WHY is my first shot high?

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I think you will be fine with that rifle or any other rifle when you become familiar with it.Before the .243 I hunted with a scoped Marlin 30-30 for 25 years.I missed a couple and then settled down and took 16 with it.
 
My next chance to try some more cold bore data collection will be either Tuesday or Saturday. Will see if this grease trick holds up. If it does, I may have a spare match barrel laying around for nothing. Maybe I'll make yet another rifle!
 
There are a number of possible causes, but my experience is simple, that a cold bore shot is always off the center group of a warm barrel. You'll probably, and likely, never know what is the culprit, it's just the nature of long guns in general. I have a number of high powers, and all of them shoot consistently high, low, or what ever with the first cold shot. Now if you start having trouble with groups, then you have something that needs tending to.

I have a 7 mag that shoots extremely high on the first cold shot 3"+ depending on the load I'm using, always has, and probably always will, but after that first cold one, it will shoot 1/2" all days long at 200 yds. if I'm doing my part that is.
GS
 
Well, you may be right. But I have a couple of rifles don't act that way. I have an AR 15 where the first shot groups normally and an accurate Mosin whose first shot also groups with all the rest. My benchrest 6ppc first shot appears to be insignificantly off from a hunters perspective. But this 7mm08 was 2" off. Last test after grease cleaning was encouraging. Will report another test hopefully tomorrow.
 
Here is my 2nd test of the cold-bore shots using the "grease" technique. I'm not exactly following the directions, but I'm close. Ran greased patch up the bore multiple times, until no more carbon picked up, finished with a dry patch.

Was unable to measure any velocities today. (I did however, add a homemade diffuser after these shots, made out of several sheets of white paper, and was able to get some velocities from a Mosin Nagant that showed the first shot was slower than the rest, uncleaned)

THe first shot is still high, but not nearly as high as I had been experiencing before, so it seems to me that this IS helping. The first shot of this cold bore test is less than 1.5" higher than the middle of the remaining shots -- this is probably do-able as a hunting rifle. First shot anywhwere from 0 to 1.5" higher than the typical group, gives tolerable accuracy to 200+ yards.

Shilen has notified me that they are about to send my new match barrel to the chambering dept -- so maybe I'll have a new barrel soon.
 

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If that helped... then I'd be inclined to believe that it's your barrel. ... and a rebarrel will completely resolve the issue.

Thanks for your diligence in updating this Doc. Can't wait to see the resolution.
 
I am stoked! I can't wait to see the holes that shilen makes for you. I've been watching this thread like a hawk. The only way it would be any more interesting for me is that if you were getting a brux screwed on.
 
Interesting thread. As I started reading the thread, my initial thought was that the receiver face needs to be trued - once it warms up, it pushes on the barrel unevenly, so the remaining shots go to a different place. Orkan touched on this in his earlier post. I'd be interested to see if your new barrel fixes the problem.
 
"There's no meat in the freezer and I know why. . . Because I shot high, because I shot high, because I shot high. . ."

Sorry, I couldn't resist. I'm guessing your bore is just very fouling and / or temperature sensitive. It really shouldn't be that bad, though, unless your barrel is very thin and lacks rigidity. It also could have to do with how it interacts with the stock. Hopefully whatever you try fixes it.
 
OK, gang, it is looking like HUMMER70 absolutely NAILED it. Here are today's cold-bore test results, which show a striking improvement over my results before adopting his "greased patch" technique.

Shot #2 is in the black to the left. Pen doesn't show up there well. Shot #4 is inexplicably "off". The rest are very well grouped.

Annealed, many-times-used, full-length sized (ran in and out of sizer 3 times), then trimmed, beveled, smoothed in steel wool, neck sized, 41.2 grains Varget (my summer-time-load, as the 42 grain was over-pressure recently), 120 grain Sierra spire-point hunting round, seated to just about 10 thou off the lands from previous tests. Seater is more consistent if you run it up into the seater twice.

HERES THE KEY: (adapted from HUMMER70 suggestions):
Pro-Gold rifle lube applied sparingly to patch, run from breech to muzzle using boreguide, about 5 such patches, each run AT LEAST twice, pretty clean by the time I was done, this time I finished with a greased patch, instead of finishing with a non-greased patch. The idea was to leave a film of grease in the bore.

Benchrest technique, u-shape shim wooden contraption around skinny forend of cheap cheap plastic stock, running in Rock BR front rest, rear leather bag, smoothly running, very firm grip (pulling into shoulder pocket), 16X scope, held dead center on target with no discernible shake (rifle intentionally zeroed a bit high at 100 yards). Chrony this time with diffuser worked much better.

Shot Velocity POI
1 2902 3.5"up, 1"R
2 2848 3" up 1/2"R
3 2896 3.25"up, 1.25"R
4 2838 2.25"up, 0.75"R (no idea why)
5 2840 3" up 5/8" R


Really looks like Hummer70's idea is the key.

Shilen barrel is still headed my way!
 

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HUMMER70, help me out here.

