Vertical Stringing off Bench

[ShtrRdy]

I'm having trouble shooting a 300 Win Mag off the bench. I'm seeing vertical stringing over 2" at 200 yd. My horizontal spread is less than 1/2". If I shoot a lower recoiling rifle I don't see this result. I'm pretty sure it has something to do with me tensing up more or less when I release the shot.

I have a muzzle brake on the gun, but is there anything else I can do to work through this? I'm trying to relax when I make the shot, while pulling the stock into my shoulder pocket, but I can feel tension building. I'm shooting off a front rest, (not bipod), and a rear bag.

Thanks, Todd

 

[Dkindels]

Are you reloading? vertical stringing can sometimes mean your velocity isn't just right for the rifle. Run the ladder test?

 

[Willys46]

Inconsistent shoulder pressure gets me from the bench. Especially with bigger guns.

Do you see the same vertical shooting prone?

 

[TheGerman]

Chrono your rounds. If you see that the muzzle velocity has a large standard deviation in a string of 5 or 10, thats your issue.

 

[ShtrRdy]

These are reloads but I don't think it's velocity. I ran some numbers through JBM Ballistics and I would have to have about 330 fps spread in my velocity to get a vertical impact spread of 2" at 200 yds.

I haven't tried shooting it prone. I'm more stable shooting off the bench but I may be applying different shoulder pressures.

My impacts are from 1" above point of aim and 1" below point of aim. I didn't pay close attention to which shot went where but I don't think it's heating up and shifting. I could be wrong and I'll keep a closer watch.

The scope I'm using on this rifle is only a 9 power without parallax adjustment, so parallax error might be some/all of the problem too.

Thanks for the suggestions. - Todd

 

[Cncjerry]

I just posted the same problem in the reloading section.

I also shoot a 300 win mag off the bench without a brake. I chrono all my rounds, very close in std deviation, small ES, etc, etc. Played with loads etc, etc. Still get vertical, driving me crazy.

I am going to the range on Wednesday to see if the solution works, but all indications are that it is related to pulling the stock too hard into your shoulder to reduce recoil. Diagonal stringing I was told was related to increasing shoulder pressure as you pull the trigger, maybe subconsciously, again a shooting technique defect related to anticipating the heavy recoil. I solved the diagonal problem with consistent shoulder pressure, now I need to lighten-up on the shoulder weld in general. This makes sense as if you are pulling into the shoulder, the barrel will have more of a tendency to lift as recoil starts.

This makes even more sense as I have been known to screw-up the money shot, where I get the first three or four in nearly the same hole, maybe .25moa at 100yds, and the 5th goes high. Could have something to do with pulling the gun in closer to firm things up for the last shot?

The chrono on this one shooting 168 AMAX with 78gr H1000 and mag primers:

2,904
2,917
2,936
2,930
2,930

for a std dev of 12.9, not my most consistent, but o.k. as these were unfired, full-length sized, new brass.

Alternatively, it could also be related to inconsistent eye relief but I think the shoulder pressure is the culprit as I have a process that gets me to the same eye relief.

Let me know if you get anywhere, good luck.

 

[Cncjerry]

Here's another example where I relaxed after shots 1,2 so 3 went in the hole, then tight for 4 and relaxed for 5.

Chrono was on the sheet:

2,949
2,923
2,923
2,917
2,917

for std dev of 12.6.

 

[NateB]

Could be as simple as breathing control

 

[Easy_E]

Check your rest to see if your front sling mount is catching under recoil if you have one ? It's a simple thing but I was having trouble one day and never caught it .

 

[Sterling Shooter]

All,

Vertical dispersion shows:

1. Poor follow through
2. Changing sight picture
3. A very low position
4. Changing sight alignment
5. Failure to maintain proper eye/sight alignment
6. Changing distance from eye to sight
7. Varying the rifle butt position in the shoulder
8. Position of the left elbow wrong
9. Not enough head pressure

 

[Nishgriff]

All,

Vertical dispersion shows:

1. Poor follow through
2. Changing sight picture
3. A very low position
4. Changing sight alignment
5. Failure to maintain proper eye/sight alignment
6. Changing distance from eye to sight
7. Varying the rifle butt position in the shoulder
8. Position of the left elbow wrong
9. Not enough head pressure

Good checklist, thank you. I will print this and take it to the range with me!

 

[ShtrRdy]

All,

Vertical dispersion shows:

1. Poor follow through
2. Changing sight picture
3. A very low position
4. Changing sight alignment
5. Failure to maintain proper eye/sight alignment
6. Changing distance from eye to sight
7. Varying the rifle butt position in the shoulder
8. Position of the left elbow wrong
9. Not enough head pressure

Thanks for the list of possibilities. I've probably got several of these affecting me.

 

[Fred @ Bison Tactical]

Nishgriff -- I was thinking about you reading this thread -- glad you saw it also !!

 

[Nishgriff]

Nishgriff -- I was thinking about you reading this thread -- glad you saw it also !!

