Going from Sighter to Record bull..

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eww1350

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I have been experiencing a problem when going from the sighter to the record bull (group shooting with a 6ppc))..
I usually fire a couple of foulers then pick a condition and fire several sighters to see if the condition will let all the shots cluster...
When I go to the record bull my first shot will not be close to the impact spot on my sighter...
Especially at 200 yds it is a killer...because the 2nd thru 5th shots will be near or on the original impact point I saw on my sighter...
I use a "joystick" type front rest..
In a recent match I was so frustrated..I fired one fouler round over the target frame and fired 5 shots for record without going to the sighter bull...the 5 shots all stayed together..:confused:
I finished the match (2 targets) using the no sighter method, and all went much better...
Mike Ratigan referenced a similar problem in his book..
What causes this phenominon..???
 
eww1350 said:
I have been experiencing a problem when going from the sighter to the record bull (group shooting with a 6ppc))..
I usually fire a couple of foulers then pick a condition and fire several sighters to see if the condition will let all the shots cluster...
When I go to the record bull my first shot will not be close to the impact spot on my sighter...
Especially at 200 yds it is a killer...because the 2nd thru 5th shots will be near or on the original impact point I saw on my sighter...
I use a "joystick" type front rest..
In a recent match I was so frustrated..I fired one fouler round over the target frame and fired 5 shots for record without going to the sighter bull...the 5 shots all stayed together..:confused:
I finished the match (2 targets) using the no sighter method, and all went much better...
Mike Ratigan referenced a similar problem in his book..
What causes this phenominon..???
Click to expand...

What did Ratigan say to do about this situation?............Don
 
Chuck..I am using a Protektor "rabbit ear" bag with Cordura ears and heavy sand..single row stitching..(stock is a Bruno/Mcmillan)...

Don...Page 236 in Mikes' book.. "There are two kinds of shooters, those who have this problem, and those who have this problem and don't realize it.."
 
I never move my toggle rest 'down' to the poa. If I move the poa too high I then go back low and work my way back up.
 
eww1350

there's no remedy.... just hold as Mike said in his book and repeat also to me at the SS , havin' had this problem a couple of time during the match.

my 0.02 euro cent
GLF
 
I had this to happen to me several times at the Super Shoot. If my first record shot didn't go where it should I then chased it....usually very successfully if the condition didn't go nuts on me.
 
I sure am no authority but I have noticed the same thing.

I found it helps a lot to work the rifle back and forth a few times and resettle it into the bags so that the forend isn't in a bind caused by the changed vertical position of the front bag. Of course trying to do that if you are up and down from the sighter to the record slows up proceeding.

It also seemed to help to lift the rifle way over the top of the record and drop back down, the sides of the front bag are forced further than needed and thus will relax a little as the stock is lowered again.

I am sure it helped when I switched to an Edgewood low height and low ear rear bag. The Kelbly stock drops into the ears deeper than the Protektor bag and the stock sits lightly on the main body of the bag with the weight supported mostly on the ears. Seems that would offer a less of a change in the contact when the stock pivots as you lift the front of the stock up going to the record. The stock actually rides a ridge at the back of the space between the ears so there is very little change in orientation of the stock on the rear bag.

Pack the front bag with normal course (ish) sand and the rear ears with normal sand and the rear bag body only with heavy sand. The ears will hold position better and not tend to collpase with movement.

One thing Ratigan does suggest, and one I found helped at least being aware of the problem related to how you set up your zero. It seems many set the zero up so a hold on the bottom of the mothball lets the bullet impact in the centre of the mothball. Mike suggests setting up with a top of the mothball hold so that if the bullet impacts even just a little high it is more obvious. Instead of the bullet being a little further from the crosshair it is a little closer (assuming the usual high hit) and thus it is now much closer to the crosshair or dot. The impact difference may not be any more but the relative position to the reticle makes it more obvious and thus easier to spot and easier to hold for.

