Understanding groups and what to do next

[DLT]

I have been on a roll with pretty active posts. I have one more, I want to learn how to read groups during load development to point me in right direction as to what to do next. I have read several posts on here where the poster has shot a group and it’s verticle and people will chime in and immediately say up the charge and a couple will say inconsistent pressure on the stock. Let’s say the rifle is in good shape, the scope is fine, the rest/bag setup is fine your form is good, and no problems on the reloading benchand have a verticle group what do you do ? Same with a straight horizontal group ? What could fix that providing you did not pull and zero wind. What causes 2 shots side by side and 1 kicked out be it a little or a lot. The same with small triangles and cloverleafs which what we like to see but what if you shoot a big triangle ? Many questions but maybe I can learn something

 

[Dave Way]

As far as reading groups, I like to shoot a target with multiple targets on the paper. See the attachment. Sinclair makes the target I attached. I shoot a series powder charge of test groups. Assuming you have an accurate rifle, you will see where the groups not only change shape but you will also see where the point of impact wanders. You should also see where several consecutive charges print in pretty much the same spot. Choose not only a tight group but also one in an area where POI doesn’t shift too much. In this case, 30.7 shot tight and 30.5 and 30.9 printed pretty much in the same area. The next step would be to re-shoot the 30.5 to 30.9 area at 0.1 grain increments.

Just how I tune a rifle at 100 yards. Hopefully it helps.

Dave.

 

[DLT]

As far as reading groups, I like to shoot a target with multiple targets on the paper. See the attachment. Sinclair makes the target I attached. I shoot a series powder charge of test groups. Assuming you have an accurate rifle, you will see where the groups not only change shape but you will also see where the point of impact wanders. You should also see where several consecutive charges print in pretty much the same spot. Choose not only a tight group but also one in an area where POI doesn’t shift too much. In this case, 30.7 shot tight and 30.5 and 30.9 printed pretty much in the same area. The next step would be to re-shoot the 30.5 to 30.9 area at 0.1 grain increments.

Just how I tune a rifle at 100 yards. Hopefully it helps.

Dave.

View attachment 1460124

Thanks for that. I know what to look for as far as what’s the sweet spot but I’m not sure on what to do to get there if a rifle isn’t shooting as good as yours such as if a group was verticle or horizontal or 2 in 1 with one shot set out. Like how do you know if you need to up the charge or lower it or change seating depth or bullets or power or both.

 

[Andy Work]

5-Shot-Group Shapes: Here's What They're Telling You

 

[Straightshooter1]

Thanks for that. I know what to look for as far as what’s the sweet spot but I’m not sure on what to do to get there if a rifle isn’t shooting as good as yours such as if a group was verticle or horizontal or 2 in 1 with one shot set out. Like how do you know if you need to up the charge or lower it or change seating depth or bullets or power or both.

Maybe taking a look at some Jack Neary videos might help you some:

 

[Zero333]

If you look @Dave Way picture... 30.7 gr not only is small, but the 3 charge weights before it and the 2 after it have the same Point Of Impact. This is a very steady load over a certain range of temperatures (if using a temp stable powder).

When I work up a load, I do the same charge weight test as Dave, and I also shoot a Audette Ladder at 300 meters to try to correlate the 2 for Point Of Impact.
Meaning if Dave shot a Audette Ladder at 300 meters with the same charge weights, he should see the charge weights between 30.1 and 31.1 gr to be roughly in the same area and have nearly the same vertical. If all correlates I would also test 31.6 gr to see if it shoots as good as 31.7

The way you choose to test a load should depend on the discipline your shooting. My way of taking into consideration the Point of Impact is leaning closer to PRS type of shooting.
Dave's discipline is purely Bench-rest.

 

[17cal Fan]

Unless you are shooting a bolt gun 30/30 the forearm position on the front rest can screw with you more than you think. Consistency is everything. Rest it closer to the receiver and do not touch the barrel in your hold. I have held the forearm down by reaching around to the front of the rest but only touch wood. What happens after the trigger is pulled and before the bullet leaves the barrel is amazing to realize/evaluate especially with shorter barrels. I've only been scope eyed once or twice in my life and didn't enjoy it. 30/30 has that ability so hold but be consistent and careful. Just for food for thought.

 

[JFrank]

Seating depth (can) make a bit of a difference in group shape as well.

Thanks for that. I know what to look for as far as what’s the sweet spot but I’m not sure on what to do to get there if a rifle isn’t shooting as good as yours such as if a group was verticle or horizontal or 2 in 1 with one shot set out. Like how do you know if you need to up the charge or lower it or change seating depth or bullets or power or both.

 

[Murray Brook]

@Straightshooter1
Did Jack mention what weight bullet he was testing or did I miss that.

 

[Bill Norris]

@Straightshooter1
Did Jack mention what weight bullet he was testing or did I miss that.

Not certain if he references the actual bullet weight but the 68 gr. is the one most BR shooters use.

 

[Bill Norris]

Thanks for that. I know what to look for as far as what’s the sweet spot but I’m not sure on what to do to get there if a rifle isn’t shooting as good as yours such as if a group was verticle or horizontal or 2 in 1 with one shot set out. Like how do you know if you need to up the charge or lower it or change seating depth or bullets or power or both.

Other than taking note of Jack's video info you would have to re-test the areas that show the most promise.

 

[Straightshooter1]

@Straightshooter1
Did Jack mention what weight bullet he was testing or did I miss that.

I don't really recall, but I think it's probably a 67 gr bullet that he's used in the past:

New World Record by Jack Neary

Team Lapua member Jack Neary established a new (confirmed) World Benchrest Shooting Federation world record on Saturday in the Heavy Varmint 200 yd. rifle class, with a 5-shot group measuring .110″

www.lapua.com

 

[Ccrider]

There are no short cuts for what you are looking for. Is it you? Is it the load? Is it the rest bag setup or tracking issues? Is it wind? Could be any one or any combination.
The more you do it, the better you get at figuring out what the gun and load is telling you.