accuracy ? what happened ?

R

rebs

New member
For my Colt match target competition AR with Leupold vx3 scope, I loaded 20 rounds by weighing each individual charge, sorted Sierra 69 gr match king bullets by weight. The first 10 round group was 2 1/4 inch at 300 yds, the second 10 round group was about 6 inch all over the place. What could have gone wrong ? was it all me messing up on the second group ?
 
I do not know, but I have loaded 12 different loads using 12 different case head stamps with different bullets and different powders when testing a rifle. My experience is I do not have flyers and the groups do not open up but they do move around. 120 rounds is a long secession and I find nothing entertaining about heating the rifle up.

I bid on and won a rifle that was considered ugly, reloading forms pilled on the builder/seller as in; "What was he thinking?". I was thinking anyone that could build a rifle that ugly had to know what he was doing. I loaded 12 different loads of 10 rounds each with different cases, bullets, powder etc. and headed for the range. It took most of the day but I found there was nothing I could do to improve on the accuracy; the rifle liked everything.

F. Guffey
 
wind ? mirage? barrel heating up ? a scope mount loosening, change in hand grip or cheek weld

hard to say without the rifle in hand and a video of you shooting the groups
 
What could have gone wrong ? was it all me messing up on the second group ?
Click to expand...

It's you!:p
or, its not.

The way to find out is shoot the rifle again. Shoot it with some ammo of known performance (need not be match ammo) AND have someone else shoot it, as well.

If someone else shoots it well, then, its you.
If ammo of a known standard (like a factory load) doesn't group well, then its the rifle. OR its the rifle sights....

Put a different scope on it, or shoot it with iron sights and see if there is any change. A scoped rifle, shooting 2" group for 10 shots, then shooting a 6" for the next 10, is most often a sight issue. Loose (mounts) or broken inside (reticle shifting).

Right now, leaving you out of the equation, I would look first at loose scope mounts, or failure of the scope itself. IF the mounts are properly tight, and a different scope cures the problem, you need to call Leupold.
 
When shooting at 300 yards a lot of things can "go wrong" ,most probably it was the wind , three football fields away, picked up and you didn't notice it from where you were shooting from .
Watch the surroundings , grass / leaf movements for the wind . Doping wind speed and direction and making the correct sight adjustment is an art , black magic , science and a gift that must be developed over time. It's called experience .
Keep at it.
Gary
 
Thank you for the replies. I did check the scope mounts and all are tight. I went to the range this morning with my normal loads using my Hornady LNL press and shot four five shot groups all under 2 1/2 inch so I am thinking the bad group is all me. Some times my cheek weld is questionable. Hard to get it exact every time. Maybe a riser on the stock would be a good idea. Or maybe if anyone make4s a whole different stock for an AR
 
Thank you, I watched the videos and they were very helpful. I am going to work on my cheek weld.
 
A doubling of size for the second string of ten out of twenty is pretty unusual. If it were the third or fourth or fifth string, I would be checking for the barrel tending to accumulate copper fouling unusually quickly. I had a Garand barrel that could shoot a possible up to about round number 35. Between 35 and 40 I would drop 9's, then between 41 and 50 it was always 8's and 9's, and it took a long time to clean all the copper out afterward, too. I could feel the constriction with a patch on a cleaning rod.

I recall getting some bad shots in prone with my tac rifle when I got my elbow too far under the gun and with too little force opposing the sling, and that wobbled during recoil and threw 9's.

But I am guessing you are shooting at a bench off bags. Bag position and point of contact on the gun, how firmly the stock contacts your shoulder and your trigger hand's grip can affect POI in much the same way cheek weld consistency does. The cheek weld can have one other effect though, if your scope doesn't have parallax correction. Then the inconsistent weld means not looking through the scope at the same angle each shot which will move the crosshairs off the actual POI.
 
Unclenick, I am shooting off a bench with a caldwell the rock front rest and a leather rear bag. The Leupold vx 3 scope has parallax adjustment which i use for 300 yds. The last time out I did notice needing to move my head around to get the right picture through the scope so I am thinking a poor cheek weld, right ?
 
If you were moving your head around it very well could be the cheek weld. It could also be that moving around changed the tone of the muscles the gun recoils into, which can shift impact laterally. Also, have you tried military sling prone position? With the Garand, I've actually equaled or outshot my bench groups that way at times. It just seems to stabilize both the gun and me.
 
Way off topic here

I'll take a good F class bipod over a rest or a sling anyday of the week. I bought a nice Sinclair rest but still shoot F open off a Sinclair F class bipod with the cant disabled and a bunny bag. The rest does make a nice doorstop however. A friend offered me a deal on a Farley rest last year but after trying it out for a range session I hated that damn joystick and went back to my bipod and squeezing the bag

But the longer range the range the more the shooting technique plays into it for sure. Environmental factors have more of an effect also
 
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