Bryce
 
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eww1350 said:
I have been experiencing a problem when going from the sighter to the record bull (group shooting with a 6ppc))..
I usually fire a couple of foulers then pick a condition and fire several sighters to see if the condition will let all the shots cluster...
When I go to the record bull my first shot will not be close to the impact spot on my sighter...
Especially at 200 yds it is a killer...because the 2nd thru 5th shots will be near or on the original impact point I saw on my sighter...
I use a "joystick" type front rest..
In a recent match I was so frustrated..I fired one fouler round over the target frame and fired 5 shots for record without going to the sighter bull...the 5 shots all stayed together..:confused:
I finished the match (2 targets) using the no sighter method, and all went much better...
Mike Ratigan referenced a similar problem in his book..
What causes this phenominon..???
Click to expand...
One thing that may cause this is a hard and flat front bag. By this I mean you settle your forearm into the bags creating a flat contact point for the forend. When you first go up to the record, the forearm is resting on the edge of this flat surface and creates one type vibration of the gun. After the first shot, the gun settles and reshapes the same flat surface on the bag as you had at the sighter.

Rimfire shooters who shoot 25 shot score targets are especially aware of this. One thing you can do is to "crush the front and rear edges of the front bag, breaking up the hard flat. Then when you go to the record there is not as much of a hard flat.

Someone made a front bag, I still have one, that had a ridge sewed crossways to eliminate this but his bag created other problems.
 
simple fix to try

The front bag is much shorter front to back than the rear bag. The problem is the angular contact with the bottom of the stock on the rear bag. The highest part should be towards the rear which is backwards it seems, the way bags are made. Try it and you will have a much smaller problem with the transition from the sighter to the record. Working the gun helps some and the manner in which the rear bag is packed is a factor as well. You should experiment with the fill. Many people try to pack them too hard.
 
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Jerry's comments regarding the rear bag mirror what I mentioned above about changing to the Edgewood rear bag seeming to help. The stock sits on the ears but also kinda pivots on a stitched ridge that it sits between the ears at the rear. With the base packed quite hard it holds the middle up nice and firmly and lets the stock run lightly on that ridged area. Seems that would for a nice area for the stock to pivot around when rising the forend up and down on the front rest.
 
GLF said:
eww1350

there's no remedy.... just hold as Mike said in his book and repeat also to me at the SS , havin' had this problem a couple of time during the match.

my 0.02 euro cent
GLF
Click to expand...



I would have thought that Mike Ratigan would have included all the remedies in his book............maybe there are some things that are still not supposed to be discussed.

Well, this one seems small and innocent enough.

Remedy=..........Dryfire, no case in the chamber, one time, on the record target before starting the record group, using medium packed bag ears.

Dryfire, no case in the chamber, with medium packed ears...............very closely simulates the vibration pulse of a live fired round and will settle the sandbags in the same attitude as sighter target angles, thereby giving identical sighter and record impact points.....................................problem solved....................................Don
 
Don

i donno if Mike's book has all the remedys, but in a 10 years shooting benchrest, i've had this problem sometimes, and i've tryed all the possible remedy, unpack front sand bag that was supposed too hard, rear ears too stiff, so unload it just a bit, changing combo hight, material, waxed to silicone sprayed ecc....
i've found that a softer front bag solved it, in conjuncion of softer rear ears, this minimize vibration , but sometimes it happens again and the only thing to do is hold....

it happened to me only three times over 24 groups fired.

ps: obvious in a cross wind or light condition not in a head or tail wind....

GLF
 
GLF said:
Don

i donno if Mike's book has all the remedys, but in a 10 years shooting benchrest, i've had this problem sometimes, and i've tryed all the possible remedy, unpack front sand bag that was supposed too hard, rear ears too stiff, so unload it just a bit, changing combo hight, material, waxed to silicone sprayed ecc....
i've found that a softer front bag solved it, in conjuncion of softer rear ears, this minimize vibration , but sometimes it happens again and the only thing to do is hold....

it happened to me only three times over 24 groups fired.

ps: obvious in a cross wind or light condition not in a head or tail wind....

GLF
Click to expand...

Hi GLF,

3 out of 24 groups is not too bad.

Even with using dryfire on record, I might get 1-2 point of impact changes out of 20 groups, and those changes were much smaller than without dryfiring, maybe a 1/2 bullet hole difference, which than would have to be chased.

Some competition guns that I own actually act better to dryfiring than others, and one other method can be used to make even the difficult ones respond.............and that is to use a "blank/fireform" (full powder charge, no bullet, carboard or balsa plug) round as the first shot on the record target, but alot more trouble to prepare and use than the dryfire route...............................Don
 
Water in the bore

......just kidding.......

Borrow a rear bag. If that doesn't fix it then wait for it to go away.
 
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