Shooting Question

CObullfinder

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So I have a bit of a puzzle here. I sighted in my .270 today at 100 yards. The first shot, cold bore, was dead on but 3.5in high. Subsequently, the next 4 shots were dead on and 1.5in high in a quarter sized grouping without any adjustment made to the scope. I know you're probably thinking I pulled the first shot up, but I have a pretty good bench rest setup and it felt exactly like the other four. My feeling is that my gun shoots high with a cold bore because on a bull and a buck I shot last year, I missed on my first shot on both animals, but my second shots were both perfect. Has any one heard of this or know what might cause it? I am planning to do more shooting to see if this is consistent. If it is, I'll just plan on aiming lower on my first shot. Thoughts?
 

sbhooper

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Not unusual, but it sounds more like a "clean bore" issue vs a "cold bore" issue. Is that the first shot from a clean bore? My experience is generally that a cold bore shot is lower and the subsequent shots tend to creep up as the barrel warms. Most guns change poi from clean bore to subsequent shots. Foul the barrel with a few shots, sight it in, and don't touch it until after the season.

Let us know some more details.
 

JLS

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Not unusual, but it sounds more like a "clean bore" issue vs a "cold bore" issue. Is that the first shot from a clean bore? My experience is generally that a cold bore shot is lower and the subsequent shots tend to creep up as the barrel warms. Most guns change poi from clean bore to subsequent shots. Foul the barrel with a few shots, sight it in, and don't touch it until after the season.

Let us know some more details.

This was my first thought also. Are you cleaning the bore every time?

I really doubt a cold bore that is fouled would be off every time. A cold bore that is clean will.
 

Paul in Idaho

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Sounds too familiar. I have had similar results but with a bit of sideways shift as well. I agree with the others - is the first shot immediately after cleaning? I found a big difference between clean and fouled in my gun.

If it is, I'll just plan on aiming lower on my first shot.

From painful personal experience, I'd advise against this. I once had the same situation as you describe, held low on my first shot at an elk ... and hit low. A slam-dunk clean kill opportunity turned into a distressing recovery. Figuring out and solving the POI shift would be very preferable.
 

CObullfinder

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This is interesting. So yes, the first shot was the first since I had cleaned it. I'll shoot again tomorrow and see what happens. What is poi? Thanks for the help!
 

JLS

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This is interesting. So yes, the first shot was the first since I had cleaned it. I'll shoot again tomorrow and see what happens. What is poi? Thanks for the help!

My bet is the first shot (assuming you have not cleaned it since that session) will be right on the money.

POA = point of aim, where you're holding the crosshairs/sights
POI = point of impact, where the bullet actually hits

I used to obsess with cleaning bores. Now, I clean it, shoot a few fouling shots through it, and leave it for the season. Doesn't mean you can't wipe out the bore with a dry patch, just don't clean the copper out.

A friend of mine told me he'll go hundreds of rounds through his sniper rifle between cleanings.
 

tarheel

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Pretty much every gun with a clean bore will do this. My Win 70 in .243 shoots up and left and usually requires three fouling shots to come back to where it will shoot consistently.
 

huntin24/7

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I shot my .257 wby the other day at 300 yds under calm conditions. I fired 2 rounds, and I went to check. they were 6 inches apart and I couldn't figure it out. 1 round was where I thought it should be. Then I remembered that I had cleaned it the other day so I went back and fired 1 more round. That round hit about 2 inches from the other round that hit where I thought they would. The rest of my groupings were good after that.
 

sbhooper

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Barrel makers love people that obsess with cleaning the bore all the time. They get more customers that way. A bullet rides on a layer of copper that needs to be there. If everything is removed regularly, then the wear on the barrel is more pronounced.

SHOOT IT! DON'T SPEND ALL YOUR TIME CLEANING IT! If the bore needs cleaning, your groups will tell you. Just run a couple lubed patches down it once in a while if you shoot a lot. That will suffice to remove excess carbon. If your groups open up, then strip it and start over.

After a thorough cleaning, I figure on at least two fouling shots to get things back where they should be. If you shoot all-copper bullets, then they may need cleaning a bit more often.

A friend of mine is a police sniper. He was incessantly cleaning his rifle and I told him not to. He thought that I was full of it until he talked to a friend of his that works for a barrel company and he told him the same thing that I told him. Amazingly, his groups shrank thereafter.
 
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CObullfinder

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So just for clarification, I clean my gun once a year, before I sight it in, and then not for another year after. I'm not a gun expert, I just want to be confident that when I put the cross hairs behind the front shoulder and squeeze the trigger, that's where the bullet will go. This is all really interesting to me. So does the lack of copper fouling affect the spin of the bullet, and therefore alters the poi?
 

JLS

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So does the lack of copper fouling affect the spin of the bullet, and therefore alters the poi?

The bearing surface of the barrel is altered as copper fouling builds up. A clean bore has a different bearing surface than a bore with several fouling shots. And yes, these affect the POI.

Don't clean the copper out of the bore during hunting season without taking the time to put several fouling shots down the tube after you do.

Clean the copper out when your groups start to go to hell. Other than that a few occasional patches with some Hoppes on it is all you need.
 

CObullfinder

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You guys were right. Went out today, gun was right on the money. 1.5in high at 100 yds. I even had a little fun and blasted a basketball at 250 yds, dead on at 250. Thanks for the help, I definitely feel confident in my rifle now, no holding low on the first shot. Now here's hoping I can find a bull in two weeks when my season starts! Shooting is the easy part, finding elk is the challenging part!
 
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