I think I know the answer but......

[rjm158]

Last week I bought a new Tikka T3x in 270 Win. I outfitted it with a scope and along with two handloads headed to the range to sight it in. I had loaded 130 gr SST's and BT's over the same charge of RL-16.

After getting the scope adjusted, I proceeded to shoot groups at 100 yards. These were 3 shot groups and I cooled the barrel between groups using a Chamber Chiller device (wonderful item, BTW).

With each group, regardless of bullet used, I had two holes touching or nearly so and one 3/4 of an inch away or so. The location of the flyer varied slightly but the distance was virtually identical.

My theory is that the flyer was the first shot fired from the "cold" barrel and the other two were from the "warm" barrel. Being the ballistic genius I am, it never occurred to me at the time to slow down and check each shot through the spotting scope to verify this.

So, do you guys think I'm correct or is the potential cause something else?

Ron

 

[FOTIS]

try 4 shots. I always make four. Three for group, one for verifier if needed.

 

[DrMike]

try 4 shots. I always make four. Three for group, one for verifier if needed.

This.

 

[JD338]

Or use the chamber chiller between shots.

JD338

 

[walkinhorseman]

One or two 3 shot groups is not a statistical credible sampling. Perhaps the three shot groups are the true precision for this load.
What type of wind flags are you using?
If you prefer 3 shot groups, shoot five groups with each load and take the average. An average of ten groups would be a better sampling.
Go back on a different day and reshoot the loads. Never make final sight adjustments or load decisions based on one shooting session.

 

[walkinhorseman]

One or two 3 shot groups is not a statistical credible sampling. Perhaps the three shot groups are the true precision for this load.
What type of wind flags are you using?
If you prefer 3 shot groups, shoot five groups with each load and take the average. An average of ten groups would be a better sampling.
Go back on a different day and reshoot the loads. Never make final sight adjustments or load decisions based on one shooting session.

 

[walkinhorseman]

Sorry for the duplicate. Tried to delete one but couldn't find the button?????

 

[SJB358]

Ron, if it repeats like that over a few 3 shot groups usually shortening the COAL a few thousands will pull it in. I don’t really let my barrel cool between shots since I wanna see where 3 rounds land in a warm barrel. Since the 3rd is only about 3/4’s out I think you could minimize it with seating a little deeper. Still, sounds like a typical Tikka and is just laying them in there.