Horizontal string: Need help to analyze targets

[Kevin1]

After an initial ladder testing at 300 yards, I settled on 43 to 43.2 grain of Varget with SMK 175.
I did my ladder testing with Lapua, but the below results are with Winchester brasses.

Load:
Winchester Brass
43.2 G of Varget
SMK 175
OAL 2.82 (a jump of -0.005, but this measurement could be approximate)

Rifle:
Savage 10FP 308 in B&C Medalist with SS 10X42 scope

Shooting from Harris bipod and rear sandbag.

Weather condition:
Variable wind from back of around 10 mph




The numbers in the circle is the sequence of grouping (sequence 1 would be the first grouping after cleaning)

200 yard:
Sequence 6: 1.37" (0.72 MOA)
300 yard:
Sequence 7: 2.76" (0.96 MOA). 4 shots in 1.17 " and horizontal string
Sequence 8: 1.92" (0.67 MOA)

500 yard:
Sequence 9: 7.4" (1.55 MOA). Horizontal string!


I'm not able to understand the reaction of this load at different distances.

Could this be the torque setting on my stock (for these targets I had set it to 50 in/lbs. I'm going to set it to 65 in/lbs for next time).


200 and 300 yard targets


500 yard target

 

[Hi Speed]

Re: Horizontal string: Need help to analyze target

the 500 yard target has horizontal stringing and the 200 and 300 are all over the place. If you are shooting from a brick solid rest I would say your gun doesn't like the load as much as you thought it did at first. Have you considered a different charge. If you are positive the load is GTG and your rest was GTG then I would have to say this looks like a trigger control issue to me. Especially the 500yarder, but that's my military mind speaking. Wind can start playing tricks at that range too. What rest were you using. What were weather conditions. What type of groups was this load shooting @100yds. We'll go from there.

That is not bad shooting not knowing too much about your shooting history.

 

[Kevin1]

Re: Horizontal string: Need help to analyze target

I edited the original post to add that I was shooting from a bipod with rear rest.

I did my ladder testing at 300 yards and the horizontal spread already existed. But from what I understood, what counts for a ladder testing is only the vertical spread.

My target at 500 yards and one of the target at 300 yards confirms that vertical variation is very minimal (especially the one at 500 yards). I can't explain my second 300 yard target though....

I only tested this load at the targets that you see.

 

[Hi Speed]

Re: Horizontal string: Need help to analyze target

I think you'll find an accuracy node lower in the charge weight. Go there and find glory. Mine likes 44.6 FWIW so going up might ball park you. Was it windy at all? Was your rest a bag? Yes it was.

 

[Kevin1]

Re: Horizontal string: Need help to analyze target

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hi Speed</div><div class="ubbcode-body"> I think you'll find an accuracy node lower in the charge weight. Go there and find glory. Mine likes 44.6 FWIW so going up might ball park you. Was it windy at all? Was your rest a bag? Yes it was. </div></div>

Yes it was windy (variable from back around 10 mph).
I want to get ideas of what I can correct before my next trip to the range.

My other accuracy node is around 41g of Varget and it gives me consistent grouping with an average of 0.59 MOA at 100 yards.

So you don't think that playing with OAL could improve this and I better go back to 41 G.

Also keep in mind the torque I had on my stock (50 in/lbs)instead of the recommended 60 to 65.

 

[XTR]

Re: Horizontal string: Need help to analyze target

I'd bet this is an Indian not an arrow problem. I'm sure there some folks to give better answers but one that I've straightened out in the last yr is cheek weld, it's pretty easy to push left and right.

Mostly, I'm betting wind. Ten MPH is a fair amount of wind. Behind and right or left or switching and you'd easily toss some wide. I'm guessing your MV to be in the 2650 range. At 500yds a wind value of only <span style="text-decoration: underline">1mph</span> pushes you 2+ inches, that's very easy to have happen esp if you didn't have wind flags out. That 2 inches becomes 4 inches of movement if you've dialed it in and you get a switch. (At 600 yds I shot two 9s in a row in practice a couple of weeks ago purely because I missed a lift. I dialed it and shot an X I shot then proceeded to shoot another 9 out the other side when I didn't believe the let-off. )

 

[Hi Speed]

Re: Horizontal string: Need help to analyze target

XTR is on to something here. When testing loads there needs to be as little of you in the equation as possible. Otherwise your'e testing you and the load. You can't do both at the same time. The 500yd target has one of these two conditions or both. Trigger control/constant pressure cheek weld and wind.

a good load in my savage measures about the same at 200 as it does at 100. Three hundred plus and mother nature starts in with her .02.

