possible cause?

[BULLET 05]

New to reloading and I have noticed something with some of the results in my reloads for my .223. I will usually shoot a 4 shot group with some test loads. I have noticed that on more than one occasion I will have 3 rounds make one hole and the 4th round will be 1/4" to a 1/2" off. Is this mainly due to me, or my factory gun or something in my reloads or all of the above. I understand that this is a tough question to answer but just thought I would try some ideas. The thing that bugs me is why the 1/2' jump with the one round.

 

[LHSmith]

Possibles: 1/Bedding issue due to barrel heat 2/ a common malady to SR BR group shooters....one tends to get excited after producing a group in the zero's or low ones and tends to jerk the trigger (or some other shooting form mistake) in order to beat the conditions on the last shot in an attempt to preserve a possible record or win small group award. 3/ barrel mirage -use a mirage shield 4/ Allowing a round to sit in the chamber too long allowing the chamber to transfer heat to the powder through conduction -aka "cooking a round in the chamber".

 

[dkhunt14]

A change in conditions, different bullet or a hundred other things. Mat

 

[BULLET 05]

Possibles: 1/Bedding issue due to barrel heat 2/ a common malady to SR BR group shooters....one tends to get excited after producing a group in the zero's or low ones and tends to jerk the trigger (or some other shooting form mistake) in order to beat the conditions on the last shot in an attempt to preserve a possible record or win small group award. 3/ barrel mirage -use a mirage shield 4/ Allowing a round to sit in the chamber too long allowing the chamber to transfer heat to the powder through conduction -aka "cooking a round in the chamber".

Thanks a bunch. I had never thought of the cooking the round thing. I usually try to wait until I am ready to fire but I don't do it every time. I should have thought of that. I figured it was a huge chance on the human error I just thought I could get a few ideas on some other possible causes.

 

[Shynloco]

For what it's worth, what LH and Matt wrote is spot on. But there are several other issues that I've found give me the same headache. And what I've found is that sometimes, components we use such as casings, make a difference. For instance, I mostly use Lapua brass because of it's consistency. But there are many other brands that people use and oft times, unless annealed, brass will promote different neck tension. In other words (and addressing your cited situation) you could have three consecutive casings have one neck tension, and that pesky fourth casing, might have a completely different one, hence the infamous flier 1/2" out. I get that from range pick up that I use to reload for plinking and not precision shooting. Then of course there always the HEAD GAME where you actually know you have three in a tight group and you gotta put that fourth there for pride. And sometimes, you flat sych yourself out and you make some minor adjustment in approaching the shot and WHAM, "i done screwed." Trust me, been there, done that! And I see posts all the time of people complaining about the same thing. So don't feel like the Lone Ranger. Many have been there and many are yet to experience that frustrating event. But stay with it and keep at it. You might say its also part of the challenge of shooting accurately.

Alex

 

[Larryh128]

For what it's worth, what LH and Matt wrote is spot on. But there are several other issues that I've found give me the same headache. And what I've found is that sometimes, components we use such as casings, make a difference. For instance, I mostly use Lapua brass because of it's consistency. But there are many other brands that people use and oft times, unless annealed, brass will promote different neck tension. In other words (and addressing your cited situation) you could have three consecutive casings have one neck tension, and that pesky fourth casing, might have a completely different one, hence the infamous flier 1/2" out. I get that from range pick up that I use to reload for plinking and not precision shooting. Then of course there always the HEAD GAME where you actually know you have three in a tight group and you gotta put that fourth there for pride. And sometimes, you flat sych yourself out and you make some minor adjustment in approaching the shot and WHAM, "i done screwed." Trust me, been there, done that! And I see posts all the time of people complaining about the same thing. So don't feel like the Lone Ranger. Many have been there and many are yet to experience that frustrating event. But stay with it and keep at it. You might say its also part of the challenge of shooting accurately.

Alex

+1 If you aren't annealing & neck turning, it's probably neck tension.

