Estimating velocity from dope.270win

[DesertDug]

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.

https://i.postimg.cc/MKXP7t3J/IMG-2580.jpg (https://postimg.cc/F75VmbQT) https://i.postimg.cc/X7h2QFtG/IMG-2581.jpg (https://postimg.cc/9rdtf4mC)

[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.

[scootergisme]

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

[DesertDug]

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.

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/showthread.php?61854-110e-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/682659/caldwell-rock-jr-rifle-front-shooting-rest , https://www.midwayusa.com/product/735047/caldwell-universal-deluxe-rear-shooting-rest-bag-nylon-and-leather-filled

[scootergisme]

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.

[celltech]

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?

[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.

[DesertDug]

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

.020 jump to lands.

[DesertDug]

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.

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.

[Robinhood]

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.

[CFJunkie]

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.

[DesertDug]

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.

[CFJunkie]

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.

[CFJunkie]

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.

[DesertDug]

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.