but I believe its more my technique and concentration fading.
Would planking help?
Install a good quality, rigid, comfortable cheek rest and adjust it so that your eye is aligned with the sights at the "cheek rested" position.
Neck fatigue is caused by the muscles at the back of the neck having to support the weight of the head for long periods of time.
Check the Mystic Precision site for cheek rests.
So you mean a lot of the weight of your head should rest on the cheek rest? What is the "cheek rested" position and how do you find it?
How much do you pull the stock into your shoulder with the pistol grip hand? How much weight do you put on your cheek?
Someone posted some awesome links in regards to this but I can't remember where to find them. I saved the article as a PDF it was so helpful. It talks about firm hold / semi hold etc. it was a good read.
It's called "Bugholes from a Bipod" and talks about some guy named "Froggy"
So you mean a lot of the weight of your head should rest on the cheek rest? What is the "cheek rested" position and how do you find it?
I notice that my accuracy quickly deteriorates as I shoot prone. Neck gets tired, scope starts winking out and accuracy goes all to hell. I was shooting my AR off a bipod and rear bag this week, and the first two strings of 5 shots went incredibly well, then things started getting worse, and I couldn't even keep it MOA. I took a break, went back, and it started punching a nice group again. I find I get tired, start putting weird pressure on the stock, have trouble aligning my eye with the scope, and even find the trigger pressure starts to feel excessive.
I'm shooting prone on a mat, bipod on rifle, bunny ear style rear bag.
Any suggestions?