 

[Kevin1]

Re: Horizontal string: Need help to analyze target

It totally makes sense that the vertical strings are due to wind. What doesn’t make sense is my 200 yard and one of my 300 yard targets that are not that good and I don’t think it’s the shooter.

 

[Kevin1]

Re: Horizontal string: Need help to analyze target

This is a reading on grouping diagnosis
http://www.rifleman.org.uk/Fuller_group_diagnosis.htm

The vertical string is on fig III and according to the article it’s because of “Faulty bedding. The group may be at any angle, with one end more heavily loaded than the other.”
This sort of confirms the suspicions I had about the torque on my stock (50 in/lbs instead of the recommended 65). But now, even though it doesn’t make sense to me, I’m also wondering if it could be because of my cheap powder measure (Lee Perfect Powder Measure).

 

[targaflorio]

Re: Horizontal string: Need help to analyze target

Did you adjust parallax for each distance?

 

[Kevin1]

Re: Horizontal string: Need help to analyze target

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: targaflorio</div><div class="ubbcode-body">Did you adjust parallax for each distance?</div></div>

I tried... I sort of left it at +/- 500Y as I wasn't seeing much difference between 300 to 500 y. I made sure that when I move my head the reticule is not moving (not that much at least). Since it's a 10X fix power scope and I wasn't that much concerned with the parallax. But it's definitely something I will pay closer attention next time.

 

[DCR]

Re: Horizontal string: Need help to analyze target

This probably isn't the answer but it's something I found with my B&C. Check the barrel channel and barrel for contact. Mine was contacting in 2 different places on my R700. Blatent paint marks on the barrel and rub marks in the barrel channel. I believe due to the thick paint coating they put in there. The paint is also applied to the aluminum bedding block a smidge at the front and rear. Make sure it's sanded out of the channel and the aluminum block front and rear.

 

[WhiskeyWebber]

Re: Horizontal string: Need help to analyze target

The horizontal stringing looks like a very consistent error in not pulling the trigger straight back. I don't know what order you shot these in because that would tell a story too but I would say the good news is your breathing and powder charge are spot on from shot to shot.

The picture @ 300 that shows you dancing all around the center looks like parallax to me. I've seen parallax show up as a triangle with a three shot group. I don't know what order you shot those in but I can make out a triangle or two. Sometimes you have to have the target slightly blurred to get the reticle to stop moving when you do the head move check.

On position, did you shoot all of these groups without breaking your position? If yes, it could be also be a combination of your position drifting with recoil and then your trigger finger angle changing a bit after each shot to compensate. One way to check is to stand up and rebuild your position after each shot and see of the groups change.

Those are nice groups for those ranges! The adjustments you make at this stage will be very fine.

 

[Kevin1]

Re: Horizontal string: Need help to analyze target

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body">The horizontal stringing looks like a very consistent error in not pulling the trigger straight back. I don't know what order you shot these in because that would tell a story too but I would say the good news is your breathing and powder charge are spot on from shot to shot.

The picture @ 300 that shows you dancing all around the center looks like parallax to me. I've seen parallax show up as a triangle with a three shot group. I don't know what order you shot those in but I can make out a triangle or two. Sometimes you have to have the target slightly blurred to get the reticle to stop moving when you do the head move check.

On position, did you shoot all of these groups without breaking your position? If yes, it could be also be a combination of your position drifting with recoil and then your trigger finger angle changing a bit after each shot to compensate. One way to check is to stand up and rebuild your position after each shot and see of the groups change.

Those are nice groups for those ranges! The adjustments you make at this stage will be very fine. </div></div>


Thanks. This is really useful. I know what I need to work on next time:

- Trigger pull: I never paid that much attention on having a straight trigger pull.
- Parallax: I always used the parallax setting as a side focus. The fact that sometimes the actual target could slightly be blur to get the right parallax is eye opening (if I may

) to me.
BTW the order I shot is the sequence I’m mentioning in the initial post and I did break my position between each shot.

 

[Goldbeachman]

Re: Horizontal string: Need help to analyze targets

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Kevin1</div><div class="ubbcode-body">
I did my ladder testing with Lapua, but the below results are with Winchester brasses.
</div></div>

To me, this is not good and I'm a little surprised no one commented on this yet in the thread. What is your ladder test with Lapua brass supposed to tell you in load development with your Winchester brass? So many variables can change from one lot of brass from manufacturer A to manufacturer B that the ladder test with Lapua brass is not valid with your Win brass.


