Horizontal Stringing

[Goin'Hot]

I really don't know where to put this thread. I'm going to presume it's a load issue with 2 different rifles. Here it goes...

I went out at 200 yards to test some loads and see what would happen with seating depth changes. The first picture was shot "round robin". I would shoot one round that was 0.005" off the lands and then progress until I had shot all 4 loads ending at 0.020". I adheared to a 2 minute shot interval. The next round was shot from right to left etc...

Between 4 shot stings, I would shoot groups with the 260 (which we'll get in to next). Here's the results with the first rifle.

The issue I have is the horizontal stringing in the first group shown which is 0.005" off the lands. Vertical C-C is less than 0.5". All the other groups look "similar" although terrible.

My 260 has 2 group that show similar results on groups #5 & 6. The groups were shot left to right, 5 shots at a time with ~10 seconds between shots. I varied charge weight and OAL on these groups but when the vertical went away, the horizontal gets excessive.

Vertical on #6 (C-C) is ~0.16", Horizontal (C-C) ~1.6".

Since the groups in the first pic were shot round robin, and the groups in the 2nd pic were shot in "groups", I know that wind is not the issue. Anybody care to tell me what's going on here and where I need to go for correction?

 

[gcoulsey]

Re: Horizontal Stringing

IME horizontal stringing is usually me goofing the shots.
Either poor trigger control or position behind the rifle.

Load up and re-test those particular groups to confirm.

 

[MALLARD]

Re: Horizontal Stringing

nice post

Both round robin and not round robin tests suggest like you mentioned , that the horizontal groups are out of your (trigger)control.

i think it's the harmonics of your gun. I couldn't explain it any better then that.

I have a tuner , when i adjust it I can create vertical groups, or horizontal groups... or groups that have both horizontal and vertical depending on the tuners setting.

 

[Goin'Hot]

Re: Horizontal Stringing

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gfunkUK</div><div class="ubbcode-body">IME horizontal stringing is usually me goofing the shots.
Either poor trigger control or position behind the rifle.</div></div>
The 2 rifles are shot entirely different and yet show the similar results in different groups. The 260 is mag fed and burns 1/2 the power and 60% of the payload so, I can keep my cheekweld to the rifle and rack off the 5 shots without having to worry about the "excessive heat" of sending 5 down range in less than 3 minutes. The rifle shot in the 1st pic is a single shot and develops quite a bit more heat energy so I shoot and take time for the remaining shots. This is how the rifle will actually be shot so, I try and duplicate the conditions when working up a load.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MALLARD</div><div class="ubbcode-body">nice post

Both round robin and not round robin tests suggest like you mentioned , that the horizontal groups are out of your (trigger)control.

<span style="color: #3333FF">i think it's the harmonics of your gun</span>. I couldn't explain it any better then that.

I have a tuner , when i adjust it I can create vertical groups, or horizontal groups... or groups that have both horizontal and vertical depending on the tuners setting.</div></div>
That's what i think as well. I was wondering where to go from here. Is this a "seating depth" or a "powder charge" issue or is there no such logic or data to pull from? I'd really like to stay off of the lands.

The vertical is great but, when I miss, was it the wind or my load? Did I pull the shot or............

 

[stranded]

Re: Horizontal Stringing

What is your brass prep like? I have found that case volume differences can cause gouping like that for me.(three together two different)

 

[Goin'Hot]

Re: Horizontal Stringing

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Stranded</div><div class="ubbcode-body">What is your brass prep like? I have found that case volume differences can cause gouping like that for me.(three together two different) </div></div>

For the top picture, all cases weighed within 0.8 gr of each other. Neck turned (twice), trimmed, annealed, primer pockets uniformed and cleaned. Just for this testing purpose, I also measured bullets from ogive to base. Each 5 bullet set was within 0.0015" of each other. Powder was "thrown" on a chargemaster and then weighed on a beam scale.

For the bottom picture, the brass was neck turned, trimmed, primer pockets cleaned, bushing sized and loaded. No "special care" was taken for brass weight or bullet selection or powder weighing above letting the chargemaster throw it.

 

[Goin'Hot]

Re: Horizontal Stringing

Just for reference, I re-took the first photo and added dimes.

 

[Edo1]

Re: Horizontal Stringing

Have a known good shot, shoot the group for you. That would tell you if it's something you are doing.