note that the cold shot is high and to the right by 1.5 inches. I agree that you should throw that out. Most of my accurate rifles shoot a cold, unfouled shot high and to the right.

At 100 yards, the horizontal dispersion to the right is almost 2 inches, but the groupings are to the left compared to being on the right at 50 yards. That might indicate that you reset your set up when you shot at 100 yards. The horizontal dispersion to the right is about 0.7 inches. I suspect that the one far right hole was caused by the rifle butt resting on your shoulder bone instead of the inside edge of your shoulder bone.
Also note that the cold shot is low and in line with the aim point. I don't have one rifle that shoots high when it is cold and then low when it is allowed to cool down. I have rifles that shoot either high or low when cold but not both. I would suspect that the cold shot at 100 yards was shooter induced not barrel induced. You're right to throw it out, but it indicates set up anomalies more than barrel temperature.

At 200 yards, your POI is to the right like it was at 50. It is hard to understand why the 100 yard POI is to the left when the 50 and 200 yard targets show to the right without suspecting shooter set up.
You have 5 rounds that group within an inch at 200 yards about 0.5 inches low and 1.7 inches to the right - that's 0.5 MOA. If that is indicative of what your rifle is doing, you conclusions will be much different.
But you have 5 other rounds at 200 yards that have a 3-inch horizontal dispersion and a 1.7-inch vertical dispersion that are 2 inches low about 1.5 inches right with the same aim point. When they are included, your conclusions turn out completely different.
Those five shots don't look like rifle caused to me - they look like shooter caused variations.

Sorry to be critical, but there are too many indications of variations in set-up that would suggest that the overall groups are not statistically stable enough to make a judgement about velocity.
On the positive side, your 200 yard and 100 yard targets give indications that the actual median point of impact might be much more predictable if you could eliminate some of the horizontal dispersion and tighten up the occasional drop. But the resultant POI would be different than you are considering now.
Trying to conclude anything about velocity when including the large vertical and horizontal variations will only lead your conclusions astray.

thanks CF Junky. I agree that the groups are more a result of my shooting, and not that of the riffle. I will keep practicing and give this another try.

Don't get discouraged.
It took me 3 years of really working, shooting over 5,000 rounds a year, to get most of my shooter induced variations under control and I didn't have anyone to help point them out.

I hope that suggesting a few things to consider might make your personal quest a bit shorter.
As I said above, I see some good indications but there are enough variations to not be able to make any conclusions.

The first step is to recognize that you have work to do, and you have already done that.
After that, concentrate on getting your set up consistent and you'll be surprised how quickly things get better.

I would suggest that you find the rifle you shoot best - it probably fits you the best and you set up more comfortably and consistently - and then try to identify probable variations with every shot.
Your targets will tell you if you were right.
Everything you do to get consistent will carry over to your other rifles, but having the confidence to identify problems will give you the biggest payoff.

Jumping from rifle to rifle while you are trying to get consistent will mean that you will have to figure out everything on the fly with a lot of changing conditions.
It just makes things tougher.

I got back to the range yesterday and shoot some 100 yards with the load I have developed. I had someone run the "quick load" program on my load data and 3148pfs is what it came out to. I know this is still an estimate, but I will start working with this data.


Any way I am new to shooting a more precise riffle, which I am sure is capable of sub moa. I on the other had need to work up to its abilities.

The first grouping is 9 rounds with my scope set for a 50 yard zero, center point of aim.

The second group i adjusted the scope .75 moa. according to the data using 3148fps and shoot 13 rounds.

This got me very close in the vertical.

So what can you tell me about these targets?
Why would the first grouping be more centered horizontal but have a large spread? What form issue will cause this?
The second target seems like I was being more consistent but shots are now right of center. What do I need to do to correct this, as I did not change the vertical adjustment on the scope and must be shooter induced. At least the vertical tightened up some and the .75moa vertical adjustment seems close to if not a little over adjusted. .5moa looks like the correct adjustment.

Any advise or criticism is welcomed. Looking to improve.

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First off, 3148 fps sounds like a much more realistic velocity for the given load. As for your groups.... Was the rifle scrubbed clean before you started, did it get a bit tighter after laying down some copper? What are you shooting? How are you shooting it? Is it on a sled, bipod, bags? Plastic stock, composite stock? Does it have pillars? Is it bedded? Time between shots? So many variables here...and perhaps it's just not a sub moa system.

