Reply With QuoteThere are lots of causes for vertical stringing -- rifle, scope, sandbags or bipod issues, shooting technique, reloading issues and on and on. I think we're going to need more info to offer anything helpful. What are you shooting and how?
I am having trouble with vertical spreading of my groups. I shot a 6 shot group and the horizontal spread was a max of 3/8" (100 yards) but the vertical was 1 1/8", although there were 5 shots within 3/4", which isn't terrible but the gun has done much,. much better than this in the past. With the expensive bullets it used to be from 1/4"-1/2". I noticed the last few times I was shooting that it seemed to be giving quite a variation on the vertical. I thought initially it could be the brass but the Savage 223 does not seem to do it with the same brass but it is possible I happened to get lucky with the brass on the Savage. I did seem to think there was a variation in the neck tension when I seated the bullets. Some seemed about right and some seemed to take little effort to seat. This is a Remington 783. I thought it was more accurate than the Savage but the Savage is either getting better with more rounds through it or I am getting more used to the trigger. The Savage shoots about the same as or maybe even a little better than the Remington did at one time.
There are lots of causes for vertical stringing -- rifle, scope, sandbags or bipod issues, shooting technique, reloading issues and on and on. I think we're going to need more info to offer anything helpful. What are you shooting and how?
Remington 783, .223, Bushnell Nitro 6-24 scope, 69 grain Sierra, 25 grains CFE 223, CCI primer, Winchester brass,, 2.27" OAL, rest is something like what Caldwell makes that supports both the forearm and butt of the stock. Brass has been annealed. I would estimate 1800-2000 shots on the barrel.
Vertical stringing as mentioned can be caused by alot of items. I would also try working down in .2gr increments and see if the vertical gets better.
From your description this is a new thing? The rifle used to shoot better using same loads and shooting technique? It does not change POI with barrel heat? It does not change POI as the barrel gets dirty?
Did all the rounds you fired that day do the same thing? Did they climb or fall over time or was it random?
Originally Posted by charlie b
Usually the first two shots are very close, then the third one is low. After that they all seem to be low but not a great amount. I never let the barrel get more than warm. I will stop after one group many times and let it cool for the next. I suppose I could clean it and see what happens. The powder was .3 grain higher than usual but the regular charge was doing the same thing with the vertical problem. I think I will clean it very well and drop down to the previous charge. It used to shoot very well not long ago. At first I thought it might be the military primers I had. They are responsible for a lot of misfires in the Axis and even a few in the Remington but I have them used up and am using the CCI primers now. I can't believe the barrel would be shot. I am extremely careful not to get it hot and use a mid range powder charge as a rule, sometimes even on the lower side with the lighter bullets.
With vertical, if everything else is right, the round is often saying, I don’t like the powder load. In Your case, I would recommend increasing the load in small increments. I almost always find My best node near the high end. Find the best powder group, then work on seating depth. How did You arrive at Your seating depth dimension? That needs to be fine tuned also.
With the number of rounds on Your rifle, way before now You should know if Your rifle groups best dirty or clean. Start with accurate loads and a squeaky clean barrel. Start shooting at a point on paper, keeping track of the impacts. A pattern will appear. I have some barrels that need 20 rounds of fouling to settle down.
If You’re using the kind of rest I think You are, they are not conducive to good accuracy. Best is a front rest and a separate rear bag, set up so no part of the rifle catches on anything upon recoil. Used dryer sheets or slick rags on the rest help the rifle slide freely. Repeatedly is important.
I don’t think Your Barrel is shot out. Best of Luck
Edit: since Your horizontal is right on, You may not need seating depth adjustment after all. See how it is after the powder adjustment.
Edit#2: Your Barrel throat could have developed a hard carbon ring? The net has many solutions for this, and sorry, I just can’t get into it tonight.
Last edited by GrenGuy; 10-30-2022 at 09:19 PM. Reason: afterthought
I would bet on cleaning. Like above, clean it squeaky clean. Make sure you get all the copper out. If in doubt use something like Pro Shot CU IV or Boretech Cu+. They work fast and the patches show a blue color if any copper is remaining. KG-12 works well (and is faster) but you have to look in the bore to see if any copper remains as they don't turn blue.
FWIW, there was a story a few years back. Hunting lodge had 'loaner' rifles. One was given to a client and the barrel split during the sighting in process (I think the client was injured). Turned out it had never been cleaned. The few shots per season had allowed carbon build up to the point that it acted as an obstruction.
Quite a common occurrence. I recommend shooting the Savage more. LOL!
Seriously, if does sound more like a cleaning issue. Doesn’t sound like a slow/steady decline as barrel wear would indicate. From what you are saying, this happened a bit more unexpected? Ehh.. back to my first comment. Just shoot the Savage.