I don't understand the science behind this. It obviously works but are we not treating the symptom and not the cause?

I leave my barrels oiled, the first thing I do on the range is to run patches through them to dry. If I don't dry the bore I get a flyer, exactly the opposite.

@ Docsleepy. Why do you run you case through the FL die three times? You are work hardening the brass, is that what you want?

I sorted your results according to velocity.

Shot No. Speed Vertical
4 2838 2.25"
5 2840 3.00"
2 2848 3.00"
3 2896 3.25"
1 2902 3.50"

Average speed 2865 fps
Std deviation +-32 fps

- Your vertical displacement is roughly consisent with your velocities.
- Your standard deviation is about twice what what it should be to be considered OK, not good. Forgetting for a moment your initial problem I believe you could reduce your vertical displacement significantly if you could get your speeds more consistent.
- Do you individually weigh each powder charge or do you rely on a powder dispenser?
 
Andrew Leigh said:
It obviously works but are we not treating the symptom and not the cause?
Click to expand...
This is my opinion exactly.

Lots of methods to "work around" problems. I'm a fan of solving them outright. I have enough to keep track of. I certainly don't want to keep track of a regimen that a certain rifle likes in order to produce accurate results.
 
I've had problems with annealing. I don't have a fancy machine to do it, I do it by hand. So I intentionally work harden the necks a bit to try to hopefully bring them to a happy medium. I doubt that the work hardening they get from hand hand pressing is anything close to what happens when they get hit by 50,000 PSI And stretched to meet the neck walls of the chamber. But I could be wrong!

If you have any brilliant ideas to decrease my velocity dispersion I'd be happy to hear them! I use a Lee perfect powder thrower, and typically am within .1 grains. But this is Varget, and it doesn't meter perfectly. I have a charge master, but it is somewhat slower, and I haven't seen much of a difference in the past.

Shot number four still doesn't make any sense. Only 2 ft./s can't make that much difference. I'm guessing it has something to do with the particular hold on the rifle for that shot.
 
Before I annealed the zero would consistently change from week to week to week as the neck hardness changed. Annealing brought a significant improvement. Remember this is an $85 barrel.
 
docsleepy said:
I've had problems with annealing. I don't have a fancy machine to do it, I do it by hand. So I intentionally work harden the necks a bit to try to hopefully bring them to a happy medium. I doubt that the work hardening they get from hand hand pressing is anything close to what happens when they get hit by 50,000 PSI And stretched to meet the neck walls of the chamber. But I could be wrong!

If you have any brilliant ideas to decrease my velocity dispersion I'd be happy to hear them! I use a Lee perfect powder thrower, and typically am within .1 grains. But this is Varget, and it doesn't meter perfectly. I have a charge master, but it is somewhat slower, and I haven't seen much of a difference in the past.

Shot number four still doesn't make any sense. Only 2 ft./s can't make that much difference. I'm guessing it has something to do with the particular hold on the rifle for that shot.
Click to expand...

Hi Docsleepy,

moving away from the first shot flying.

OK I understand what you are trying to achieve on the case hardening, I do think that you will battle to control the consistency and therefore neck tensions could differ significantly. This will impact on accuracy and bullet speeds. Is there any way you can duplicate your shooting exercise with brand new cases to remove most the variability of neck tension?

Throwing to 0.1gr is fine and you can't see the difference at 100yds. Checked the Sierra software and you are close with your load vs. speed. Sierra also shows that you have an effective zero on the rifle at 260 yards to get 3" high at 100yds.

The shot with 2fps difference in vertical the could be the shooter, I have experienced similar.

Have you considered a different bullet weight? Some bullets weight simply don't agree with the rifle. My 30-06 shoots a 165 better than a 180 although I still load 180's for hunting.

When load developing I get a couple of patterns that can present, one is vertcal dispersion, the other is lateral dispersion and as I get closer to the perfect load the pattern become more random and triangular (use three shots for development). Is there a chance that your load may not be fully developed?

You only have a lateral dispersion of 0.75" which is great. So if you barrel was shot out how come it only affects performance in the vertical plane?

So theoretically the factors that give varying vertical displacement are;
- Erratic firing pin strike (weak / broken spring) you have discounted this already.
- Front rest being too hard, you have discounted this already.
- Variable loads, discounted at .1gr difference.

That leaves possibly
- Bullet weight not perfectly suitable
- Varying neck tension
- Breathing control
- Load not on an accuracy node.

Unfortunately I have no brilliant ideas but this is what I would do. Either nothing and wait for the new barrel and hope that sorts the matter out or;
- Get some brand new brass
- Do the Dan Newberry's OCW development routine and ensure that your load with new brass is correct and on an accuracy node.
- Once the load is established then conduct your cold firing routine with and without grease.

Good luck in your pursuits.
 
Andrew Leigh said:
Hi Docsleepy,

moving away from the first shot flying.

OK I understand what you are trying to achieve on the case hardening, I do think that you will battle to control the consistency and therefore neck tensions could differ significantly. This will impact on accuracy and bullet speeds. Is there any way you can duplicate your shooting exercise with brand new cases to remove most the variability of neck tension?


