Large group size

[Joefrazell]

Okay, so the past few years I've been doing larger sample sizes for finding true rifle potential. Yesterday I shot a 17 shot group of 200 grain hybrids with my 20" suppressed 300 prc. I almost stopped shooting after the first 5 shot group but denied my negative thoughts and kept shooting. This is a great example of why shot sample size is important. Note: I'd normally do 20 shots but ran out of bullets. This is also a random load of retumbo and seated to the neck/shoulder junction and probably has 150-250k jump.

First pic is first 5. 2nd pic is after 10 rounds. Third pic is after 14 and then final pic is 17.

The 17 shot group size is right around 1.5". 14 of the shots went into .75". The first 5 shots was around 1.2"

 

[RichCoyle]

It looks like you didn't get much new information after the first five or so.

 

[Joefrazell]

It looks like you didn't get much new information after the first five or so.

That's kinda the point though. That first group could have easily been the last group and I'd of thought I had a load that I didn't. I also think it's good to point out that out of these 17 shots there were 4 groups of 3 shots that were under half minute. Also, if I'd of stopped shooting I wouldn't consider this load. Truth is 17 shots for 1.5 min. Is actually pretty good.

 

[Wolf76]

Makes me think your gun likes a dirty barrel.

 

[Joefrazell]

Makes me think your gun likes a dirty barrel.

That's a good point. The barrel had been sitting for about 8 months uncleaned and I just spun it back on for this group.

 

[slick Nick]

My 300WM is like that likes to be a little dirty.

 

[Joefrazell]

the barrel did have a bit of corrosion inside. Before the groups. Notice the first two shots that are about 3" higher than the group? Those were the first two shots out with a different load that's known to shoot out of this barrel. But maybe it took a few more to get things back in a homeostatic point inside the barrel.

 

[nksmfamjp]

It looks like you didn't get much new information after the first five or so.

We'll, the first 5 tells me that 5 shots go into about 1.2". The others tell me that 17 go into about 1.4". I didn't try to calculate a mean radius or my preferred mean diameter.

To me, mean diameter + 2 std deviations tells me what the target size I can hit is pretty important.

If I shoot 3, 5, etc shots, what does that tell me. I like my Sd's off a 3 shot group the best, but cannot use them for much!


BTW, OP, that is a decent load. Wonder if something might get the few flyers reel'd in??

 

[Stevenstl86]

Quite a bit of a jump but I know there isn't much of a choice. What was the velocity?

 

[dfanonymous]

I always ask this since human error is more prevalent. We now this because of competition or anytime we shoot with someone in person.

How much of this is the shooter?

The second thing is ES never gets better, right? If ES is a function of SD, (i'm talking group size, not necessarily velocity) then it's safe to assume that, yeah, the more you shoot, the more of a dialed in estimation of the gun…and shooter, accuracy combo is.

how long did you let the barrel rest between shots, and what barrel profile?