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View Full Version : 4 and 1 out of the bottom by 1/2 inch. Wha hoppen?



Roy Allain
09-10-2013, 02:35 PM
This past Friday at the range I started to rip out my hair and I don't have any to begin with.

My last group out of ten. A very small group 4 (.141) and then the very last shot. It dropped out of the group 1/2 inch below, straight down (6 o'clock). I'm happy that there were no children there. Wow. Such language.

I had a couple of other groups with explanable flyers, "it's the wind stupid", I keep telling myself. But not this one. Pretty calm winds, less than 3 mph, left to right. No down drafts, shear, etc.

The only possibility I can think of is I had to have bumped the rear bag with my right arm or chest. Somehow.

Any ideas.

Many thanks,

Roy

abintx
09-10-2013, 04:56 PM
This past Friday at the range I started to rip out my hair and I don't have any to begin with.

My last group out of ten. A very small group 4 (.141) and then the very last shot. It dropped out of the group 1/2 inch below, straight down (6 o'clock). I'm happy that there were no children there. Wow. Such language.

I had a couple of other groups with explainable flyers, "it's the wind stupid", I keep telling myself. But not this one. Pretty calm winds, less than 3 mph, left to right. No down drafts, shear, etc.

The only possibility I can think of is I had to have bumped the rear bag with my right arm or chest. Somehow.

Any ideas.

Many thanks,

Roy

Go to any match and you'll hear similar statements, left and right in the line, all day long. Got and Uppy/Downy flag [ http://www.brflags.com/flags.html scroll down] to tell you if a down draft or shear was actually present? I've got one, and have seen it either go up or stay down for as long as 10 to 15 seconds. Also, calm winds aren't always what they seem. Good luck.

SGS
09-10-2013, 07:29 PM
The only possibility I can think of is I had to have bumped the rear bag with my right arm or chest. Somehow.

Were you shooting heads up? Is there some reason that all the usual suspects such as case, powder, primer, rifle, etc. can be positively ruled out?

I have a barrel that for the past 3 years was the best I have ever had, certainly as close to being a Hummer as anything I have ever seen. Now that it is getting to the end of it's best accuracy, it throws a shot out of the group regularly. If they go left or right it is easy to attribute to conditions, but when they go out the bottom or the top for no apparent reason, I'm left to Gnash my teeth and mumble under my breath.

Scott

mks
09-10-2013, 07:59 PM
Roy,
So many possibilities, but if you are shooting ones, I should be seeking your advice instead of the other way around. I do know that after tweaking firing pin fall, my number of unexplained flyers went from 1 in 10 to 1 in 40 or 50. I am also beginning to think that one of the signs that the rifle is going out of tune is that a flyer appears. I would be interested to hear from those with more experience with tuners. I wonder if it's possible to go through an entire match without a flyer or two.

Cheers,
Keith

JerrySharrett
09-10-2013, 08:18 PM
Roy, sorry to say this but many times the last shot going out of a tiny group is a "choke". The others went in easy and the shooter just simply lets up the "must do alike every shot" routine that got you there.

Now tell me, I am loosing the 2nd or 3rd shot and the last ones go in??? 95% of the ones I am loosing go to the right...by a bunch!!!

zippy06
09-10-2013, 08:30 PM
Bug.



too many insects this year.

skeetlee
09-10-2013, 09:31 PM
I always hold a little high on my last shot. Seems to work for me. Not 1/2" high, but a little high. Maybe your load is a little hot???? I wouldnt know! Lee

DeltaBravo
09-11-2013, 09:16 AM
I usually have exactly the opposite problem. One goes into a bug-hole and the other 4 are out on their own!

Dennis

goodgrouper
09-11-2013, 11:47 AM
All I can say is WELCOME TO BENCHREST!:D

Wilbur
09-11-2013, 11:50 AM
Let's talk about the explained flyers. Are you reaching for an explanation? It's very typical for a rifle to shoot very very well - if not for the flyers. Explain them if you wish but you can't do anything about them except fix the rifle.

mks
09-11-2013, 04:41 PM
Let's talk about the explained flyers. Are you reaching for an explanation? It's very typical for a rifle to shoot very very well - if not for the flyers. Explain them if you wish but you can't do anything about them except fix the rifle.

An explainable flyer that can't be fixed by working on the rifle is, "Oops, I missed that switch!":o

afrench
09-11-2013, 04:42 PM
there are lots of things that can cause unexplained shots but i'll tell you about one that happened to me earlier this year.

i've been having a noticeable problem with vertical in my groups for a few matches until it got real bad during a club match. i had 1 or 2 shot drop out of the group by a lot, like .4-.6 inches at 100. on one of the shots, i noticed that the firing pin wasn't cracking cleanly for about 1 out of 5 shots.

so, i took the trigger apart when i got home and found a gunky, greasy spot on the inside of both plates where the firing pin block rubs. it was just enough gunk to cause erratic ignition. after cleaning, the trigger/firing pin sounded correct again and the huge vertical problem went away.

expiper
09-11-2013, 06:59 PM
Roy,,,did you set the ctg case aside that "threw" that shot,,,,it could have neck tension problems,,,crack in the neck ,etc,,,,anytime I have a shot jump wayyyy off like that I save that case and load it again and use it as a sighter after a shot or two and see if it goes up/down/sideways again,,,If so I toss it,,,,but if you didnt cull it out it is in the box with all the others waiting to bite you again,,,and be un-eplained "again" !!!....how many times have you loaded the ctgs,,,how much neck tension,,(usually not enuff) will allow case anomolies make a lot of difference ,,,Roger

zippy06
09-11-2013, 07:59 PM
Rodger might be the winner here.
I once tried an experiment. Mostly cause I brought along some worn out cases. And not enough newer cases.....
4 cases from one box and 1 from another box. Shooting a good green at Holton. 200y. Mirage and all.
4 in a nice little group. Small 2. One by itself.
Did it again. Same results. Same conditions.
4 at 3:00 on the 9 ring and 1 on the 8 ring. Same small hole at the 9 ring.
The one odd ball seamed a little loose in the neck. But, not by much....
Nice test.
I now have a bunch of 20 round boxes every where.....

