neck tension, vertical
- Thread starter skeetlee
- Start date
A
abintx
Guest
Pulled these notes from my Gene Beggs folder in my Benchrest file:
"TUNING OUT HORIZONTAL & VERTICAL DISPERSION
Most of my shooting during the past several years has been in the wind free environment of the tunnel. One thing that continues to repeat with every gun, barrel and bullet combination I have worked with is that
horizontal dispersion results from bullets being seated too far into the lands
vertical dispersion is the result of the powder charge being either too hot or too light.
Daryl Loker told me years ago that you tune out horizontal with neck tension and bullet seating depth,
tune the vertical out with the load. (Or in recent years since the advent of tuners, with the tuner.)
I assure you, if I put my standard load of powder in and seat the bullets on hard jam, I'll have two bullet holes of built in horizontal, and that's in a tunnel with no wind!
Pushing bullets back into the case .005 at a time, and the horizontal will disappear just when the bullets come off the lands or just kissing.
You might as well keep this to yourself after you see it with your own eyes because no one will believe you if you try to tell them; it goes completely against conventional wisdom.
Gene Beggs"
Hope this helps.
E
Eric K
Guest
Hi Skeetlee,
This is my real world experience in registered 1000 yard matches. I shoot a 6.5x47 lapua 293 no turn chamber. I shave off the high spots on the case neck for a total chamber clearance 0f 2895. Using a redding FL die with 287 bushing and neck sizing 90% of the neck i get 6 inches of vertical for 10 shots. I switched to a 288 wilson neck sizing die and sized only the first third of the neck and my vertical went to 12 inches. In my case I witnessed a large amount of vertical difference with the lighter neck tension.
Eric K
This is my real world experience in registered 1000 yard matches. I shoot a 6.5x47 lapua 293 no turn chamber. I shave off the high spots on the case neck for a total chamber clearance 0f 2895. Using a redding FL die with 287 bushing and neck sizing 90% of the neck i get 6 inches of vertical for 10 shots. I switched to a 288 wilson neck sizing die and sized only the first third of the neck and my vertical went to 12 inches. In my case I witnessed a large amount of vertical difference with the lighter neck tension.
Eric K
Eric,
You need to get up with Phil Bower (used to shoot at The Original Pennsylvaina 1,000 Yard Benchrest Club). He set 1,000 yard records firing cases with split necks. Probably didn't have even tension...
The reality, imsltho, is different things show a significant variance in different setups. You have to test. To avoid testing, just follow the recipe approach. You'll do 10 things (out of, say, 15) that don't matter, but it's easier than testing. One way or another, you "pay" for information.
You need to get up with Phil Bower (used to shoot at The Original Pennsylvaina 1,000 Yard Benchrest Club). He set 1,000 yard records firing cases with split necks. Probably didn't have even tension...
The reality, imsltho, is different things show a significant variance in different setups. You have to test. To avoid testing, just follow the recipe approach. You'll do 10 things (out of, say, 15) that don't matter, but it's easier than testing. One way or another, you "pay" for information.
I dont think i am having any neck tension problems. I was hoping, but after this morning and shooting with some different bushings, neck tension isnt it. To be quite honest, i am out of ideas why i am having such a vertical problem?? Im talking 100 200 yards here, not 600 or farther. Maybe its the barrel, or maybe its the extreamly light conditions while shooting between the 12' tall corn?? I just dont know yet. My bags and rest are proven, so i dont think there is any merit there. The pattern on my crown isnt quite uniform, so i am going to re cut sometime this weekend. I tyied a heavier spring in my action as well. no difference! Perhaps i just have a lemon barrel here??? Almost out of ideas, Lee
Lee,
you've mentioned several of the usual culprits that i've found when trying to eliminate the a vertical issue.
what i've seen with bad barrels, and that's all i've had for the last 2 or 3 years until recently, is that i generally won't have just a vertical problem. the barrels seem to send shots in some random direction from the group.
if your have purely vertical problems, that make me think it may be something other than a bad barrel.
YMMV.
what powder are you using?
how much vertical are we talking about? any pics of groups?
you've mentioned several of the usual culprits that i've found when trying to eliminate the a vertical issue.
what i've seen with bad barrels, and that's all i've had for the last 2 or 3 years until recently, is that i generally won't have just a vertical problem. the barrels seem to send shots in some random direction from the group.
if your have purely vertical problems, that make me think it may be something other than a bad barrel.
YMMV.
what powder are you using?
how much vertical are we talking about? any pics of groups?
Is there a pattern to the barrel throwing shot?
Hint -- the first group if the day is good, sometimes very good. Then it starts to get worse. If that's the case, or the exact opposite -- re-stress relieving the barrel, with heat, not Cryo, may give a cure. The "good" may not be quite as great, but the average will be consistent, and often OK. Seen it happen...
Hint -- the first group if the day is good, sometimes very good. Then it starts to get worse. If that's the case, or the exact opposite -- re-stress relieving the barrel, with heat, not Cryo, may give a cure. The "good" may not be quite as great, but the average will be consistent, and often OK. Seen it happen...
charles
You may be on to something there. When i was forming my brass i noticed fantastic groups. i thought for sure this barrel was going to be one to charish. I would only shoot 2 or 3 shots when forming then clean. The first group out of all testing i have done to try and figure this barrel out, was the better group. Vertical and tossing shots soon after.
