Reading group shape and bullet holes

[Tim Singleton]

I wanted to share some pictures of a recent match and talk about reading group shape and reading the shape of bullet holes. 6mm ppc at 100 yards with 65 grain bullets
This first target I tested. 3 loads during the morning warm up match and 30 grains of 133 dotted up nice. So I went with it to the record group. All was going great UNTIl the fourth shot and crap it jumped way out!
The load was too hot causing the proverbial 4 and 1. Take a close look at the bullet hole on the high shot. The bullet hole is oblong the bullet is not stable
On to target number two I incorrectly chose the light 29.3 load and the group went completely flat.
Dang! too light the holes are now nice and round tho
Target number three up in powder to 29.7 now we are getting close But, I need the vertical out. I know I can’t go up in powder or it might spit one out
Target number four left the load at 29.7 and went out in seating depth .002 Bingo! Finally there
Last target load stayed the same another nice group

The only problem is it took too long for me to get in tune all over but the crying.
I’m now on the tune tho and things went much better the rest of the match

 

[Tim Singleton]

I’ve only been doing this for 10 years maybe in another 10 it won’t take me three target to get things going
LOL

 

[CJ6]

It's good to see the thought process and the results of those actions.

 

[BoydAllen]

In the last year or so a friend has been shooting tuners (Harris) on his rifles. During that time we have gone over virtually every group. Based on that experience, I would say that he could easily adjust the vertical out of your third target, possibly with less uncertainty than guessing at charge weight adjustment. I am pretty sure that most would rather have a small amount of vertical than a four and one. I believe that Boyer has spoken of tuning for agg. protection.

 

[Tim Singleton]

In the last year or so a friend has been shooting tuners (Harris) on his rifles. During that time we have gone over virtually every group. Based on that experience, I would say that he could easily adjust the vertical out of your third target, possibly with less uncertainty than guessing at charge weight adjustment. I am pretty sure that most would rather have a small amount of vertical than a four and one. I believe that Boyer has spoken of tuning for agg. protection.

Agree on a lot of what you say. Problem is a 220 tune won’t win !

It is possible a tuner would have taken that dab of vertical out. I have several Harris tuners
But I have sworn off them this year. Back to basics of tuning for me!
There isn’t anything you can accomplish with a tuner that cannot be accomplished with seating depth and powder

 

[Tim Singleton]

@BoydAllen one problem for me with a tuner
Let’s say I had preloaded for a match with a normally stabile load of 30 grains that was too hot on match day. The tuner won’t help a too hot load. You’re stuck twisting that thing all over the place trying to get it out and can’t. Now your really lost

 

[BoydAllen]

@BoydAllen one problem for me with a tuner
Let’s say I had preloaded for a match with a normally stabile load of 30 grains that was too hot on match day. The tuner won’t help a too hot load. You’re stuck twisting that thing all over the place trying to get it out and can’t. Now your really lost

...unless you have done an experiment duplicating that situation during practice.

A friend was starting out in benchrest, a couple of years before COVID. For some reason he chose LT32 to work with. I suggested that on a day just before the match that he show up early and stay a little later than the matches would run, and retune as the temperature increased throughout the day. He did that and found that decreasing his load by .2gn. twice kept him in tune pretty well.

The next trick that I tried to get him to do was to copy Tony, by bringing several complete sets of loads to the line for the first group of the mornings agg. and test on the sighter to choose which one to use on his record target. I felt that with that kind of start and knowing his increments, that he could improve his results.

Unfortunately COVID came along, he quit, and did not come back.

One of the last events that he shot was an all five shot unlimited weekend that he won.

He had two real advantages, a talent for reading flags, and not getting too emotional during a match.

Getting back to my other friend and his Harris tuners, He has found that his nodes are wider with the tuners and for matches in the spring and fall (with relatively small temperature swings) , shooting 30.4 of recent 133 he has been able to come preloaded and not touch his tuner. To deal with that pressure, without risk to pockets he switched to Alpha brass. He does wear a belt and suspenders, so to speak, taking his loading equipment to matches, even when preloaded.

 

[Tim Singleton]

I will post photos and go through the Heavy varmint match tonight.

This doesn't need to turn into a tuner thread.

I'm just trying to share my experience shooting a recent match, going over each target and what I was thinking as it happened. The things I changed and the results on the target

 

[Tim Singleton]

Another comment on the targets above.
The reason it is so important to have the rifle tuned as best you can shows up on target number 4 of the above
Remember we have upped powder to 29.7 on target number 3. So far the conditions had been mild thru targets 1,2 and 3
Target 4, I moved the seating depth out .002 and left the load at 29.7. Now there was a hard blow from the right. The mild conditions were gone. Notice where the group forms on target 4 compared to 3

One of the many good things Jack says is that just because you can shoot doesn't mean you have to!
For match 4. I waited as long as I dared and there was nothing but strong wind. I had to hold a little bit on every shot with the intensity of the wind going up and down.
I hedged a little bit on shot 4 and didn't hold as much as I should have, and it leaked out of the group a little to the left. Overall for a half an inch of push at 100 yards I was tickled to death to get out of there with a .159

The point is that the seating depth adjustment was the right call. If the rifle wasn't in perfect tune, I couldn't have shot that group holding for each shot with that hard a blow.
On target 5, I again waited as long as I could and got a decent condition to shoot. Still some wind but not like target 4. The group formed right under my aim point, with one shot leaking out to the left on a missed pickup. Happy with a 171 to end the match
The rifle is handling the strong wind well.