Grab the best shooter at your range that you can find and have them shoot it. If they shoot bug holes, it's you and not the rifle. If they shoot similar groups to yours, it's the rifle/load. Hopefully it's not a combination of both and then you can work on correcting whatever problem that it may be. I wish you the best! Scott

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Originally Posted by celltech

First off, 3148 fps sounds like a much more realistic velocity for the given load. As for your groups.... Was the rifle scrubbed clean before you started, did it get a bit tighter after laying down some copper? What are you shooting? How are you shooting it? Is it on a sled, bipod, bags? Plastic stock, composite stock? Does it have pillars? Is it bedded? Time between shots? So many variables here...and perhaps it's just not a sub moa system.

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Riffle was not scrubbed.
I am shooting a savage 110 .270 winchester, with hand lapped 25" 1/10 5r twist barrel by x-calliber. Stock has been action and pillar bedding.
This is a link to the riffles build http://www.savageshooters.com/showth...270-build-help
I tried to take my time. Each target was shoot over 20min. waiting between shoots.

Shooting off a front and rear caldwell rest system. https://www.midwayusa.com/product/68...-shooting-rest , https://www.midwayusa.com/product/73...leather-filled

Make sure that all screws (action, scope, scope base) are properly torqued. Try starting at 59.0 grains of H4831 with the same bullet, then 59.1, 59.2, etc. to see if that shrinks group size. If you don't get better groups with different powder charges, then try a different bullet manufacturer or a heavier bullet. Try not to get discouraged and frustrated. Nothing seems to work in those two conditions.

I was totally spacing out on the fact about the handloads...although we have been talking about FPS this whole time. So yeah, you might try getting a box of quality commercial ammo as a baseline comparison. If you really are hitting 3148 fps then you are at, or beyond, most top end loads. Dial it back a notch and see what you get. Are you seating the bullets to spec or just off the lands?

200yds isn't enough distance to use for this method of velocity determination. at 200yds it will always over estimate your velocity. You need at least 600-800yds. Best case scenario would bee 600-1000yds. A Magnetospeed Chronograph is even better.

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Originally Posted by celltech

Are you seating the bullets to spec or just off the lands?

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.020 jump to lands.

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Originally Posted by LoneWolf

200yds isn't enough distance to use for this method of velocity determination. at 200yds it will always over estimate your velocity. You need at least 600-800yds. Best case scenario would bee 600-1000yds. A Magnetospeed Chronograph is even better.

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I have succumbed to this reality, and will start to save for chronograph. In the mean time I am working on my shooting fundamentals, and thus my question regarding evaluating my target group. I was curious if the group can tell me what I may be doing wrong.

47-48 grains 4064 behind a 130SGK lit with WLR primers. It will blow baseballl size holes out the backside of central Texas Deer. Capable of sub moa at 250.

DesertDug.
Sorry I took so long to get back to you on your targets.
I'll ask a few questions that might get you thinking about what might be happening. If none of them apply, just consider my questions dumb.

What was the magnification of the scope and what kind of reticle does the scope have?
With a low magnification scope and a hunting reticle, the reticle can easily cover a substantial portion of the aim point at 100 yards.
If you can't be sure you are exactly on the aim point exactly the same way for every shot, you may actually be 'guessing' a bit about where you are aiming.
That might open up your groups a bit and add to whatever other variations you may be experiencing.

Did you find that you had to readjust your shooting position or reset up your position during shooting on either target?
I would suspect you did based upon the variation in POIs.
I assume you had to load the mag at least twice, so that would mean at least two set-up efforts.
Setting up, without having a consistent set of references that you're used to, can cause the POI to move around even though you think your aiming at the same aim point.

After any of the shots did you see the barrel move to the right away from the POA during recoil?
I suspect that it might have happened at least twice while shooting each target.
That would tell me that you had your rifle butt slightly toward the shoulder bone instead of in the slot inside your shoulder bone.
It pushes your shoulder back during recoil and moves you barrel slightly to the right - just enough to move the POI to the right.

Have you ever heard of your 'natural point of aim'? It helps me to determine if I have my body position in correct alignment.
Try this:
1) Set up with the reticle on the aim point and be prepared to fire but with you finger off the trigger.
2) Close your eye and relax for a few seconds without moving the rifle.
3) When you open your eye, is your reticle still on the aim point or is it to the right or left?
4) If the reticle is not still on the aim point, then when your body relaxed, your body reverted to your natural point of aim (the position your body would naturally be in). That tells you that you were 'muscling the stock'.
5) If so, move your lower body right or left to reset your natural point of aim. But don't move the barrel to re-aim, just move your lower body alignment.
6) Then set up again and repeat the process until you remain on the aim point when you open your eye.