I havent ever sent a barrel back, but i think this one will have to be sent back. I hope they can find something and get me fixed up. This kind of stuff is hard on a 2 or 3 barrel a year budget. I will say, i havent ever had any complaints with this particular barrel maker, so i guess my average is still pretty good. thanks, Lee
You may be on to something there. When i was forming my brass i noticed fantastic groups. i thought for sure this barrel was going to be one to charish. I would only shoot 2 or 3 shots when forming then clean. The first group out of all testing i have done to try and figure this barrel out, was the better group. Vertical and tossing shots soon after.
I havent ever sent a barrel back, but i think this one will have to be sent back. I hope they can find something and get me fixed up. This kind of stuff is hard on a 2 or 3 barrel a year budget. I will say, i havent ever had any complaints with this particular barrel maker, so i guess my average is still pretty good. thanks, Lee
DeltaBravo
Member
abintx,
Do you have any info on whether the horizontal dispersion is consistently left/right, based on twist, or just random?
Thanks.
Dennis
Do you have any info on whether the horizontal dispersion is consistently left/right, based on twist, or just random?
Thanks.
Dennis
M
max.burgess
Guest
annealing necks
Does annealing necks affect vertical any ? Thanks Max
Does annealing necks affect vertical any ? Thanks Max
joe
i tried that too. I may have already mentioned this but when i put my 22ppc barrel on the rifle the groups looked a little better, with just a couple flyers. Most of the groups looked really well. This got me to thinking that maybe the lack of recoil was the reason for the better groups?? I am going to go back out this evening after the rain and take a closer look at my scope rings, and double check that verything is tight. The hole recoil thing hit me today while i was at work. Might not be anything to it, but we will see.
I did have a small issue while mounting the scope rings on the front mount. One screw didnt feel quite right. Everything tightened up ok, or at least i didnt see any real reason to worry at the time i put them on. Do you think a loose screw or a bottomed out screw on a one piece ring could cause a vertical issue? I think it may be plausable?? Lee
i tried that too. I may have already mentioned this but when i put my 22ppc barrel on the rifle the groups looked a little better, with just a couple flyers. Most of the groups looked really well. This got me to thinking that maybe the lack of recoil was the reason for the better groups?? I am going to go back out this evening after the rain and take a closer look at my scope rings, and double check that verything is tight. The hole recoil thing hit me today while i was at work. Might not be anything to it, but we will see.
I did have a small issue while mounting the scope rings on the front mount. One screw didnt feel quite right. Everything tightened up ok, or at least i didnt see any real reason to worry at the time i put them on. Do you think a loose screw or a bottomed out screw on a one piece ring could cause a vertical issue? I think it may be plausable?? Lee
Oh yes loose scopes will give you everything you don't want! Check everyone of the screws from the base up, leave nothing to chance. Have seen this scope problem make many a grown man cry. And while you're at it, change scopes. I know you said you put the other barrel on, but you also said you still are getting a couple of flyers. Maybe you're getting old and afraid of a little recoil?
Joe Salt
Joe Salt
Boyd Allen
Active member
Charles,
On your re stress relieving idea. I am aware of a couple of examples where this was the case. One as a sketchy story, and the other that I have a lot of details on. Have you run across examples of re heat treating that worked. In the case where I have details, literally the first five shots from a cold rifle were just fine, and after that the groups became significantly larger. A "nitrogen soak" (re stress relieving with heat, in a nitrogen atmosphere) followed by a light work over with a ball hone fixed the problem.
Boyd
On your re stress relieving idea. I am aware of a couple of examples where this was the case. One as a sketchy story, and the other that I have a lot of details on. Have you run across examples of re heat treating that worked. In the case where I have details, literally the first five shots from a cold rifle were just fine, and after that the groups became significantly larger. A "nitrogen soak" (re stress relieving with heat, in a nitrogen atmosphere) followed by a light work over with a ball hone fixed the problem.
Boyd
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I'm about the same, Boyd. I know of one (mine), was told of another, and read about yet another in the old P.S. I think it was an article reviewing the then-new Viper action, guy was swapping barrels between a Viper & Panda...
With mine, I shot the smallest group I've ever shot in a sanctioned match outdoors -- .082. It was always small for Match 1, and in the 3s by Match 3. Tried various bullets & powder. I even had someone else shoot it on a practice day, to make sure it wasn't me.
I considered trying to fabricate something like Jerry Hensler use to use -- a pump/flush system with Kerosene between matches to clean & for this barrel, also to cool. Never tried it -- in the end, I just sent it back. While I don't know all the details, it was re-heat treated (not Cryo'd), and it then settled into an honest lower-2s barrel.
With mine, I shot the smallest group I've ever shot in a sanctioned match outdoors -- .082. It was always small for Match 1, and in the 3s by Match 3. Tried various bullets & powder. I even had someone else shoot it on a practice day, to make sure it wasn't me.
I considered trying to fabricate something like Jerry Hensler use to use -- a pump/flush system with Kerosene between matches to clean & for this barrel, also to cool. Never tried it -- in the end, I just sent it back. While I don't know all the details, it was re-heat treated (not Cryo'd), and it then settled into an honest lower-2s barrel.
N
ncnbrsa
Guest
It is my guess that the action is loose in the stock.