 

[Rsadams]

Possibles: 1/Bedding issue due to barrel heat 2/ a common malady to SR BR group shooters....one tends to get excited after producing a group in the zero's or low ones and tends to jerk the trigger (or some other shooting form mistake) in order to beat the conditions on the last shot in an attempt to preserve a possible record or win small group award. 3/ barrel mirage -use a mirage shield 4/ Allowing a round to sit in the chamber too long allowing the chamber to transfer heat to the powder through conduction -aka "cooking a round in the chamber".

+1on this... I am bad about doing this and loseing concentration on the last shot on a good group... But as others stated theres tons of reasons why.. But lack of concentration is a bad habit that's hard to break.. I would try better shooting habits first, it doesn't cost anything to see if thats the problem..

 

[Brians356]

Thanks a bunch. I had never thought of the cooking the round thing. I usually try to wait until I am ready to fire but I don't do it every time. I should have thought of that. I figured it was a huge chance on the human error I just thought I could get a few ideas on some other possible causes.

Ambient temperature changes drastically from summer to winter where I live. It occurred to me a long time ago that setting my loaded rounds out in the open didn't make sense, especially in winter. So now I use two shirt pockets to "stage" my test group rounds. If I'm loading 4 rounds at each setting (powder charge, seating depth, etc) I will take two groups of 4 out of the cartridge box and put the first group in one shirt pocket (the "shoot-from" pocket), and the next group in another pocket (the "on deck" one.) If it's cold enough for an outer jacket or coat, these shirt pockets are inside the outer garment, and will settle at a fairly constant temperature, moderated by body heat, even if it's bitterly cold outside. I will let the initial two groups' temperatures settle in the pockets for, say, five minutes. Then it goes like hitters in baseball:

I shoot the #1 group from the "shoot-from" pocket, then transfer the #2 group from the "on deck" pocket to the "shoot-from" pocket, and transfer a new group (#3) from the cartridge box into the now-empty "on deck" pocket. Etc. In this way I'm shooting rounds which are all roughly body temperature when I load them into the chamber, after spending time in two successive pockets between the cartridge box and the chamber. And I always shoot from the same pocket, so I don't get mixed up by alternating pockets.

There's still the problem of varying rifle chamber temperature. The very first shot out of a cold gun can't be avoided, but you can use "sighter" or "fouler" rounds to try to avoid this "start-up" cold condition. Once you get the rifle warmed up, if you don't shoot your test rounds too quickly, you can keep the chamber within a reasonably narrow temperature range. Combined with having the rounds themselves within a narrow range (using body heat), it's possible to mitigate the cartridge temperature variability to a large extent. You do need to pace rate of fire based on case capacity and how quickly your rifle heats up. In winter you could put the rifle in a relatively warm truck cab between sessions, to avoid it dropping to ice cold again.

I do get funny looks from fellow shooters when I reach into a shirt pockets to fish out rounds to shoot, and transfer groups from one pocket to another, etc. But whoever said accuracy shooters are not eccentrics?
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[gambleone]

Interesting. First I heard of this. Thanks for sharing.

 

[fguffey]

I will usually shoot a 4 shot group with some test loads. I have noticed that on more than one occasion I will have 3 rounds make one hole and the 4th round will be 1/4" to a 1/2" off.

I would apply the 'leaver policy'; meaning I would leaver the way I found-er. And then there is that thing with 4 rounds; When I test a rifle to determine if is worth keeping and or building I load 10 round groups in 12 different loads, bullets and powder charges and different weight bullets.. I know that makes no sense to anyone but I want 10 hole groups and I do not want the groups look like shotgun patterns. Put another way I want to know what happens to shot number 5 and number 6 etc.

F. Guffey

 

[M14AMU]

Keep your vision focused on the apex of the crosshair at shot break!! NOT the bullet hole!

 

[M14AMU]

I would apply the 'leaver policy'; meaning I would leaver the way I found-er. And then there is that thing with 4 rounds; When I test a rifle to determine if is worth keeping and or building I load 10 round groups in 12 different loads, bullets and powder charges and different weight bullets.. I know that makes no sense to anyone but I want 10 hole groups and I do not want the groups look like shotgun patterns. Put another way I want to know what happens to shot number 5 and number 6 etc.

F. Guffey

I want to know where shot #1 goes....all the time!