5 replies to this topic

[mtn dog]

I zeroed my new Tikka and scope using Hornady 243Wiin 75 gr HP. (That's the ammo I could find on the store shelves at the time for the bullet weight I wanted for coyotes.)Hornady specs are: Hornady 243WIN 75gr HP Muzzle: 3400 fps / 1925 ft.lbs 100 yds: +1.1", 200 yds: 0", 300 yds:-5.8", 400 yds:-17.6"Today some back-ordered HSM ammo arrived from Cabela's. (Also 75 grain.)I won't have a chance to range test it before I leave on a 5-day coyote hunt. The HSM has slightly lower velocity/energy than the Hornady ammo and I could not find a drop rate table.HSM 243WIN 75 gr (V-Max) Muzzle: 3300 fps / 1814 ft.lbs Guys, I know squat about this stuff. Is that a big difference in velocity/energy? Should I expect much difference in drop? Of course I'll begin hunting with what I have zeroed and I'll bring a target stand and try to test fire out in the field if I get the chance - maybe after my last stand before driving to a new location. Just curious what the 100 fps difference will mean if I have to switch to the slower HSM without re-zeroing for it. Thanks.

[Divernhunter]

I would suggest you either use the Hornady ammo or check zero with the neww ammo. The new ammo may not just shoot lower but it can also shoot to the left or right and such. Different bullet/powder with often change where the bullet shoots in any direction.Been there and done that with many firearms and ammo loads. Best to check zero with new combo.My 2 cents

[mtn dog]

I would suggest you either use the Hornady ammo or check zero with the neww ammo. The new ammo may not just shoot lower but it can also shoot to the left or right and such. Different bullet/powder with often change where the bullet shoots in any direction.Been there and done that with many firearms and ammo loads. Best to check zero with new combo.My 2 cents

Thanks.Since I have about 30 rounds left of the 'zeroed' Hornady ammo, I will be the happiest coyote hunter on earth if I shoot all that at predators and have to open the new stuff! That would be some productive hunting and a big pile of fur! And I absolutely understand why I need to re-zero when I switch but I guess my question is more about whether to expect a big difference from the different ammo based on the manufactures velocity/energy numbers. 3300/1814 vs 3400/1925. Is that a little or a lot? Being new to this, I don't know how to interpret the ballistics specs yet.Thanks.

[Divernhunter]

That is not a huge difference in speed. BUT the trouble is not the speed. The big trouble comes from a different bullet etc. Some rifles will show this with 2 different bullets of the same weight(but different shape) with all other factors the same. Some will shoot the same weight bullet but different brand of ammo into completely different spots.Use the ammo you have that you sighted it in with and good luck. If you fire all those rounds then do a quick test target with the new before you try them on game. Of course if you run out of ammo and need more animals taken out you could always call me.

[Colin]

True, it's about the bullet/rifle not the velocity. In my .25-06 (for whatever reason) the 115gr Nosler Partition hits about 5-6 inches higher than anything else going much faster. 5 out of the 6 different brands/weights of bullets I'd used would group into an inch at 100 yards. For whatever reason, the Partitions hit much higher than the rest.

[dabob]

The speed difference is not enough to worry about. But the two different bullets may not group in the same spot.