^^^^^I don't want to wear out the Savage!!!!!!!!!!!!
The 783 is a nice rifle too and I am sure you know it is really a Marlin with a few changes after Remington bought them. A lot of people say they are more accurate than the Remington 700. I am going to clean it to beat the band and see what happens. It is, like many of the accurate, low cost rifles by various manufacturers made today, pretty much a copy of the Savage features that have proven to enhance accuracy.
My .223 12 FV that I shot yesterday with a cold, out of the car barrel, put the first-round high by almost 1 1/2 inches. The second round was about 3/4 inches high and slightly left - probably me.
The next 23 rounds, with the barrel temp from 85 to 104 degrees, were right at the point of aim.
I let the barrel cool to range temperature - 58 degrees and shot a different load.
The first two rounds were almost in the same locations as the first load.
The rest of the 23 rounds were at the point of aim.
This rifle has 4,908 rounds down the barrel. The first load shot 4 5-round groups with 77 grain Sierra SMK #9377 bullets @ 2993 fps muzzle velocity to an average of just under 0.2 inches. That load shot the smallest average group size that the rifle has ever shot.
The second load with a different bullet, Nosler CC 77 grain #53064 @ 2999 fps muzzle velocity shot 4 5-round groups to an average of 0.274 inches.
I don't think you will wear the .223 barrel out easily.
My oldest .223 bolt action is a CZ 527. It has 7,000 rounds down the tube and still shoots almost as accurately as it did when it was new.
I don't think you will wear out
^^^That is interesting. If you don't mind, a few questions:
How long do you wait between shots for the barrel to cool?
How often do you clean your rifle?
What powder charge do you use? Not specific grains but is it on the low, high or middle of listed charges?
It is encouraging that you have that many rounds through and still have accuracy. I may shoot my Savage a little more often knowing this. I would say at the present time the little Axis is my most accurate rifle, more accurate than my 22-250 Model 12 {I think that is the number} with the heavy barrel and considerably more expensive and more accurate than my 243 Model 10 in 243.
I don't know if you can wear out the .223 barrel :) The one I took off my Axis (22" varmint contour) had over 4000 rounds through it and the last groups still went into 1" at 200yds. I kept the barrel since it probably has several thousand rounds to go before it 'quits' shooting well. The last 2000+ rounds were 77gn SMK with 23.5gn Varget, 2850fps (chronograph).
This barrel was a gem. From cold to steaming hot the POI changed less than 1MOA vertical and nothing in the horizontal. The only time accuracy suffered was after 200 rounds without cleaning. I usually just let it go for about 100 rounds between cleaning (2 or 3 trips to the range).
What is the barrel contour? It has been mentioned that varmint and bull barrels do not have this problem. Many factory pencil barrels have vertical dispersion due to stress.
The Dunning-Kruger effect is alive and well.
Mr.Snerdly,
I use a temperature strip on the barrel.
Since the 12 FV has a varmint barrel, I assume that the internal temperature shown on the strip is lower than the bore temperature. I also have no idea whether the strip is very accurate, but it very representative of a relative temperature.
I find that the accuracy is outstanding when the barrel temperature is from 85 degrees to just over 104 degrees. If the barrel temp gets over 120 degrees, the POI is lower. The groups shot at 120 degrees are still about the same as with lower temperatures, but the POI is lower by 1/8 to 1/4 of an inch.
Usually, I stop shooting around 113 degrees and wait until the temp gets back around the 85-degree mark. The amount to time I wait depends on the ambient temperature. In the summer I use a fan to cool the barrel. At 90 degrees, the barrel heats up pretty fast - about 6 rounds get the temperature up to where I stop shooting so I shoot one 5-round group and then let the barrel cool. At 50 degrees, I might be able to shoot two groups, but the last shot in the second group is usually flirting with 120 degrees. At 35 degrees, l might even be able to shoot 3 groups.
I clean my rifle about every 100 rounds. I use Patch-Out to remove most of the copper, but I try to leave a bit of copper in the bore. Patches are used until there is no marks on the patch.
After cleaning, it takes about 2 or 3 rounds to get the barrel to 85 deg and also to get the barrel fouled. I am not sure which is the most operative factor.
With heavy bullets (60 to 77 grains) I use IMR4166, N140 and H4895.
With light bullets (52 to 55 grains) I primarily use N133 but have used H335 and CFE223.
The majority of the loads are in the mid-range of the load tables.
If you have looked at my posts showing the performance of my 12 FV, you will note that I load to match the Exit Time of the barrel to minimize harmonic vibration.
With heavy bullets (69 and 77 grain bullets shoot best in this rifle) I load primarily for the 12th reflection which puts the loads in the low middle of the load tables for most loading manuals.
