Zero: M193 55gr FMJ vs Win Ranger 64gr SP w/ 7.5 barrel

[tanksoldier]

So I haven’t run across this issue with my 16” barreled rifles, at least not to this degree.

I train with cheap M193 ball, but our duty ammo is the Win Ranger 64gr softpoint.

I usually use a 50 meter zero, and with M193 ball compared to the Ranger soft points from a 16” barrel at 50m there seems to be little difference.... at 200m the 64gr seems to hit an inch or so higher than the 55gr. I attribute this to the 64gr retaining velocity and maybe a bit more oomph from the better ammo.

However, at 50m with the 7.5 barrel the difference is over an inch and a half, the 55gr shooting much lower than the 64gr. I literally can’t get both to shoot to the same POA at 50m. Haven’t had a chance to shoot at 200m but I assume the difference is huge.

I’m unlikely to shoot the 7.5 pistol in the line of duty. So, my plan is to zero it to the M193 ball and figure out what the actual far zero is with this barrel and that ammo and forget about shooting the duty ammo with it.

...unless somebody can think of something I haven’t thought of?

[Stickman]

You are issued a 7.5" barreled AR? What is wrong with your people?!?!?

[1168]

Define “cheap M193 ball”. It is a very forgivable mistake to refer to all 55gr FMJ as M193, but still not accurate wording.

Also, this.:

You are issued a 7.5" barreled AR? What is wrong with your people?!?!?

[tanksoldier]

You are issued a 7.5" barreled AR? What is wrong with your people?!?!?

No, the department issues a Daniel Defense 11.5 barreled AR.

I bought the Stag 7.5 pistol for myself...

[tanksoldier]

Define “cheap M193 ball”. It is a very forgivable mistake to refer to all 55gr FMJ as M193, but still not accurate wording.

It’s Lake City M193, 1000rd sealed ammo can. Bought it a long time ago....

[opngrnd]

Different guns shoot different ammo differently. I know that sounds weird, but I have had some rifles that have minimal POI changes between different ammo and some rifles that shift noticeably more when I change ammo. I'd say zero with the ammo you would use when it matters, and learn your offset with the cheaper ammo. You may not notice a difference if you are just blasting full size steel targets, etc

[georgeib]

Do yourself a HUGE favor and 86 that 7.5" barrel. Replace is with an 11.5.

[1168]

Interesting. I would swear 193 would be higher.

It’s Lake City M193, 1000rd sealed ammo can. Bought it a long time ago....

[AndyLate]

It's not uncommon for heavier bullets to print higher, especially at short ranges. Lower velocity and higher recoil means the barrel is in a different position when the projectile leaves the muzzle.

Like noted above, different barrels shoot differently.

Andy

[TomMcC]

It's not uncommon for heavier bullets to print higher, especially at short ranges. Lower velocity and higher recoil means the barrel is in a different position when the projectile leaves the muzzle.

Like noted above, different barrels shoot differently.

Andy

Since heavier bullets are generally moving slower, the barrel has more time to move up during recoil and before unlocking. It's why .357's usually strike lower than .38's