Horizontal stringing?

[hooligan1]

The rifle is a 700 bdl .243 win, not sure of twist.
Problem is it wont group 100 grain bullets with no less than 5 different powders, two different primers.
Finally I found a decent load with a 95 grn. Ballistic Tip, and IMR 7828,(45.2 grains to be exact) and the grouping was 2 inches wide, ( 5 rounds @ 100 yds) but all but one rnd were on the same horizontal plane.

Read this befoe you reply: Pillar bedded, freefloated, 4 lb trigger with little creep, Leupold bases and rings, (blue locktited and torqued) shooting off a lead sled, with 48 lbs of weight on the sled.
Some articles I have read say the groups with the least verticle deviation is actully what we want.... And as far as groups that I have tested goes this probably has the Very Least verticle deviation than loads I already covet.
Also there was a wind that day, but at my range it's pretty protected, enough I considered it a No-Value wind.

BTW, The flyer on the left is the very first shot of that group, and that was definetly me.

 

[Bart B.]

Here's what can cause that to happen....

Trigger finger's not pulling straight back on the trigger.

Way out of square case heads. Possibly caused by previously being fired in that rifle and it's got a way out of square bolt face.

Scope's windage adjustment's backlash spring is severly weakened.

One scope ring's not tight on its base; it moves a tiny bit side to side from recoil.

Does this situation repeat itself for several few shot groups?

 

[hooligan1]

Does this problem repeat itself for several few shot groups?
Well Bart B. I have had this one instance with a data load I was testing. It grouped consistantly enough that further testing this load will be done. I don't know that the trigger pull isn't the main bug here, as most of my rifles have nice triggers that are lighter with no creep than this one, but I've shot better groups with a worse trigger than this one,. No part of the scope is loose, unless it is internal, and that may be.
I also can dissect the load and the coal of this test load more, thought maybe it's a load issue. Caseheads are same as I fire from another rifle that shows no sign of problems.

And I haven't seen anything like this in my other rifles, (low verticle deviation/horizontal stringing)

 

[boondocker385]

I have had that problem once with pillar bedded. ....make sure it is tightened uniformly.

 

[boondocker385]

Sorry, baby was crying..lol. depending on who put the rifle together sometimes on of the screws is tightened before the other and it causes a minute amount of tension. A torque wrench should be used and each screw tightened in 2 lbs increments.

 

[cvc944]

Groups with stringing, either vertical or horizontal, can be the result of the shooter, the rifle, or the load, or a combination of any of these. If I'm sure my rifle is bedded properly, my scope is securely mounted, and I'm my normal self behind the trigger, I look at the load. I use the following to fine tune...

HORIZONTAL
Seat the bullets out farther toward the lands and/or reduce the powder charge.
VERTICAL
Seat the bullets deeper into the case and/or increase the powder charge.

I'm not sure I understand the 'least vertical deviation' being what we want. I myself would much rather cover my groups with a quarter than with a cigarette.

 

[Jimro]

cvc944,

Least vertical variation is a goal for competition shooters. If you know your loads are ALWAYS good for vertical then you can focus on the wind a bit more knowing that you round will always land "somewhere" along the horizontal line that you aimed at. Horizontal spread of the rings is greatest at their center, so if you are dead on vertically and your wind call is off, having your round impact on the same plane as the fattest portion of the X ring (and all subsequent rings of course) maximizes your chance for a better score.

I wouldn't bother working on least vertical spread for a hunting rifle.

Hooligan1,

I would try a scope swap first to eliminate that variable, it is relatively "quick and easy" to do.

If that doesn't work, bring an inch pound torque wrench and set your action screws to 45 on the rear and 55 in pounds on the front. Then increase the rear torque by 2 ft/lbs until you get the accuracy you want or you reach 55 inch pounds for the rear action screw.

Also, check your muzzle crown for concentricity.