I find that this exercise results in getting the next shot right on the point of aim.

When I am shooting the first few groups of a session, I do this drill religiously for every shot.
After I have the feel for my set up, I do it once at the start of a group.
If I find I throw a shot to the right or left, especially after reloading a mag, I revert to doing it for every shot for a while.

Did you find yourself moving in and out on the scope to get a clearer view of the aim point?
Moving your eye as little as 1/8 inch movement closer or further from the eyepiece can move the POI as much as 1/4 inch high or low respectively.
I find that I occasionally creep up on my scope a bit and have the next shot higher than my aim point, usually messing up a group.
It usually happens after the first few rounds when I am concentrating on getting a single ragged hole with the remaining shots and forget my set up routine.
One way I found to reduce the probability of sneaking up on the scope is to have the eye relief set up so at my 'perfect set up' my eye is at the point where the scope image is just on the border of being too far back - you know - when the black ring around the image begins to show.
If I set up and move my head back just a bit and don't see the black ring starting to appear, I stop and start my set up all over again because I was too close to the eyepiece and would have put the next shot high.

Lastly, did the barrel heat up during shooting at each target.
My .270 Winchester Model 70 has a hunting barrel but it puts the first two shots out of a cold barrel into one ragged hole. Then it moves the POI 1/4 inch to the right at 2 o'clock after the second shot and keeps moving it with each succeeding shot. That really destroys groups.
Since the .270 uses a really big load of powder, a hunting barrel heats up really fast.
I rarely have the patience to shoot groups with my .270 simply because I don't like to wait for the barrel to cool down to cold before I shoot the 3rd and 4th shot and then wait again to shot the 5th shot.
Since it is a hunting rifle and it puts the first two shots from a cold barrel right on POA, that's good enough for me since I never would get a third shot anyway when hunting. If I needed a third shot, I shouldn't be hunting anyway.

I know this sounds like it might be just too much trouble while setting up to be worth it, but believe me, once you do this a few times, it becomes second nature and you will really like the results.

CFJunkie, thanks for such an insightful and well written response. This is the type of information I was trying to get, so that I can better my understanding and achieve my desire for precision shooting. I know most would not be attempting this in the .270 Winchester round but there is a method to my madness. I am all self taught and have not been at this for more then 5 years, but I have reach a point that I need the great advise as you provided. I am more of a hunter type shooter with the desire for accuracy. I started out in the AR game, building and learning. I tend to buy once cry once if I have done my research to obtain the best or near top tier equipment for my budget. I had an old flattop savage 110e that was sitting around not being used as I learned the AR platform. Now the accuracy bug has got my attention. My shooting skills/ techniques are far from correct. So thanks. I will take your post to heart and see how I improve.

The plan is to get this .270 and myself shooting the best that I can, but this riffle is a hunting riffle. I traded and franking gun AR build for a Savage 12fv in 6.5 after I got done with the .270 knowing I was already ready to build on another savage action. Plan is to get that action set up for more of a PSR type shooter. As I save for this build I want to get the most efficient I can with my hunting set up.

Ok, so to answer some of your questions.
Scope is Leupold 3.5x10 vx-3i with a wind-led reticle. So yes more of a hunting type scope.
Not seeing exactly my POA is an issue I say I have. Especially as my eye sight is not as it use to be. I do tend to get better moa groups at 50 then at 100

Readjusting set up- guilty. I have been loading one round at a time. I have adjusted the placement of rests as I shot. Your right, I assumed that I was aiming at the same POA every time.

Barrel jump- You mentioned this in an earlier post and I was trying to be conscious of the jump as I shoot this outing. Sometimes the barrel did jump to the right. Sometime the jump was straight vertical as it should be as I understand. I need to be more aware of butt stock placement in the shoulder.

In all my research I have not come across "natural point of aim". This is great information will make sure that I practice this technique. I did try to get the rest exactly on target while not touching the riffle and then setting up to shoot and letting go to minimize riffle movement.

Eye relief- I was not aware that eye relief was so important. I have looked though dot scopes and have noticed that the aim point moved as the head moved, so make sense. So like archery, anchor point is very critical and I will start to consciously try to get this consistent.

