Zero Problem

Discussion about rifles in 300 AAC BLACKOUT (7.62x35mm), hosted by the creator of the cartridge.

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Cowman1944
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Joined: Mon Apr 27, 2020 11:04 am

Zero Problem

Post by Cowman1944 » Mon Apr 27, 2020 12:15 pm

Good Morning, Friends.
A friend just bought a new 300 Blackout Pistol with a 10.5 inch barrel.
The initial zero is 50 yards and has a beautiful POI pattern ... less that 1/4 inch ... some holes touching. Shooting Remington 120 Gr OTBT rounds.
Shooting Barnes 120 Gr TAC-TX-BT, the pattern is just as beautiful as with the OTBT ammo.

Checking POI at 100 yards with 120 Gr Remington OTBT rounds, the POI pattern is 1/2" - 3/4" Below the Bull.
Checking POI at 100 yards with 120 Gr Barnes TAC-TX_BT, the POI is 4 inches above the Bull. Second shooter confirmed the same POI.

Conclusion - I don't believe it's the shooter. Two different shooters, same result.

Specs on Remington - Muzzle velocity - 2202fps; .297
Specs on Barnes - Muzzle Velocity - 2150; BC .358 - No wind

Questions:
1. Is it the ammo?
2. Is it the barrel/pistol not liking the ammo?
3. Does gas system need tuning?

Your kind help would be appreciated. Thank you.

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20X11
Silent But Deadly
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Location: Aurora, CO

Re: Zero Problem

Post by 20X11 » Mon Apr 27, 2020 1:41 pm

1. Yes... Different bullet profiles/ ballistic coefficients
2. No...seems the barrel likes them both
3.Hell no...no relation

Cowman1944
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Re: Zero Problem

Post by Cowman1944 » Mon Apr 27, 2020 2:18 pm

Thanks 20X11. I appreciate your comments.

fancygunz
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Re: Zero Problem

Post by fancygunz » Tue Apr 28, 2020 4:03 pm

Cowman1944 wrote:
Mon Apr 27, 2020 12:15 pm
Questions:
1. Is it the ammo?
2. Is it the barrel/pistol not liking the ammo?
3. Does gas system need tuning?
Your kind help would be appreciated. Thank you.
1. Yes, most likely
2. Depends, how big were your groups with each load? If one grouped better than the other I would say there was a relationship between the barrel and the ammo.
3. No, only if you had issues cycling.

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