HA! Yeah, good to shoot with you yesterday.

 

[thefiremeister]

I just got back from the range and was having the same problem. I just put a Premier on my Savage and was going to do a little fundamentals practice before I got the good ammo out. Got on paper from the bore site and pretty close to zero with two more shots.

I started shooting some five round groups and every one had vertical stringing. I like to blame my equipment but with my current set up i can't.

I'm sure I have a few of these things going on. Just glad my horizontal was good and my sight picture was coming back after recoil.

Vertical dispersion shows:

1. Poor follow through
2. Changing sight picture
3. A very low position
4. Changing sight alignment
5. Failure to maintain proper eye/sight alignment
6. Changing distance from eye to sight
7. Varying the rifle butt position in the shoulder
8. Position of the left elbow wrong
9. Not enough head pressure

 

[creids98292]

Its not always a deviation in FPS, I've seen it where is a CUP issue. You can have a great load on the chrony but having vertical stringing. Going to a heavier charge (safely) mag primer or faster powder may be needed to get rid of the vertical. This is a great place to start for the rifle, then it can only be you
My solution is to increase in .3 grains till you get horizontal stringing then back the charge down to the best group, this will be your starting point for the ladder or node testing, which ever you prefer. Now you can bust out the chrony and graph your velocity loading to the center node. Everybody has "their" way for load development and I learned this way from a Australia F-class shooter and it works for me.

 

[James n TN]

Two things comes to mind here paralex is off on scope or you have too much sand in your front bag on your rest

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[Rem7targetactical]

I do believe somewhere on here in a thread, that a person found out his vertical stringing was due to a bad chamber reamer and after having his barrel reworked everything went away. Just thought I'd mention it. And if I'm not mistaken a rifle with loose action screws or one that isn't bedded properly can also cause vertical stringing?

 

[zenbiker]

I'll toss in here with this hard won bits of experience from the School of Hard Knocks:

1) Unless you're in extremely cold weather with very slow large grain powder, I have found Magnum Primers to be unnecessary in the 300 Win Mag. I use Fed 210Ms, even in my loads for 240 SMKs and a casefull of XMR3100, RL25, or Western Magnum. Magnum primers can pop the bullet out of the case neck into the leade before the powder really starts to burn, leading to different pressure curves (but seemingly identical MVs).

2) Try different seating depths. If your reamer/chamber allows it, go from just to touching to 0.010" off. Some WinMag chambers won't allow 185 grain projectiles to be seated out that far.

3) Be aware of your neck tension when seating the bullets during reloading. If there is wide variance from very little pressure to a firm press, this is where it will show up.

4) Take a piece of fired brass and try to slide a bullet into the neck. It should slide in smoothly without pressure; if it is tight or extremely loose, there is part of the problem.

5) Your rest. Others here have mentioned follow through. Pay attention to where the reticle ends up at the finish of recoil. You should see pretty much the same picture every time. For me, it's usually up and left. If you aren't seeing that and you are shooting off a bipod, well, there is another thing to look at.

Somedays, shooting almost makes me want to take up golf.

Almost. ; )

Sent from my iPad using Tapatalk HD

 

[OptedOut]

"Common" causes here;
CURES for VERTICAL STRINGING

 

[Deadshot2]

Its not always a deviation in FPS, I've seen it where is a CUP issue. You can have a great load on the chrony but having vertical stringing. Going to a heavier charge (safely) mag primer or faster powder may be needed to get rid of the vertical. This is a great place to start for the rifle, then it can only be you
My solution is to increase in .3 grains till you get horizontal stringing then back the charge down to the best group, this will be your starting point for the ladder or node testing, which ever you prefer. Now you can bust out the chrony and graph your velocity loading to the center node. Everybody has "their" way for load development and I learned this way from a Australia F-class shooter and it works for me.

Very true that everyone has a different method for load development. A local BR Shooter who recently posted a 400-17X at 300 yards uses the following method.

If he's getting "Vertical" he merely increases the powder charge. Keeps increasing until the vertical turns to a "triangle" (he uses 3-shot groups for workup) and then reduces the increments of added powder. For .308 he increases charges by .4-.5 gr at first and then goes down to .2gr increases until he gets "Single hole". When the next .2 gr increase goes back to the "triangle" he backs down to the middle of he best loads. Last adjustment is OAL for the fine tune.

The rest is all consistency in the shooter's actions.

 

[Angmo]

Could be a simple as consistent cheek placement on the stock. Watch your follow through. Don't jerk your head up after the shot.

 

[djskit]

Cause #6 is my vote.

 

[40xs]

It sounds like you have already touched on the problem in your original post. Heavy magnums are not easy guns to shoot. They require all you have to give in order to execute the perfect shot. Every shooter out there can not shoot magnum rifles like they can .22's. You have to be sort of a masochist, and love pain. LOL.

 

[Disturbed]

Inconsistent shoulder pressure gets me from the bench. Especially with bigger guns.

Do you see the same vertical shooting prone?

same here