Jimro

 

[hooligan1]

Jimro, the muzzle is excellent, but I'm thinking we're on the right track with stock torque as Bonndocker elated to... Also I have'nt adjusted COAL in this testing,, thinking maybe a combo....
I also think it likes lighter bullets,(maybe I haven't found the right charge with 100 grainers) because I have extensively tested the Sierra 100 grain Gamekings, with almost every powder I own...Wincester 780 Sup.,H 4350, IMR 4350, IMR 4831, Varget, H1000, IMR 7828, RL 22, H4831sc,.... I also experimented with magnum primers....
I hope it the stock torque as that's easyto remedy....and it's trigger is different than what I use most...

 

[xLPlushy]

Hooligan1:

Sounds like my dilemma with Hornady's 162gr SST's in my 7mmRM. I tried H4831 and H1000 to no avail. They either group vertically, diagonally, or horizontally. And nothing even worth duplicating. The best was 1.756" at 100yd. I have given up on that load for now, thinking that I haven't found the right powder/COL/charge weight to use with that bullet yet.

Still working on them 130gr Sierras. In my first round of testing I can cover a few of the groups with a nickel.

Have you put any other ammo thru this rifle aside from your own loads with the 95&100gr bullets? Does high quality factory ammo group similarly?

I had a similar issue 3 or so years ago when I bought a Bell&Carlson medalist stock and glass bedded and free floated it. Used a time tested load that would hold 3/8" at 100yd to try it out. Couldn't hold tighter than 4". Tried the stock torque and all, didn't change anything. Turns out, my rifle doesn't like to be bedded and free floated all fancy like. Went back to the factory stock and it still shoots like a dream.

 

[Kimber84]

Find out torque specs on the action screws and make sure they're tightened correctly.

 

[hooligan1]

I will retorque, and I loaded 15 more round and used a longer COAL, remembering that my old 700 loved bullets loaded right to the lands.

 

[hooligan1]

Recap

The fella that owns that rifle called me yesterday announcing that he'd shot a cloverleaf at 100 yds with it, guess the retorque and ammo adjustment worked, and it's probably because somebody else was behind the trigger!!

 

[Bart B.]

There's one thing that I believe is guaranteed to cause horizontal shot stringing with an otherwise very accurate rifle.

Sitting at a shooting bench holding a rifle against ones shoulder as it rests atop something (bags, rest, etc.) makes it shoot to a different point of aim if it was zeroed from a position without artificial support. Standing, kneeling, sitting or prone are positions without artificial support. A right handed shooter's zero shooting from a bench such as this will have a zero about 1 MOA to the right of those field positions.

I didn't believe this until I was asked to take my military rifle team to the benches at the range where we practiced and have them shoot their rifles from a bench this way. All of them had their groups a bit to the right using those four positions zeros on the rifles. So did I. And all the groups strung a bit horizontally.

So, it's my contention that unless one's very repeatable in their bench shooting holding the rifle against their shoulder, one should expect some horizontal shot stringing. And it will probably be different that using non-artifical support positions.

 

[hooligan1]

Bart, I shot that five round group off a Led Sled plus as I do all my testing groups. I have never shot with the man I fixed the rifle for, but I'm sure he used a sandbag set up of some type, and he doesn't shoot that often, anyway I appreciate you replying on this thread for me... It's better than an autograph to me.
Thanks,
Andy

 

[reynolds357]

Hooligan, when I am having trouble with a rifle, I try a trick a bench rest shooter who is long passed away taught me. I take fired brass from the rifle and take a neck sizer die and set the decapper long enough to make this work. Take the die and adjust it so that it just barely sizes a portion of the neck. 1/16th of an inch at the most. Long seat the bullets and let the rifling push them back into the case. Pretty much, if the rifle wont group loaded that way, it will not shoot that bullet. You can pretty much get a decent group with about any reasonably suited powder charge loading that way. Once you establish it will shoot the bullet, then start looking for the pet load on a true neck sized case. Then switch to full length if so desired. That trick has kept me from sending several rifles to the pawn shop.
You can do it equally well with a full length die, but I just always use a neck sizer. Bart will probably say I am a Dinosaur, but I hang onto my neck sizing.
And, there are some days that I just cant shoot. I have very high blood pressure and take a lot of medicine for it. When its a little out of whack, my group is a lot out of whack.