Be that as it may, the 500 yard group shows very little vertical (appx. 1.5 inches only) but significant horizontal stringing. The comments about trigger, wind, and parallax are dead on, imho. Throwing in the issue you raise about the torque on the stock screws and taking your head off the stock in between shots, I'd say another go at it is justified.


It would be interesting to see what your Lapua brass at the preferred ladder test charge weight will do at distance. Also, doing a ladder with your Winchester brass and then going back to that brass lot for distance testing (meanwhile squaring away the stock torque and technique issues mentioned) would be my suggestion.

Sorry if you have a day job because this can be a lot of work (worth it though).

Good luck!

 

[Kevin1]

Re: Horizontal string: Need help to analyze targets

All,
Thanks for your input.

There was another major problem I just realized. I'm using Lee Perfect Powder Measure and was not measuring individual charges. This leads to some variation in powder throw(I estimate it to be around 0.3g). From what I've read on this site there is no other way than measuring each throw.

So now I'm measuring the powder charge for each bullet....And it's sooo time consuming (it took me like 45mn to throw powder and sit bullets for 20 rounds!!)

I usually shoot 100+ rounds every time I go to the range. I'll probably have to reduce that number. Hopefully this will help keeping a higher level of concentration.

 

[WhiskeyWebber]

Re: Horizontal string: Need help to analyze targets

That vertical is even more amazing knowing that you had a 2-3 g variation in each charge. I'd say you have found a very forgiving node with that load.

 

[Arbiter]

Re: Horizontal string: Need help to analyze targets

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Kevin1</div><div class="ubbcode-body">All,
Thanks for your input.

There was another major problem I just realized. I'm using Lee Perfect Powder Measure and was not measuring individual charges. This leads to lot of variation in powder throw(I estimate it to be around 2 to 3g). From what I've read on this site there is no other way than measuring each throw.

So now I'm measuring the powder charge for each bullet....And it's sooo time consuming (it took me like 45mn to throw powder and sit bullets for 20 rounds!!)

I usually shoot 100+ rounds every time I go to the range. I'll probably have to reduce that number. Hopefully this will help keeping a higher level of concentration.
</div></div>

Using a digital scale and weighing each charge will improve the consistency of your velocities, but it's not likely going to solve that horizontal problem, IMO. I did a quick test once with my Lee and found powder charges varying from 44.8 to 45.2 grains of Varget, when set to throw 45.0 even. I <span style="font-weight: bold">strongly</span> doubt that you're seeing an extreme spread of 3-4 <span style="font-weight: bold">grains</span> because of the Lee.

Pay attention to the wind, and focus on proper trigger pull. Don't go chasing wild leads that are going to reduce the amount of live fire practice you get, because that's exactly what you don't want to do if your goal is to improve.

 

[Kevin1]

Re: Horizontal string: Need help to analyze targets

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Arbiter</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Kevin1</div><div class="ubbcode-body">All,
Thanks for your input.

There was another major problem I just realized. I'm using Lee Perfect Powder Measure and was not measuring individual charges. This leads to lot of variation in powder throw(I estimate it to be around 2 to 3g). From what I've read on this site there is no other way than measuring each throw.

So now I'm measuring the powder charge for each bullet....And it's sooo time consuming (it took me like 45mn to throw powder and sit bullets for 20 rounds!!)

I usually shoot 100+ rounds every time I go to the range. I'll probably have to reduce that number. Hopefully this will help keeping a higher level of concentration.
</div></div>

Using a digital scale and weighing each charge will improve the consistency of your velocities, but it's not likely going to solve that horizontal problem, IMO. I did a quick test once with my Lee and found powder charges varying from 44.8 to 45.2 grains of Varget, when set to throw 45.0 even. I <span style="font-weight: bold">strongly</span> doubt that you're seeing an extreme spread of 3-4 <span style="font-weight: bold">grains</span> because of the Lee.

Pay attention to the wind, and focus on proper trigger pull. Don't go chasing wild leads that are going to reduce the amount of live fire practice you get, because that's exactly what you don't want to do if your goal is to improve.</div></div>

You're right. I've noticed around 0.3 g (and not 3g) of variation which your test confirms. I'll edit my initial post.