Mag Feed Accuracy

[Kritter]

I have finally run a tested you guys have recomended.. checked Coal (ogive) and Concentricity of 4 rounds before and after cycling through rifle and there were no real changes mabe a bump of .001 Concentricity of 1 round. I have now adjusted my Forster button so my neck tension is now .262 after FL Sizing (was .264) i will be going to the range to test groups i will report back after.

[Bill257]

The gunsmith who runs my local range tells me he sees ARs that have a slightly different points of impact based on what side of the magazine the round is fed from.

His method to determine this is shooting at two different targets - one for rounds that are fed from the left side of the mag and the other for rounds fed out of the right side. Compare these groups to groups produced when all rounds are fired at the same target or overlay the left and right targets. (for example the left and right groups could each measure an inch, but when combined, as if shot at the same target, the measurement could be 2 inches)


If the cartridges loaded with the modified expander ball don't prove to be the solution, this two target test may point you to the side with the issue. The and you could examine differences in the feed rams or magazine feed lips.

In .223 my factory crimp die slightly improved groups with some bullets and really opened up them up with another already accurate load / bullet - I'd minimize variables by only shooting one type of ammo at a time and labeling each target.

Good luck and keep us posted on your findings

[LR1955]

The gunsmith who runs my local range tells me he sees ARs that have a slightly different points of impact based on what side of the magazine the round is fed from.

His method to determine this is shooting at two different targets - one for rounds that are fed from the left side of the mag and the other for rounds fed out of the right side. Compare these groups to groups produced when all rounds are fired at the same target or overlay the left and right targets. (for example the left and right groups could each measure an inch, but when combined, as if shot at the same target, the measurement could be 2 inches)


If the cartridges loaded with the modified expander ball don't prove to be the solution, this two target test may point you to the side with the issue. The and you could examine differences in the feed rams or magazine feed lips.

In .223 my factory crimp die slightly improved groups with some bullets and really opened up them up with another already accurate load / bullet - I'd minimize variables by only shooting one type of ammo at a time and labeling each target.

Good luck and keep us posted on your findings

Bill:

It isn't which side of the magazine but rather he is shooting at one target that is left and one that is right. He is probably centered on one of them because that is where his position is focused but when he transitions, he will probably shoot to the direction of the target to the side. My bet is that if he set in one target and shot a group, pulled that target and set another one about five feet to the side of the location of his first target, he would also shoot center. This is because he would get into a new position for the second target.

Put in a bank of five targets, get a position on the center target, then shoot from right to left or left to right in rapid fire. My bet is that the far right target will shot a group to the right of center, the center target will probably be centered, and the far left will probably have a group to the left.

LR55

[LRRPF52]

Yup. I see this in dot drills all the time, as well as on an array of targets when doing accuracy testing. Even the small angle that is required to aim up a little more at the top set of dots is enough to make changes in the position that don't support good grouping.

What I commonly see is a trend where the lower targets on the paper, which are more level with the position, end up being the ones where the groups tighten up. For me, settling the gun into the position, no matter what vertical angle I'm aiming, eliminates this trend.