Thread: 1 shot groups (cold bore challenge)

In many recent threads that have been about the concept of making decisions using larger amounts of shot data rather than smaller, there have been many comments that are variations on the theme of "I don't care about getting a zero or understanding of the precision capability of my rifle system based on larger data sets, I just care where the first shot goes".

This implies that
1) the first shot may go somewhere that isn't predicted by a larger dataset (I.e. group or groups overlaid) and
2) the first shot does go in the same place every time, or more so than groups would indicate.

I felt like testing this with my rifle system. Does the first shot from a cold bore tell me anything different to say, just banging out a 10 rd group ?

I've been taking the same target to the range every time I go shooting, and fire the first round of the day at it. Same shooter same rifle system, different conditions. Obviously breaking position quite significantly between shots.

I'm up to 7 days of this. So far, all 7 shots have fallen within a 24mm dot at 100m (about 0.8moa), .24MRAD.

The point of impact for all these shots so far falls within the footprint of a 10rd group fired all at once.

This isn't terribly surprising or enlightening. I'll continue shooting the same target each range trip, although it is in danger of falling apart, but I don't think there is a lot to learn from it with this rifle system.

It would be extremely interesting to see others do the same.


A 10rd group fired all at once - zeroed with 1 click left afterward.


7 rounds fired over 7 different range trips, 1 shot at a time - with the zero established with the 10rd group above.

Hi Gimp i like they way you think we - back in the ole days were taught to Aim Small Miss Small with a single shot
you most likely got off one shot only as there were no suppressor back then too
Thanks for putting your testing info up Cheers

Thanks Gimp that is great to see - really hope my rifle would / will do the same as yours, it would give a lot of confidence knowing its dead on at 100 from a cold bore ahead of dialing up.

Cheers

AMac

When you say cold bore. Is that bore clean or still fouled from previous sessions. Personally I have noticed that with all the rifles I regularly shoot (2 x .223 and 2 x 6.5CM) the first round through a cold, clean bore always has a slightly lower velocity than shots subsequently fired in the same session, around 30 fps. The POI at 100m doesn't seem to be affected but I guess the lower velocity would start to make a difference at longer ranges

Fouled, or lightly cleaned - not scrubbed back to bare metal.

Originally Posted by gimp

In many recent threads that have been about the concept of making decisions using larger amounts of shot data rather than smaller, there have been many comments that are variations on the theme of "I don't care about getting a zero or understanding of the precision capability of my rifle system based on larger data sets, I just care where the first shot goes".

This implies that
1) the first shot may go somewhere that isn't predicted by a larger dataset (I.e. group or groups overlaid) and
2) the first shot does go in the same place every time, or more so than groups would indicate.

I felt like testing this with my rifle system. Does the first shot from a cold bore tell me anything different to say, just banging out a 10 rd group ?

I've been taking the same target to the range every time I go shooting, and fire the first round of the day at it. Same shooter same rifle system, different conditions. Obviously breaking position quite significantly between shots.

I'm up to 7 days of this. So far, all 7 shots have fallen within a 24mm dot at 100m (about 0.8moa), .24MRAD.

The point of impact for all these shots so far falls within the footprint of a 10rd group fired all at once.

This isn't terribly surprising or enlightening. I'll continue shooting the same target each range trip, although it is in danger of falling apart, but I don't think there is a lot to learn from it with this rifle system.

It would be extremely interesting to see others do the same.


A 10rd group fired all at once - zeroed with 1 click left afterward.
Attachment 256323

7 rounds fired over 7 different range trips, 1 shot at a time - with the zero established with the 10rd group above.
Attachment 256324

All 17 of these shots would have been a dead deer. Fortunately I'm not experiencing a shortage of dead deer so I don't mind that they resulted in dead paper and increased knowledge instead.

Someone has done this before I'm pretty certain, still worth resurrecting

Interesting alright. I can give it a nudge too, I went to the range this arvo before I saw the thread, but I have my cold bore shot identified.

I did something unthinkable, I shot a 3 shot group just for my own pleasure and to see if the cold bore one was off - if at all, but not by much as it turned out, I think a 10 shot group would have dragged it in.

Another thing. Breaking position. If you're hunting your position is always going to vary a lot, down low on bipod to shoot over a ridge of rock, up high to get over a tussock, sitting, etc etc.

It would be interesting to test a rifle of "known accuracy" across several positions to see how much it altered. Very difficult to eliminate the shooter variable I guess. I did once read about a US shooting team guy in some sort of military style match shooting who had to make specific sight adjustments according to his position. I can't recall if it was due to the rifle ( a grarand I think) or other factors.

Agree with zeropak. Only just bought a chrony, cold clean shots at 7 deg lately show a significant lesser speed. Average speed 5 shots was 2594 first shot was 2566. Good thinking Gimp. Don't notice that at 100m but longer shots certainly.

A "cold" shooter (first shot of the day) probably has a reasonable effect also. Most practice/ grouping would be done prone, for the average hunter there would be very little positional shooting.

Originally Posted by zeropak

When you say cold bore. Is that bore clean or still fouled from previous sessions. Personally I have noticed that with all the rifles I regularly shoot (2 x .223 and 2 x 6.5CM) the first round through a cold, clean bore always has a slightly lower velocity than shots subsequently fired in the same session, around 30 fps. The POI at 100m doesn't seem to be affected but I guess the lower velocity would start to make a difference at longer ranges

I have data from dozens of groups and several different rifles and there's no trend for the first cold shot to have a velocity that is outside of the normal spread or that is higher or lower. That said this is from fouled cold bores mainly rather than scrubbed back to bare metal.

Originally Posted by zeropak

When you say cold bore. Is that bore clean or still fouled from previous sessions. Personally I have noticed that with all the rifles I regularly shoot (2 x .223 and 2 x 6.5CM) the first round through a cold, clean bore always has a slightly lower velocity than shots subsequently fired in the same session, around 30 fps. The POI at 100m doesn't seem to be affected but I guess the lower velocity would start to make a difference at longer ranges

Dito...... every time, from a Kimber Montana 260. first shot from a cold clean bore always has a lower velocity.

Interesting on the cold bore velocities, I just analyzed 8 strings across two rifles (a 22 CM and a 6mm CM) and only one of the 8 strings had the first shot at the lowest velocity for that string. Hard to be completely sure after the event but I'm pretty sure they were all commenced from a cold bore.

My mate since passed away, would shoot two rounds into the bank before he went hunting. He knew his rifle would group well after those two fowlers, my old 303 would start to wonder after a few shots so I would only shoot one shot at a target to zero it in. I’m lucky with the rifle I have now very lucky in that its first shot is on the money.
I’m very interested to test the multiple position one shot group as I’ve always wondered if a change alters my zero. I’ve never missed a dear but have not always hit them were I thought I aimed.