For the 52 grain bullets, I generally load for the 10th reflection which puts the loads in the middle of the load tables since the powders are faster and the bullet inertia is lower.
Recently, I have experimented with the 10th reflection with the heavy bullets, but I have to be careful with which powders I use with 77 grain bullets because the loads for the 10th reflection can easily get over Pmax. H4895 gets just under Pmax so I have been shooting the 10th reflection 77 grain loads with that. The 69 grain bullets are far enough below Pmax at the 10th reflection so I can use any of the heavy bullet powders.
I also find that my .223 12 FV is my most accurate rifle. It is more accurate than my CZ 527 .223 or my Les Baer Super Varmint .223 AR.
I also find as you apparently do that my lower caliber rifles are more accurate over large samples of groups than my other rifles - .22-250s, 6.5mm Creedmoors, or .308 bolt actions. The average group sizes seem to get bigger as the caliber increases and it is incrementally linear. Even just taking the very best groups, I find the same relationship between group size and caliber.
I think the relative change in accuracy might be related to my ability to manage the recoil, that is, my ability to get back to my consistent set-up after firing the heavier recoiling rifles.
The heavier the recoil, the more I have to move to get back into the same set-up position so there is some probability that I won't manage to get the same precise set up after one or more shots in a group with the larger calibers.
I have never heard the term "reflection" used in reloading. Can you give more detail on this?
Heat should not appreciably effect a properly stress relieved barrel. If heat is causing vertical, your choices are to hope the first couple rounds count, or get a new barrel from a quality manufacturer. It’s a frustrating thing if you are shooting groups, competition, or sustained fire at varmints. Not a huge deal for game, usually only need one or two from a cold bore.
prdatr,
The following might help clarifying what I was referring to.
I submitted this text in another thread several years ago in response to a similar question ion an attempt to explain the process.
"If you're referring to exit time tuning, then I can provide some information.
The bullet exit time is the time it takes for a bullet to proceed down the barrel and exit the rifling.
It is both powder charge and barrel length dependent because those two factors along with bullet weight determine how far and fast the bullet moves down the barrel.
When the round fires, there is a shock wave that tries to expand the barrel and it proceeds down the barrel towards the muzzle and then reflects back to the chamber. It does that again and again until the bullet exits.
The concept is that barrel steel has a reflectionspeed that is far faster than a bullet can progress down the barrel and leave the muzzle.
The reflectionspeed is dependent on barrel length too, but it is also dependent on the amount of carbon in the steel.
Old barrel steel, pre-WWII vintage barrels, usually had a reflectionspeed of 18,916 fps.
Savage barrels use .3% carbon steel and have a reflectionspeed of 19,107 fps.
4140 and 4150 vanadium steels have a speed of 19,969 fps.
416R stainless steel has a reflectionspeed of 20,014 fps.
To do anything with the theory, you need to know what your barrel length from breech to muzzle and the type of barrel steel.
It doesn't matter what caliber because the reflection travels in the steel not the hole in the barrel.
I find that for most calibers 6.5mm and larger, with barrel lengths of 24-inches, the bullet exits somewhere around 1.15 to 1.3 msec. depending upon what charge you use.
For a Savage 24-inch barrel, the reflectionspeed is about 0.104 msec. to go from chamber to muzzle.
It takes another 0.104 msec. to get back to the chamber. (the 2nd reflection).
That means that you have to set your load to get the 10th or 12th reflection, depending on how close you are getting to Pmax.
At the 12th reflection in a 24-inch Savage barrel, the exit time would be 1.256 msec.
If you set up your load to get your bullet to exit the muzzle at that exit time, that reflected shock wave is at the chamber and the vibrations at the muzzle are minimum and the crown is the tightest.
The theory is that it should yield the best accuracy.
A 26-inch Savage barrel has a 12th reflection time of 1.361 msec.
A 22-inch Savage barrel has a 12the reflection time of 1.154 msec.
It you use a muzzle brake, a flash hider or a suppressor you need to include that length because the reflection travels all the way to the end before it reflects.
The complication is that the steel in those devices has to be considered because it most likely isn't the same as the steel in the barrel.
Most of mine are 4150 steel. (Colt AR flash hiders also use 4150 steel)
I have tested this effect for about 3 years now and, after minimizing my shooter induced variations and taking temperature into consideration, I have found that my 7 most accurate rifles actually do shoot the best when I load for exit time and get it within 0.002 msec.
I have one rifle (maybe because the steel batch was slightly different or my barrel measurement was a bit off) that likes to be 0.005 faster than I calculated.
QuickLOAD gives you exit time for loads that seems to be accurate enough for my testing.
There is a difference of about 0.060 to 0.090 in average group accuracy between having the exit time with the reflection at the chamber or the reflection at the muzzle.