 

[JEFFPPC]

So it's never a poor wind call or poor bench manners. You shoot one group and you nailed it changing something or one bad group and you guessed wrong. What if you did not get a proper trigger touch that shot. Its always the gun. I know it's the short range way but then how do you account for those who preload and do well. I think there is some delusion involved. Is there value in trying to analyze groups and make a change? I belive there is but to be constantly changing I think just might show it's not working as you would like to think, plus your ignoring 2 very important factors, wind and bench manners. Over the course of a two day match climate conditions can certianly have a pretty good swing, group to group, not so much. Your assuming you always pick the right spot to aim, doubt it. Its the load so start guessing.

 

[EGBrown]

I wanted to share some pictures of a recent match and talk about reading group shape and reading the shape of bullet holes. 6mm ppc at 100 yards with 65 grain bullets
This first target I tested. 3 loads during the morning warm up match and 30 grains of 133 dotted up nice. So I went with it to the record group. All was going great UNTIl the fourth shot and crap it jumped way out!
The load was too hot causing the proverbial 4 and 1. Take a close look at the bullet hole on the high shot. The bullet hole is oblong the bullet is not stable
On to target number two I incorrectly chose the light 29.3 load and the group went completely flat.
Dang! too light the holes are now nice and round tho
Target number three up in powder to 29.7 now we are getting close But, I need the vertical out. I know I can’t go up in powder or it might spit one out
Target number four left the load at 29.7 and went out in seating depth .002 Bingo! Finally there
Last target load stayed the same another nice group

The only problem is it took too long for me to get in tune all over but the crying.
I’m now on the tune tho and things went much better the rest of the match

Thank you for this excellent explanation of reading your targets. Could you clarify to me about "went out in seating depth .002" Does this mean you made bullet longer or shorter by .002"? Thank you! Eric

 

[Tim Singleton]

Thank you for this excellent explanation of reading your targets. Could you clarify to me about "went out in seating depth .002" Does this mean you made bullet longer or shorter by .002"? Thank you! Eric

longer out of the case and into the lands

the thought was it liked a little more powder, but I was afraid any more powder would make it spit
So a little further into the lands might be what it needed, and it was

 

[Tim Singleton]

So it's never a poor wind call or poor bench manners. You shoot one group and you nailed it changing something or one bad group and you guessed wrong. What if you did not get a proper trigger touch that shot. Its always the gun. I know it's the short range way but then how do you account for those who preload and do well. I think there is some delusion involved. Is there value in trying to analyze groups and make a change? I belive there is but to be constantly changing I think just might show it's not working as you would like to think, plus your ignoring 2 very important factors, wind and bench manners. Over the course of a two day match climate conditions can certianly have a pretty good swing, group to group, not so much. Your assuming you always pick the right spot to aim, doubt it. Its the load so start guessing.

As we go on into this two day match. Maybe I can answer some of these question

The first 3 targets clearly show an in and out of tune rifle. You are an experienced guy Jeff you can see that

Im not knocking anyone's method pre load or not

Just sharing my experience TRUST ME PLENTY OF POOR WIND CALLS TO COME
I plan to go over the whole match and show all target good bad and ugly

 

[ShtrRdy]

Tim -- I'm curious how much 'jam' you're ending up with from Touch Point?

 

[Tim Singleton]

Tim -- I'm curious how much 'jam' you're ending up with from Touch Point?

from the stripped bolt method of feeling the touch point, this barrel was about 020 in
With my bullet, reamer and bushing 025 is full jam before push back happens

 

[EGBrown]

from the stripped bolt method of feeling the touch point, this barrel was about 020 in
With my bullet, reamer and bushing 025 is full jam before push back happens

Thank you

 

[gunsandgunsmithing]

I wanted to share some pictures of a recent match and talk about reading group shape and reading the shape of bullet holes. 6mm ppc at 100 yards with 65 grain bullets
This first target I tested. 3 loads during the morning warm up match and 30 grains of 133 dotted up nice. So I went with it to the record group. All was going great UNTIl the fourth shot and crap it jumped way out!
The load was too hot causing the proverbial 4 and 1. Take a close look at the bullet hole on the high shot. The bullet hole is oblong the bullet is not stable
On to target number two I incorrectly chose the light 29.3 load and the group went completely flat.
Dang! too light the holes are now nice and round tho
Target number three up in powder to 29.7 now we are getting close But, I need the vertical out. I know I can’t go up in powder or it might spit one out
Target number four left the load at 29.7 and went out in seating depth .002 Bingo! Finally there
Last target load stayed the same another nice group

The only problem is it took too long for me to get in tune all over but the crying.
I’m now on the tune tho and things went much better the rest of the match

Hey, we agree on one thing at least...Reading groups is key!
I find these results remarkably similar to yours and see how it repeats?
Not being a tuner thread, I covered the numbers and replaced them with yours. Lol! Pretty remarkable coincidence? No sir.

 

[wvlongshot]

Thanks for doing this. Newer lot of 133?
I'm struggling with 133.

 

[Tim Singleton]

Thanks for doing this. Newer lot of 133?
I'm struggling with 133.

yes 2024 its pretty good stuff!

 

[JEFFPPC]

As we go on into this two day match. Maybe I can answer some of these question

The first 3 targets clearly show an in and out of tune rifle. You are an experienced guy Jeff you can see that

Im not knocking anyone's method pre load or not

Just sharing my experience TRUST ME PLENTY OF POOR WIND CALLS TO COME
I plan to go over the whole match and show all target good bad and ugly

Tim, I think what your explaing has some validity. But I think the vast majority of shooters do not have the experience to read and adjust in a meaningful way but they get fixated on what the Big Guys are doing and end up looking their way in the weeds, I see it not a science but hopefully experienced guessing. Just from looking at what is online I believe a majority of shooters think it's all about the gun and end up ignoring other major basics. I I think a big percentage of shooters do not have a process when it comes to load development and pay little attention to conditions and bench manners especially during load development. Thanks for sharing your targets and thoughts, I will follow and hope to learn from them.