[Stamp Mill]

I have a M1A Loaded with iron sights. It is new this year. Because of range limitations, I have been only shooting 100 yards. After about a dozen range outings and roughly 600 rounds of Federal XM80 through it, mostly in five shot groups, I can get a couple of groups under three inches on any given outing. I have it zeroed for the 100 yards.

If I switch to m118, is there a basic sight elevation change to make? I know there a lot of variables, most of which make a difference at the longer distances. But for the 100 yard distance is there a starting place that generally works?

 

[2336USMC]

I suggest you'll just have to try it and see. There should be very little difference in trajectory at 100 yards, the centerfire medium rifle cartridges are so close over 0-100 yards it will only be a fraction of an inch difference.

What will make a bigger difference, and can't be predicted, is that your rifle is likely to throw the heavier bullets to a different point of impact- not because of gravity or trajectory, but because the barrel whips differently with the heavier bullets. The only way to find out is to try.

 

[KurtC]

At 100 yds, the M118 usually prints just an inch or two higher than M80. At longer ranges, it will print lower.

 

[3Gunnah]

I would bottom out my sight and go up 10 with a 6 o'clock hold at 200 with the m118.GI2

 

[JayKosta]

As KurtC said, the same sight settings for XM80 should be very close when using M118 - at least out to about 300 yards.
M118 will have more recoil due to the heavier bullet, and will likely have more 'muzzle rise' which causes it to POI a little higher at 100 yards.

The shooting position also make a difference with the amount of recoil rise. If a tight sling is used the rise difference will be less. If shooting from bags or standing-no-sling, the difference will be a more.

Jay Kosta
Endwell NY USA