tuning by group shape

A

afrench

Member
i've been shooting short range BR for a few years now and am slowly improving my aggs.

one thing i still struggle with is figuring out what the target is telling me and how to adjust for the group's shape. this target was shot this last weekend at a club match.

for this target, the wind was probably 15+ from 5-7:00 with fast switches. high clouds with virtually no mirage to deal with. it was cool and humid. i shot this group with wind from 5:00.

let's say i was using a typical 133 load, 29.0gr, 10 thou into the lands, hard neck tension, etc. what changes would you make to tighten up the group?

or, if you're more comfortable with a different powder/charge how would you make adjustments if you were using your pet load in your gun?



and the sighter...

 
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Looks like wind to me

Certainly, I've shot a few targets that looked similar. One question before I say more - how long (time) between shots?
 
Refer to Jack Neary's You tube videos

Looks wind sensitive. More powder. As long as your not showing any signs of over pressure. Good luck. Tony
 
Looks like you're missing the wind intensity. Your directional hold looks good. With changes like that I'd probably be looking to take more sighters. Your might try and give more attention to your tails, but at 15 + they may be straight out anyway. Seems to me sighter shots would help the most.

Rick
 
Wilbur said:
Certainly, I've shot a few targets that looked similar. One question before I say more - how long (time) between shots?
Click to expand...

Wilbur,

it seems like i could only get about 2 off at a time before a drastic wind change. the angle would change quickly but would usually return quickly too. i probably took 60 secs to shoot the group.
 
I would recommend you try this technique. Tune your rifle as best as possible. Now intentionally take it out of tune by increasing the load by say 3 tenths at a time until you reach your upper limit. Also do the same thing by decreasring the load by 3 tenths until you reach your lower limit. Now you can see for yourself how the groups form as the gun is going in and out of tune.

Bart
 
tzander said:
Refer to Jack Neary's You tube videos
Looks wind sensitive. More powder. As long as your not showing any signs of over pressure. Good luck. Tony
Click to expand...

Tony, i've watched them a few times but not recently. i need to watch again.

after shooting the above target, i couldn't explain the shot that dropped down. so, i went up .3 and shot this one.

two things helped here. i increased the charge and i was able to get the entire string off at one time, probably in about 20 secs.

 
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Greyfox said:
Looks like you're missing the wind intensity. Your directional hold looks good. With changes like that I'd probably be looking to take more sighters. Your might try and give more attention to your tails, but at 15 + they may be straight out anyway. Seems to me sighter shots would help the most.

Rick
Click to expand...

Rick,

yes, i was missing some intensity changes but that gets a bit challenging to read when the tails are hanging straight out. there are some guys that can read the tails with the wind screaming but i'm not there yet.

as far as the sighters, or lack there of, i was just screwing around with 133 since i haven't shot any of it since early last year and was running low on powder and bullets. plus with the directional changes happening as fast as they were, i'm not sure more sighters would have helped that much.
 
Bart said:
I would recommend you try this technique. Tune your rifle as best as possible. Now intentionally take it out of tune by increasing the load by say 3 tenths at a time until you reach your upper limit. Also do the same thing by decreasring the load by 3 tenths until you reach your lower limit. Now you can see for yourself how the groups form as the gun is going in and out of tune.

Bart
Click to expand...

Bart, i definitely need to spend more time with 133. i went away from it about 2 years ago thinking it played a part in some random flyers. turns out i had rear bag and rest setup issues, bad bench manners, etc. going on... funny how powder, bullets, barrels all get blamed for bad groups when it's really the idiot pulling the trigger!!
 
I tried this with LT-32. I started at 29.7 all the way down to 28 grains. The loads that were obviously too hot would have a popped shot out of the top of the group (normally). Then the groups would go a little vertical and then into nice tight groups. When the powder charge was too low the groups would triangle and then go gobby!


That's what I saw.

Bart
 
Years back, I remember that Skip Otto used a dual ribbon setup to deal with wide variations in wind velocity. He used a lighter one at the rearmost position, and in front of it, along the bottom of the vane, was attached a heavier one, that was for when the lighter one had gone horizontal. It was made of a half dozen strands of the heaviest black yarn, knotted together about every six inches. This is from far enough back that I may have gotten some of the details wrong, so if you have some information, please chime in.
 
Has anybody

taken a wind meter by one their wind flags to calibrate what the tails are showing? Surely someone has tried this by now with all the gadget lovers this sport has.
 
adamsgt said:
taken a wind meter by one their wind flags to calibrate what the tails are showing? Surely someone has tried this by now with all the gadget lovers this sport has.
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Yes, sort of. I used a couple of Gene Beggs wind probes along with Graham flags for a season or two. What I could see was that even though you had constantly straight tails the wind speed, according to the probes, might vary as much as 50%. The actual wind speed isn't important. Using the attitude of the tails with what the sighters tell you seem to be the important thing. When the wind is in a hard blow, I have found it best to wait things out. It's unusual, in my experience, that you get a hard blow for the full relay. Almost always, you will get a break, but you have to be patient and wait for it. If you never get a break you are no worse off for waiting. The target that the OP posted didn't look out of tune to me at all. In fact, assuming the 5 o'clock wind, it looked like it was in perfect tune. But that's just me. I stopped using a combination of flags and probes because the FOV just got too busy, but they will show you what's going on.

Rick
 
Bart said:
I tried this with LT-32. I started at 29.7 all the way down to 28 grains. The loads that were obviously too hot would have a popped shot out of the top of the group (normally). Then the groups would go a little vertical and then into nice tight groups. When the powder charge was too low the groups would triangle and then go gobby!


That's what I saw.

Bart
Click to expand...

thanks Bart. that's the kind of feedback i was hoping to get... generally speaking, when it's too hot it does this, too low, that. when you're too far in the lands, this, too far out that, etc.
 
afrench said:
i've been shooting short range BR for a few years now and am slowly improving my aggs.

one thing i still struggle with is figuring out what the target is telling me and how to adjust for the group's shape. this target was shot this last weekend at a club match.

for this target, the wind was probably 15+ from 5-7:00 with fast switches. high clouds with virtually no mirage to deal with. it was cool and humid. i shot this group with wind from 5:00.

let's say i was using a typical 133 load, 29.0gr, 10 thou into the lands, hard neck tension, etc. what changes would you make to tighten up the group?

or, if you're more comfortable with a different powder/charge how would you make adjustments if you were using your pet load in your gun?


and the sighter...
Click to expand...



You have bigger problems than powder charge tuning................look at the impact differences between sighter and record targets, until you fix this impact difference between the 2 targets you will never be competitive no matter how well you tune the powder charge, something is most likely wrong with your rest/bag setup and/or firing procedure.
 
One other thing, might want to double check whether or not you have a good seating depth. The single hole on the target (first target) amd the single hole on the sighter are oblong and the ring around the hole isn't even. Sure sign of seating depth being off a little. This will make a load more wind sensitive.

You sure have received a bunch of good advice on this thread, from some of the best shooters out there.

Hovis
 
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