First shot always 1 MOA high

[effendude]

Interesting situation that I have not ran into before and thought I would see if anyone else has had similar issues. I have a hunting rifle in .284 Shehane, Surgeon LA, McMillan A3 stock, Bartlein 5R barrel. I built it to use up tired match brass and I am glad I did. The rifle is an absolute hammer on game and targets, 1/4 to 1/3 MOA at distance which is as good as I can hold with a 22X scope. My issue is the rifle always sends the first shot 3/4-1 MOA high, and the rest of the shots into one ragged hole. I am talking about starting with a fouled bore, I don't clean it in between the 10 shots I shoot occasionally but it does get cleaned after each season, maybe 50-100 rounds between cleaning. Normal checks such as action screws, scope rings, etc all ok.

It currently has a Thunderbeast Ultra 7 suppressor, could the suppressor do this? I will retest without the suppressor this weekend to see if the suppressor is the cause.

Any ideas?

Thanks,
Scott

 

[dragman]

coupe ideas:
Maybe something in the barrel needs that shot after it sits (hard carbon ring or something???)
More likely it's a shooter error like maybe you need that shot to get into position??

 

[Eddie Harren]

I have had several barrels over the years that printed the first shot away from the following rounds. I always fire a couple of foulers before going to the record bull.

 

[M-61]

I agree with dragman's 2nd sentence. When I find myself in this type of position with no real reason, I have a friend who basically shoots with the same degree of accuracy I do. If you have that, let him takes the first shot. See what he gets. Finding someone that shoots close to what you do is often not easy but it has shown me more than once that it is not my rifle, reloads, etc. It's simple....it is ME. You are convinced the first shot is going high and it does. See what happens with another shooter. If I am going to screw a group up it will be when I have a fabulous four shot group on the paper. and even though I am shooting against myself the pressure is on for that 5th shot.

 

[ultraedge]

I think the trouble is stress in the barrel. I had a Bartlein 5R that shot the cold bore shot 1 moa high. All the rest of the shots were in the group. This went on for the life of the barrel. When I had a new Mullerworks barrel installed, the problem went away.I also noticed that when the rifle sat in my truck during extremely hot weather and the barrel was hot to the touch before the first shot, then it did not shoot high. Gary

 

[effendude]

Thanks for the replies, and I will let you know what further testing reveals. I chuckled at the shooter error comments because that is usually my first response when someone complains a rifle doesn't shoot well.

Scott

 

[SmokinJoe]

How does it shoot from clean. Sometimes you can come up with a cleaning regimen that will give a 1st shot that at least stays close to the following shots. From the post above; if barrel stress could be the problem, you could take it off and send it to be cryo'd to eliminate residual stress maybe. Barrels can be weird.

 

[LitLBoy]

It's the suppressor

 

[gunnermhr]

More likely it's a shooter error like maybe you need that shot to get into position??

If you believe it's the barrel send it to me, I had the same issue and found it's exactly what dragman is stating. Work the gun in the bag / rest before firing the first shot, a shooter much better than me told me this and my problems went away. My issue happened after my sighters, moving to the record target. Your in a different scenario but the application has to be the same

 

[gme]

Scott,
I have a 7MM RSAUM that does the same thing, I believe it's due to the carbon residue in the bore common the powder I use (H1000) I've found that if I pull a dry bore snake once or twice through the bore prior to my cold shot the gun is much closer to POA when warm

 

[billlarson]

This situation is not at all uncommon ........ during my 60 yrs. of shooting both competitively and hunting.....I have owned few guns/barrels that would not throw the first shot out.....
I can name quite a few variables to blame.... assuming bedding/scope/hardware all good...
barrel temp/ambient temp
cleanliness of barrel/rounds from last cleaning....
powder type/cleanliness
Gary`s statement above on bores snakes is correct..... I`ve seen it work......
Knowing your equip.is the key...... now a tuner may help this problem.... but on a hunting gun weight is of paramount importance.....
So..... in my reply..... and not really answering your problem..... I apologize......
Just stating a lot of us have face/faced this same problem (?).....
bill

 

[Comrade Terry]

Work the gun in the bag / rest before firing the first shot....

+1

 

[lpreddick]

I have noted this also. I may be way off, but I suspect powder residue left in the bore will absorbe/attract moisture and get "fluffy". This "fluffiness" affected the first bullet. This bullet seems to flatten or remove this stuff and rest go one hole where you expected. Run a patch thru bore and this "fluff" gives resistance...shoot several, then a patch slides thru bore with minimal resistance. Patch a cold bore prior to the first round and see if any difference.

 

[M14AMU]

Hold 1 MOA low!

 

[ebb]

I have a Ruger 308 VT my friends and I bought three at the same time. Well Dons was a 223 but they looked exactly the same. Mine would shoot the first shot dead in the exact center of the bullseye every time I took it to the range. But only the first shot. I was about a 1MOA rifle. But the first shot was always in the center. I think what you guys are talking about is the first shot has no heat in the barrel and all the subsequent shots do have some heat in the barrel. I think that's why they call it a cold bore shot.

 

[Boxcar77]

Test with and without the suppressor. If the cold bore shot is consistent you can adjust and correct for your cold bore shots. All my data books have cold bore pages.

 

[Martin52]

OP- mine is the opposite - first shot is usually low 1moa and 1moa left. This applies both where the barrel is cold and clean and also when it's cold and dirty. The second shot is about 1/4 moa high, but windage is good. 3rd shot, elevation settles down, windage good. Just seems to be the pattern.

 

[dcali]

Some barrels just do that. The ones I have had that do, they tend to do it consistently and settle down by the third shot. Others are fine from the first shot. Go figure.

 

[effendude]

Thanks for all the replies. For clarification, this is NOT a BR rifle, it is a hunting rifle and I shoot it that way: Bipod up front, small rear bag behind. The rifle shoots 1 ragged hole groups at 100, 1" groups at 300 which is good as I can hold with a 22X scope. Shots are fired about 5 minutes apart to avoid heat issues. The fouling has been "aging" in the rifle for almost a week. I plan to simply pull a boresnake through before testing again to see if the fouling is the culprit. If the results are the same, I will remove the can and retest without it.

Scott