Sighting in 460 XVR issues, need advice

Typetwelve · Sep 9, 2020

Ok...so here's the quick rundown. S&W 460, 7.5" barrel. Mounted a Burris handgun scope to it and took out 4 types pf ammo (all 460):

Hornady factory 200g
Hand load Berrys 250g over 13g Trail Boss
Hand load Hornady XTP MAG 240g, chrono'd at 1900 fps ave
Hand load Hornady XTP MAG 3000g, chrono'd at 1700 fps ave

So...to get on paper at 50 yds, I started with the super light 250g Trail Boss loads. I got on paper, swapped to the factory 200g XTPs. To my surprise, they shot near identical POA as the mouse fart Trail Boss 250g.

Ok...move to the 240g...and I'm about 11" high. Wow, ok, move to the 300g and once again, 11" high and near identical POA as the 240g.

I go back and forth between the ammo and the results are the same. 200g and 250g, same POA. 240g and 300g, 11" high but same POA.

I get the POA of the 250g slow loads being way off from the faster loads...but the Hot 200g being the same as the light 250g and the hoter 240g being the same as the 300g...and those two groups showing a 11" difference is new to me.

I plan on shooting the 240/300g the most, so in the end I used that as my zero. Going back, my light plinkers and those Factory Hornady 200g are now 11" low from POA.

I'm stumped.

dickydalton · Sep 9, 2020

With mine zeroed at 100 yards with 200 grain factory all of my reloads hit about 4 inches high. That's 300 jacketed and 360 LBT hardcast. Because the only animal I have ever hunted with it until now was whitetail deer in MN I had factory 200 grain Hornadys in it. They were consistantly about 1 1/2" at 100 yards. I'm gonna trade it for a 1927 Tommygun next week because I can't hunt anymore.

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dickydalton
May 13, 2020

460

labnoti · Sep 9, 2020

In some cases, the recoil is going to cause more muzzle rise before the bullet exits. If this happens, the POI will be higher.
In other cases, the bullet will exit faster and get out of the muzzle before it lifts much. The POI will be lower.

So it is reasonable for a heavy bullet (250g) going a low velocity (light load) to drop to a low POI. Then a lightweight bullet (200g) going high velocity (hot load) will also strike a low POI because it's getting out of the muzzle before it rises.

The 240g is hitting with a higher POI because the muzzle is rising. Recoil is higher and the velocity is not enough for it to get out before some muzzle rise. The 300 is exiting at even higher muzzle rise, but it it has time to fall to the same POI as the 240g.

edwardware · Sep 9, 2020

@labnoti hit it. Long barrel dwell time with heavy recoil results in higher POI at short range because the barrel attitude rises appreciable before the bullet escapes. At long range, the lower V takes over and POI drops relative to a lighter bullet.

edwardware · Sep 9, 2020

dickydalton said:
I'm gonna trade it for a 1927 Tommygun next week because I can't hunt anymore.

You didn't ask, but. . . you should heft that Tommygun and ask yourself how often you're really going to lug a 13# barbell with goofy ergonomics out to shoot. It's a lousy semi-auto 45ACP rifle.

Now if you're trading into a real Thompson, I'll just shut up and quietly envy you.

Big Bore TX · Sep 10, 2020

labnoti said:
In some cases, the recoil is going to cause more muzzle rise before the bullet exits. If this happens, the POI will be higher.
In other cases, the bullet will exit faster and get out of the muzzle before it lifts much. The POI will be lower.

So it is reasonable for a heavy bullet (250g) going a low velocity (light load) to drop to a low POI. Then a lightweight bullet (200g) going high velocity (hot load) will also strike a low POI because it's getting out of the muzzle before it rises.

The 240g is hitting with a higher POI because the muzzle is rising. Recoil is higher and the velocity is not enough for it to get out before some muzzle rise. The 300 is exiting at even higher muzzle rise, but it it has time to fall to the same POI as the 240g.

This...

buck460XVR · Sep 10, 2020

Your experience is not unique with your .460. This is why, once I found a good accurate load with my .460 and 300 gr bullets, I haven't used much of anything else, even when just shooting paper. Just too much difference between POA and POI

Sighting in 460 XVR issues, need advice

Typetwelve

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dickydalton

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labnoti

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edwardware

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edwardware

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Big Bore TX

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buck460XVR

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