Accuracy Suggestions

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Ghostman
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Accuracy Suggestions

Post by Ghostman » Wed Jan 13, 2021 10:35 pm

Got a 300 blk 10.5” no name barrel on this upper from ESAD Arma. I am a good shot. Never had a gun shoot like this before. At 50 yards it was ok, but at 100 yards it was pretty far out there. I was shooting 175 grain advertised 1775 FPS and 220 grain advertised 980 FPS. Both HPBT. At 50 yards I had 1 MOA with both rounds and close to same POI. At 100 yards I had a 3.5 MOA with the 175 and 4 MOA with the 220. The 175 was freedom munitions brand and 220 was Hush brand. Any suggestions to tighten up this group? Does Ammo changes make a big change in this type of gun? Maybe the barrel isn’t up to task? Thanks.

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BJK
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Re: Accuracy Suggestions

Post by BJK » Thu Jan 14, 2021 12:43 pm

What's the twist on the barrel? And with that someone who knows something will be by. :D

Ghostman
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Re: Accuracy Suggestions

Post by Ghostman » Thu Jan 14, 2021 4:05 pm

1:8 twist

Regaj
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Re: Accuracy Suggestions

Post by Regaj » Fri Jan 15, 2021 7:27 am

What kind of sights are you using?

You're (royal "you") not going to get consistent 1-MOA groups at 50 yards without a stable bullet. And absent wind or other environmental issues there's not really anything at those two velocity ranges that is going to meaningfully change by 100 yards. Good groups at one distance ought to translate easily to the other.

Not suggesting you're not a good shot, but If you're running irons or a red dot, my guess is your sights are giving you enough precision for tight groups at 50, but are inadequate for the same precision at 100.

Second guess would be that you've run afoul of sample size. A common mistake is to shoot a group or two of a given load at a given distance and call it good (or not). But until we've put a reasonable number of rounds downrange, we really don't know. Going to 10-shot groups, versus the much more common 5-shot or 3-shot, can be very revealing.

Yes, ammo changes make a big difference. But that's in all calibers, not just 300 Blackout.

Welcome to the forum! (I'm new, too).

BJK
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Re: Accuracy Suggestions

Post by BJK » Fri Jan 15, 2021 9:55 am

FWIW, many years ago when I was playing around with subsonic 5.56 (Sierra 80gr) my 1:7 barrel would stabilize them fine out to about 75 yards. I'd get really nice small groups, but at 100 yards clearly they were destabilizing as seen on the paper, and groups would open to 3".

But I have no experience with .300BLK yet and my barrel is a 1:7. I was hoping someone with experience or more smarts would enter the discussion.

That's all I have.

Regaj, you may be on to something with the sights used since it happens with both loads. I missed that until I went back and reread.

At about 40ish years old eyes can change and not for the better. Optics are our friend when that happens, also getting them checked and Rxs filled are a key.

Now that's really all I have. (smiley face goes here)

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dellet
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Re: Accuracy Suggestions

Post by dellet » Fri Jan 15, 2021 11:33 am

Twist is not an issue, but that does not mean the barrel may not have a problem.

Very common on new barrels to have burr at the gas port and cutting the bullet jackets. look for copper fouling behind the bolt, inside the carrier.

Make sure the holes in the target are round, anything else could be an indication of bullet instability caused by reasons other than twist, but while we are on it, verify the twist rate.

Subs and supers to the same point of impact at 50 yards, not all that uncommon. At 100 yards it will be a separation of 4-8".

A 50 FPS variation at 950 fps with a 220 grain bullet can account for as much as 1.5" of vertical spread at 100 yards

Ammo choices are tough right now, but going with a known performer is essential. Freedom Munitions has a pretty checkered past at least here. You will find posts where the ammo was rejected straight out of the box because the problems were obvious, to claims of sub MOA accuracy. They were bought out of bankruptcy a year or two ago. so who knows.

If I were looking for factory ammo it would be Hornady 190 subs and Remington UMC 120 supers.

Check all the basics like mounts and barrel tightness. How you are shooting, off a bench, bags, bipod might be helpful to know.

A budget build and bottom tier ammo is a good way to get the exact results you have. Not saying it can't be better, but low prices and low expectations generally are a good match.
300 Blackout, not just for sub-sonics.

Ghostman
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Re: Accuracy Suggestions

Post by Ghostman » Fri Jan 15, 2021 6:36 pm

Thanks everyone for feedback and suggestions. Looks like I got a few things to check on.

I am using a Leupold VX3 1.5-5x30 scope and Nikon P series rings. No issues in the mount. This is definitely sufficient for 50 yards, and I think it is ok for 100 yards.

When you mention stable bullet that does get me thinking about the torn hole in the paper. The 220 grain were not as clean of a hole as the 175. I wonder if they are yawwing possibly?

There wasn't really any other environmental conditions, I never got the barrel hot, had a slight cross wind of maybe 5-7 mph. I'll try shooting a few 10 shot groups and see how those do.

I can also verify the twist rate. I'm not sure the barrel brand ESAD uses when they put these uppers together, although I thought todays manufacturing practices would atleast have all barrels capable of close to 1-1.5 MOA?

I didn't think about the burr in the gas port, I'll check for copper fouling.

It's been a real struggle getting ammo. I'm hoping that's what the problem is because that is easily resolved. I'm gathering consumables to start reloading. I really did want the hornady subx 190 gr but can't find those anywhere.

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300Blk
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Re: Accuracy Suggestions

Post by 300Blk » Thu Jun 17, 2021 11:51 am

I have seen some bad burrs on gas ports, but not sure they really matter.

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