I have found that with a new rifle, and I have used the approach on three new rifles, I get great results right from the first groups.
Then all I have to do is find out what bullets, powders, bullet weights, and jump the rifle likes the best. They all seem to be different but I don't have to hunt for nodes."
I hope this helped explain the concept and the process I use to reload using exit time.
The "reflection speed" is the speed of sound in the material. That's why different alloys have different characteristic speeds.
Why they call it 'reflection' is probably because they are looking for the reflection of the shock wave from the ends of the barrel. Kinda like a tuning fork.
There is a lot of confusion about this in places. Some folks think it is the same as barrel whip (it isn't). The theory is that the barrel is expanding and contracting as the shock wave moves through the steel of the barrel. The barrel does not move laterally or vertically (unless maybe there is a really bad stress point in the barrel that causes it to react in an asymmetrical manner).
Very interesting.
The Dunning-Kruger effect is alive and well.
Technically it is the speed of transmission of a shock wave in the barrel steel (since the s1ound waves of the blast propagate through the air) but the analogy of transmission is a good one.
The speed varies with the medium that the shockwave propagates through (the steel alloy in the barrel steel) while the speed of sound varies with the medium that sound wave propagates through - air, water, etc.
The caliber doesn't make a difference to the reflection time, only the steel of the barrel (and of the flash hider, muzzle brake, or suppressor if they are attached to the barrel).
The shock wave propagation is in the steel not the bore.
The propagation velocity in steel is between just under 19,000 fps and just over 20,000 fps (depending upon the alloy) while the nominal velocity of sound is from around 1100 to 1150 fps depending upon the temperature.
Air is a lot less dense than steel.
A 24-inch Savage barrel with 0.3% barrel-steel has a shock wave reflection time to go from chamber to muzzle of 0.1046 msec. It would take another 0.1046 to get back to the chamber (2nd reflection).
In that case, the bullet would accelerate from 0 to 2,500 fps in the length of the barrel, let's say 2 feet or 24 inches.
The muzzle velocity of the bullet and time in the barrel depends on the type of powder, powder charge, bullet seating depth and trim length of the load.
With a difference of almost 17x in velocity between wave propagation in steel and sound wave propagation in air, the reflection would go back and forth from 5 to 6 times from chamber to muzzle and back to chamber before the sound reached the muzzle or the bullet left the muzzle.
It would take about 1.1 to 1.3 ms for the bullet to exit the muzzle, depending on the barrel length and the steel alloy, assuming the absence of a muzzle brake.
It would take about 1.74ms for the sound to reach the muzzle at the end of a 24-inch barrel.
The bullet would be well out of the barrel and on its way down range before the sound arrived at the end of the barrel.
Yep, speed of sound in steel is the technical term. Common term used in explosives testing (and high power laser effects testing). And, yes, it varies with the density of the material, even in different alloys of steel or in other metals, or in liquids or gasses. Higher density means faster travel of the shock wave, which is why it is so much faster in steel than it is in air.
Exactly why I shoot down the idea of people talking about “loading for the bullet to exit on the number “x” reflection at 1.02m/s” -blah. I started picking up on this several years ago. Then I started wondering, are these people using filming equipment that can accurately capture 20K FPS reactions? And overlap software to correlate the top/bottom of reflection to the actual timing in M/S? The answer is, of course they don’t. It simply finding the published data of such & such a metal and the reflection numbers exhibited when a certain load is fired through it. It’s already established numbers we can easily find online. Basically it’s no different than simply saying “I’m load “x” grains of “y” powder and hoping for “z” velocity.
So why then do some continue to use the loading for reflection speak? Because it makes you sound really, really, SMART! LOL!
Yeah, I have no idea what that's about or if its even a real thing you can master.Exactly why I shoot down the idea of people talking about “loading for the bullet to exit on the number “x” reflection at 1.02m/s” -
So why then do some continue to use the loading for reflection speak? Because it makes you sound really, really, SMART! LOL!
I think you can, and we all actually do it without measuring it. It is called a velocity ladder. You shoot at several different loads and pick the one with the best accuracy. Above and below that point a little and the group opens up.
The guys who wrote an article on it a few years ago postulated that the traveling wave causes the barrel to slightly increase and decrease in dia. If the bullet exits during the 'large' portion of the node it was less accurate. If it exits during the small node it is more accurate. So, they quantified what we had all been doing all along.
Before this people thought the nodes were from barrel whip, which is totally different. And, it happens after the bullet leaves the barrel.
CFJunkie has shown that using the software to determine exit times severely reduces the amount of shooting needed to find a node. His groups reflect that.
IMHO, this is what good science is all about. But, I am a bit biased cause half my career was as a test engineer. Most of that time was spent trying to figure out what is making things go wrong.
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