Zdog
09-11-2013, 08:34 PM
This past Friday at the range I started to rip out my hair and I don't have any to begin with.

My last group out of ten. A very small group 4 (.141) and then the very last shot. It dropped out of the group 1/2 inch below, straight down (6 o'clock). I'm happy that there were no children there. Wow. Such language.

I had a couple of other groups with explanable flyers, "it's the wind stupid", I keep telling myself. But not this one. Pretty calm winds, less than 3 mph, left to right. No down drafts, shear, etc.

The only possibility I can think of is I had to have bumped the rear bag with my right arm or chest. Somehow.

Any ideas.

Many thanks,

Roy

Roy - it could be a handling error. I have a HV Score gun which I shoot about 1/2" off my shoulder and "pinned," i.e., fore end against the front rest stop . Once in a while - especially if I'm rushing shots - I don't push the rifle all the forward. Just before it goes off I automatically lean in slightly to catch the butt on my shoulder. But since it (the butt) is closer than it should be - I bump it pushing it forward which raises it, causing the shot to go low. Oh - when I say pinned - I don't mean jammed against the stop - just lightly touching . . .

Zdog (Chris Mitchell)

Bill Dorsey
09-13-2013, 12:43 AM
Check your scope....I got tired of the 4 and 1s and the 3 and 2s.


I held the rifle steady and tapped on the turrets with a screwdriver handle and watched the cross hairs jump 3/4 inch to the right after 3 or 4 hard taps.


Sent the culprit scope home with Cecil Tucker for a fix and my rifle started shooting again.

Wilbur
09-17-2013, 01:05 PM
Wayne Campbell screwed the barrel off his Panda, grabbed a dead blow hammer and drove it muzzle down into the ground in front of my bench at Rockingham. I snatched it up for two reasons. Wayne is a bit impulsive (understatement) and I was sure he would want it back when he came back down and if he didn't...I did.

He stated that he didn't want it back and offered me his hammer to replace the barrel as a gesture of good faith. I wasn't having any part of that so I cleaned it out and shot it for a couple of matches. That was the most amazing barrel I ever witnessed. It would put four into a scary hole and throw one into the next county. I'm talking "hole not getting bigger" for three and often four. One time, the flyer blew back in and I got small group.

The point of this is to re-state my earlier, somewhat nebulous, post where I was trying to convey that some barrels will just do this and will continue to do it until you abandon the barrel. This barrel is the worst nightmare available to benchrest competitors. Hold on..the second worse...the worst is the same situation but caused by the rifle.

zippy06
09-17-2013, 07:22 PM
Wayne might have screwed that barrel on to a BAT.
I sat next to Wayne at Holton. IBS Nat.
We had a lot of 4 and 1 or 3/2. His were smaller than mine. Which was a small comfort....
That's where the bug comment came from. The weeds needed a trim. It was a jungle. With snakes, frogs, turkeys, and whatever.......
Even with a green field and 10" weeds the mirage was fun to watch. :rolleyes:
I have seen it worse. When you can't see your holes......:(
Tim

Charles E
09-18-2013, 08:14 AM
Wayne might have screwed that barrel on to a BAT.

No, the story Wilbur told is sort of legendary at Rockingham, a tough place to shoot. Lot's of naturally occurring 4 and 1s as well.

I beleive it had a coda, which may or may not be true... Wilbur took the barrel off, gave it to another SER shooter -- maybe Roy Darnell? -- who cut an inch off the muzzle and had a good barrel. It no longer threw a shot, but it also no longer put them into a tiny little hole. This was long before tuners made an appearance. Or maybe he cut an inch off the back & rechambered, or maybe this part is just myth.

The real "rest of the story" is Wayne learned to throw his ear muffs rather than to pound barrels. Much cheaper.

Roy Allain
09-18-2013, 02:07 PM
Roy, So many possibilities, but if you are shooting ones, I should be seeking your advice instead of the other way around.Cheers, Keith

The ones are few and far between.

Roy

Roy Allain
09-18-2013, 02:12 PM
Hey Roy:
The northern tomatoes are great this year and right now.

Are you running your shots or picking?
You may be allowing that last round to cook in the chamber as you ponder the 4 and 1 dilemma. If it is always the fifth that goes low, it is probably driver error of one sort or another. Check out your table manners on every shot and not just the fifth. As I once told Majewski when he was having the same problem, shoot the fifth shot first.

No, it was just this one. I have a couple of other flyers, but I know the wind caught them. This one, I just don't know, but I think I bumped the back of the rear rest somehow. This Friday at the range I will check my position(s) and see what goes. I'm thinking that I might have to raise my seat.

Roy