Barrel heating up- barrel is a light puma contour. I tried to let riffle cool a few minutes between shoots, but am sure it heated up some. What effects should I be looking for that a heated barrel result in?

Once again, thanks for taking the time writing up such an insightful response in my quest.

The effect of barrel heating can be different in each rifle. It can be a combination of barrel heating and the amount of movement of the barrel in the stock. Yours is already bedded so any heating will probably come from the barrel.

On my 6.5mm CM, with a bull barrel with aluminum pillar bedding, the PIO drops down at 6 o'clock about 1/4 inch after the barrel gets to 113 to 122 degrees and stays there.
I admit I don't let it get too much warmer than that.
The internal barrel bore temperature may actually be higher than that because the LCD strip isn't calibrated and it measures the outside of the heavy barrel not the bore.
But the effect is repeatable so it is a good indicator for me on when to stop shooting and let the barrel cool.

On my .270 M70 hunting rifle with a standard hunting barrel, the POI moves out at 2 o'clock 1/4 inch on the 3rd shot in a group and then goes another 1/4 in the same direction with each successive shot. To see that, I don't stop and let the barrel cool within the group.
That really opens up my group sizes from two touching to being barely able to stay under 1 MOA at 100 yards after 5 rounds.
For hunting, it is very accurate but as a group shooter, it's a bust.

I assume you can see the bullets on your target at 100 yards with your scope set at 10X magnification.
(A white background helps and the targets in your previous posts would work fine.)

You will need to see each shot because you need to determine if there is a trend in movement due to increasing temperature.
I use a 5-14X 56mm VX-L Leupold (with the crescent shape cut out in the front optic to allow the big front optic to mount closer to the barrel) on my .270 and I can easily see the bullets on the target using 14 X magnification. I use 5X for hunting.

I suggest you set up with 5 rounds in your magazine, and adjusting your position as little as possible, shoot each shot (checking for natural point of aim if you're comfortable doing that).
Watch the results after each shot to see if you can see a trend in movement as the barrel get hotter.

One last bit of advice.
If you have trouble seeing the reticle you may have the reticle out of focus (that is not focusing on the same plane as the image).
If the reticle focus is not in the same plane as the image focus plane, it means your eye will have to change focus to see the reticle and then refocus to see the image of the target.
When the reticle is focused on the same plane as the image, your eye won't have to refocus and both the target and the reticle will be clear all the time. You will have less eyestrain and fewer problems.
The rear objective rotates to focus the reticle for your eye to get the two planes focused on the same plane. The rear objective sometimes has a small dot and mark to allow you to see how far you moved them off the initial setting. The initial setting is for perfect eyes and I know I don't have them.
The best way to adjust the reticle focus is to point the scope at a white wall. The reticle should be instantly in focus when you look into the scope. Rotate the rear objective and see if it gets better or worse and pick the best position.
With my old eyes, I have to do this with every scope. If I didn't do it right, I find that after about 15 rounds, I have trouble seeing the reticle when focused on the target image. Then I know I didn't adjust it quite right.

If you wear glasses or contacts:
I used to shoot with progressive prescription glasses rather than contacts because I use monocular vision contacts so I can read without reading glasses with the weak prescription on my shooting eye.
Turns out that the progressive grind and most bifocals have the least effective grind on the edges of the lens and when I am shooting through a scope that is the part of the glass that I am looking through.
A wise optometrist who was also a shooter suggested that I get shooting glasses with just the normal prescription, without the progressive grind.
They work much better and I had the plastic lenses in my shooting tinted yellow to help in the dim morning light.

I forgot to comment on vertical barrel jump:
Is it possible that one of the sling swivels is bouncing against your front or rear rest.
The front swivel hitting the front rest on recoil will cause the barrel to jump.
Since I use a Sinclair F-Class bipod, the front swivel is the bipod attachment point and adds stability rather than causes barrel jump.

Also if the rear swivel gets caught on the rear rest, it can bounce the stock and cause movement.
I remove the rear swivels when shooting with a rear bag after finding that they were hitting the rear rest. My Protektor rear bag has a black mark where they were hitting before I removed all of them.
If you use a sling on you hunting rifles, you can still take out the rear swivel when you're bench shooting and put it back before you go hunting.

ya the front swivel stud is bouncing against the rest. I have tried having the stud in the front of the rest and rear of the rest. The rear seems to work the best.