Rifle Grouping

I posted an ammo question a few weeks back about my sons youth Marlin .243. I tried another round today. This round was also a Hornady but this time it was a 95 grain ballistic tip. I shot 20 over about a half an hour time. I forgot my cleaning stuff so it wasn’t cleaned after so many rounds like I normally do. This round shot worse than the first bullet type with only a few consecutive shots that were like an inch apart. Everything else was all over the place. Some consecutive shots were 10 inches apart. Do I need to move on from Hornady ammo or do I have a bigger problem possibly with the gun or scope? Right now I have a cheap BSA scope.

DT

Kinda sounds like scope to me. That is exactly what bad scopes do and I’ve personally witnessed that happen more than once, but I’m the last guy to ask. Good luck man.

Sometimes you get what you pay for, don’t go cheap with optics!. But, given there is such a difference in shot locations on the target, you might want to check and be sure the scope mounts are all screwed down tight with loc-tite. Loose mounting can cause just what you’re describing.

At what distance are you shooting?

With variance this great I would start at no more than 25 yards and see if you can get any kind of consistency out of the gun.

I was shooting at 50 and 100. It was windy but shouldnt have been enough to cause this.
DT

check the barrel. I bet you have copper fouling that is throwing wild shots.

As mentioned it could a bad scope, fouling, or ammo. Hornady tends to be a hotter or faster load. They do a lot of custom mixes with their powders, so its hard to know the specifics to any one charge. But the fps on their rounds are usually faster than most loads. try a slower round in the same bullet weight and type. Faster is not always better. I didn’t look at your profile, where are you located?

I would not expect the kind of variation you’re indicating would be an ammo problem, especially with factory loads.

However, I will say that you unwittingly made an unfortunate choice for test ammo. As Randy indicates, Hornady Superformance is some of the highest velocity ammo on the market and therefore it could be a contributing factor.

But I don’t think it’s the whole story. While the Hornady Superformance loads tend to be faster than other commercial ammo, in my experience with handloading and going past the rifle’s sweet spot is that groups tend to spread, but not by nearly as much as you seem to be indicating.

Qustion: Can you estimate two things for us.

1. How many total rounds have been through this rifle?
2. How many rounds since you’ve cleaned it?

Because the rifle in question is a hunting rifle for your son and since you don’t appear to handload, I’m not at this point suspecting copper fouling. I could be wrong, but unless you’ve run several hundred or a thousand rounds through this gun, this wouldn’t be my leading suspect.

My #1 suspect is the scope and that’s what I would want to eliminate as the first variable.

Here’s what I’d do:

Get about 4 boxes of Plain Jane factory ammo. All the same kind. We want to eliminate variables here not introduce more. Personally, I would favor getting something at around 70 grains, but I think the key here is stay middle of the road. Don’t get the heaviest, don’t get the lightest.

At the range, fire a couple of groups to confirm you’re still having an issue with the new batch of ammo.

Hopefully, you have another scope you can mount on the gun for testing purposes. Unfortunately, the only way you’re going to find out if it’s the scope is to switch scopes. After confirming that the new ammo choice still produces poor accuracy, I would switch scopes.

All of this takes time and effort, I know. The problem is that there are multiple variables. IMO, since it’s a cheap scope, I’m taking a guess that I think is based on the probability of the other factors being the issue. Both the ammo and copper fouling could contribute, but I doubt that either of these factors alone would cause this kind of inconsistency.

Grouse

Thanks to all for taking the time to try and help figure this out. There is approx. 100 rounds through the gun and it was cleaned after my last shooting session.
DT

FYI for those interested. I have seen massive copper fouling show up in a barrel in under 20 rounds (we are talking clean barrel to massive fouling). Hot loads (among other things) were a factor.

In my experience I don’t think a person needs high numbers of rounds shot to achieve fouling.

Quote:

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FYI for those interested. I have seen massive copper fouling show up in a barrel in under 20 rounds (we are talking clean barrel to massive fouling). Hot loads (among other things) were a factor.

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What were the other factors?

Nothing’s impossible, but with <100 rounds through the rifle it’s not what I’m seeing as the most probable. I’ve got a .243 that’s approaching 1000 rounds, mostly hot PD loads with no fouling.

With a cheap scope, that’s my leading suspect simply because I’ve seen any number of Tasco and other low end scopes fail. If he had a Zeiss or Leoupould scope on the rifle, it’d be a different story.

Grouse

Ruger M77 25-06 shooting factory Remington Cor-Lokt loads. That barrel hated those bullets and would suck the copper off of them.

Of course you are right as well. I have seen loose receiver screws make wild groups. I have seen loose scope screws and mounts make wild groups. Lots to consider. I personally would consider ALL options.

I would thoroughly clean the barrel with a good solvent for copper, like C-10…recheck the receiver and scope screws for tightness…Get a good zero at 25 yds with factory ammo like Remington Green 80 gr bullets…and let us know what happens.

UPDATE: I ended up buying a Burris E3 as recommended here by a few. I sighted in the gun today. When I left the range today I was in a consistant 3 inch circle at 100 yards with a few dead in the center of the bullseye. My shoulder was sore at the end as I also had to check my .270wsm which kicks like a so I assume when fresh I will be able to dial them into an inch or less at 100. The only issue I have now is I sighted in with 100 grain core lokt’s. They are now sold out everywhere in my area and I wanted to shoot it tomorrow at 200. I may have to switch ammo again and hope the gun likes it also.
DT

So the cause was a scope gone bad?

Grouse

I think I can safely say yes. The mounts seemed fine when I took the old scope off.
DT