First and last round flyers in AR are driving me nuts

[Float Pilot]

My 6.8mm SPC Stag has a bad case of the first and last round flyers.
The first chambered round always goes out of the goup and the last round always flies off out of the group as well. Some super handloads can make the flyer be within an inch, but some otherwise good loads really show this annoying trait.

Here is a classic example. I had to chamber the firt round in this shooting string, then had to rechamber another round after a failure to feed. Then you can see where the last round went due to the drag of the magazine follower on the bottom of the bolt carrier.

[sweepint]

We run into a little of this with SR25 at 200yds. Your first 2 are just cold bore shots and is some what normal. Your last rd is a bit of a ? If i were to guess it might be that you are pushing into the shot which will cause the poa to poi to drop a bit.

Not knowing what dist, and plat form you are using makes it a bit more questionable.
Hope this helps some.

PS its still pretty tight.

[Float Pilot]

The platform is a 6.8mm SPC Stag, A5 16 inch barrel, SPCII chamber, 1 in 10 twist.
Range 100 yards, temp 5 degrees above zero.

Those are not cold bore shots. I had just finsihed firing 20 rounds with two other experimental loads.

This rifle does NOT have M4 feed ramps which I believe is part of the problem. The first round manually chambered from the magazine always prints off someplace else.

In this photo there were two manually chambered rounds, the second was half way through the firing string when I had a failure to feed. You can see how the group is split when my eyes started using a diferent aiming point, (or maybe I was shouldered a little differently, it was kinda cold and I am kinda old)

The last round flyer is probably from the mag follower rubbing against the bolt carrier. I saw this fairly often with issue M-16s while supervising quals. Just never to this extreme.