Have you considered a different bullet weight? Some bullets weight simply don't agree with the rifle. My 30-06 shoots a 165 better than a 180 although I still load 180's for hunting.

When load developing I get a couple of patterns that can present, one is vertcal dispersion, the other is lateral dispersion and as I get closer to the perfect load the pattern become more random and triangular (use three shots for development). Is there a chance that your load may not be fully developed?

You only have a lateral dispersion of 0.75" which is great. So if you barrel was shot out how come it only affects performance in the vertical plane?

So theoretically the factors that give varying vertical displacement are;
- Erratic firing pin strike (weak / broken spring) you have discounted this already.
- Front rest being too hard, you have discounted this already.
- Variable loads, discounted at .1gr difference.

That leaves possibly
- Bullet weight not perfectly suitable
- Varying neck tension
- Breathing control
- Load not on an accuracy node.

Unfortunately I have no brilliant ideas but this is what I would do. Either nothing and wait for the new barrel and hope that sorts the matter out or;
- Get some brand new brass
- Do the Dan Newberry's OCW development routine and ensure that your load with new brass is correct and on an accuracy node.
- Once the load is established then conduct your cold firing routine with and without grease.

Good luck in your pursuits.
Click to expand...

1. At present, all things ammunition are in short supply in the U.S. New match Hornady .308 cases aren't in stock where I've checked (I neck down to 7mm to obtain a tighter fit). I have some one-fired Remingtons that I might press 5-10 into service to give your theory a test.
2. I've done the ladder thing to the tune of several hundred bullets in the past on some rifles without ever reaching a REPEATABLE effect. Chance favors drawing incorrect conclusions I fear. Hence I just picked a bullet weight and haven't really investigated powder. Might be worth some effort.
3. I'm just very impressed that this $85 barrel is now shooting in the MOA range! even the first shot! (in 2 of three cold-bore tests so far).
4. I have seen velocity numbers before that are just amazingly consistent. So far, I haven't been able to do that....maybe I should try a benchrest or magnum primer, dunno. I believe I have some magnum LR primers, but beyond that....nothing is available in the U.S.
 
I think the culprit here is your reloading technique.

You're totally over-working your brass. Being a new gun owner, I imagine you're even a newer handloader.

I don't think it's the rifle so much as your handloading process.

Are you measuring your catridge OAL? Are they consistent? There's something quite wrong here if you're getting velocity spreads that wide.
 
BullfrogKen said:
I think the culprit here is your reloading technique.

You're totally over-working your brass. Being a new gun owner, I imagine you're even a newer handloader.

I don't think it's the rifle so much as your handloading process.

Are you measuring your catridge OAL? Are they consistent? There's something quite wrong here if you're getting velocity spreads that wide.
Click to expand...

One. Well maybe you're right that I'm overworking the brass. I can certainly try switching to the more normal technique after annealing. I'm pretty sure that I've tried it also in the past, but no harm in trying it again.

Two. I'm not sure why I am a new reloader? I reload seven calibers, and have probably done five or 6000 reloads by now. I'm getting groups under an inch with my reloads for a Mosin-Nagant; 6ppc groups using a homemade rifle down into the 3's

Three. I'm not sure why I am a new firearms owner? It is true that I did not have any firearms until after the election of 2008. However at this point I fill multiple safes. This particular gun, Was a sporter .223 that i rebarreled (just a thou or so over the minimum of the go-gage) and switched out the bolt head.


But I was completely perplexed by this high first shot problem and so came here to learn more. I'll certainly give your ideas a try!
 
Oh, and on the cartridge overall length: I have tried to keep these within a couple thousandths . I am a few thousandths off of jammed into the lands. Several different experiments suggested this was the optimum point.

The next chance I get, I'll reload some new brass, and I might learn something very important! Already, the grease tip seems to have made a huge improvement!
 
http://www.snipercentral.com/matchammo.htm

Since I don't know a whole lot about velocities, I looked at this article on the measured velocity and extreme spread of commercial match ammunition. I'm certainly not in the best of this group, but I appeared to be even with some of them. There seems to be an impact of the rifle chamber, and I'm dealing with a very very cheap barrel. Unfortunately, my brass has differing numbers of usages, and probably ranges from 5 to 15.
 
Hi Docsleepy,

the ladder method and the OCW method are quiet different but both effective.

To effectly use the ladder method one have a target out at about 600m for results to truely show as the method relies on vertical displacement only. The OCW method does not rely of vertical displacement but rather group pattern and size, triangulating the group and the POI.

It normally takes me around 30 rounds to fully develope a load from scratch. I have placed the method into spreadsheet format. If you are interested PM me you mail address and I will forward it.
 
doc, buying a whole bunch of guns in a hurry does not buy you the experience that comes along with them.


Having velocity spreads that wide would be totally unacceptable for my handloads. Before I did any other thing I'd find out what my loads were so inconsistent.
 
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