Defensive Carry banner

1 - 9 of 9 Posts

Super Moderator
Joined
13,011 Posts
Discussion Starter #1
Sometimes, I guess, it's just not that simple :confused:

I devised a simple test to see what the best charge for my 16" AR was. I knew I would be using H4895, Hornady 75 gr BTHPm bullets and Winchester cases.

The plan was to fire 20 rounds of each test charge and shoot the 20 rounds as four, five shot groups. I could have shot them as a single 20 shot group, but I have reason not to use that approach which I won't get into here, but if you want to know, I'd be glad to add it.

The charge increment would be 0.1 gr starting at 22.9 gr and continuing through 23.6 gr. After completing the shooting, it should be a simple matter to pick out the charge that produced the best accuracy.

I chose 20 rounds because it gives far more reliable, dependable results than 3-5 rounds.

When I finished the shooting, the winner is not at all obvious!

So here's where you come in. Take a look at the 8 targets and pick two charges you see as giving the best accuracy.

A couple of targets require explanation. One, the suppressor on the 2nd group of the 22.9 chg so we have to ignore that one. Then for the 23.5 chg I just had to shoot at 5 pennies instead of a dot. I missed everyone of them 馃槚 and it cost me a group on top of that. But I carefully measured the hits from the center of the pennies and transferred the hits on the last four to the first penny to form an adequately accurate group.

I measured the 5 shot group and the best 4 shot group. That might help with a really good group with an outlier. So the number on top is the 5 shot group and the number on the bottom is the best 4 shot group.

So here are the pics of the 8 targets - which charge do you see as the best charge for accuracy?

And thanks much!

22.9 gr


23.0 gr


23.1 gr


23.2 gr


23.3 gr


23.4 gr


23.5 gr


23.6 gr
 

Premium Member
Joined
672 Posts
Wow! I do admire your tenacity in pursuing an answer, Tangle. For me, I would pick the 23 grain target. It seems to be the most consistent to me with the closest grouping overall. That's some good shooting, too, by the way!
 

Premium Member
Joined
237 Posts
23.3 and lower shows some really good groups. Which direction were you shooting the targets? Left to right? I can see tighter groups in the lower right circles.
 

Super Moderator
Joined
13,011 Posts
Discussion Starter #4
23.3 and lower shows some really good groups. Which direction were you shooting the targets? Left to right? I can see tighter groups in the lower right circles.
Thanks, yes order is upper left to right, then lower left to right.
 

Registered
Joined
508 Posts
I'm going to have to agree with NavCop. The 23.0gr groups look the best. Although I'm not sure what was going on with the 23.6gr groups. Were you getting tired, or not settling in? Anticipating the shot? Those start out looking really good, but there's a flier in every group that spoils it. I'd be interested in seeing those two for a side by side comparison, on a fresh day.
 

Super Moderator
Joined
13,011 Posts
Discussion Starter #6
I'm going to have to agree with NavCop. The 23.0gr groups look the best. Although I'm not sure what was going on with the 23.6gr groups. Were you getting tired, or not settling in? Anticipating the shot? Those start out looking really good, but there's a flier in every group that spoils it. I'd be interested in seeing those two for a side by side comparison, on a fresh day.
That's a good idea to try them side by side!

I'm not sure what happened on that last 23.6 gr group. It could have been me losing focus on the last group.

As for the outliers, I noticed that too. Honestly, I think the outliers may be as representative of the group accuracy as the tight shots. I mean if I shot say 5 more shots at one dot, I would not be surprised to see other shots landing away from the tighter shots.

It's a good idea about reshooting the two top groups; I'll do that Monday. I'd do it today or tomorrow but I'm giving my shoulder some extra "off time" to recover from shooting that light weight .308.
 

Premium Member
Joined
237 Posts
Thanks, yes order is upper left to right, then lower left to right.
OK, that's what it looked like. If shooting left to right, the first groups would be slightly loose due to a cold/cool barrel and then tighten up when it got warm. Shoot some burner rounds to warm the barrel up and then shoot the first 4 loads back to back, then see what the groups look like. IMO, still think the 23.3 and lower loads are going to be your best bet.
 

Super Moderator
Joined
13,011 Posts
Discussion Starter #8
Well, I used the charge @NavCop; suggested, supported by @kenboyles72; and I did what kenboyles72 suggested, use warm-up shots before the first group.

This is the results - 5 shot group size on top / best 4 shot group under it.



Notice the first two groups (upper left and upper right) were quite tight! After those two, I sensed a let down, believing that those two adequately represented the load and gun. I had all but decided to stop there and go to 300 yards, but I thought it better to finish the test.

I did pretty good on the 3rd set and the fourth set is actually better than it looks. Between the 3rd and 4th groups there was a long talk pause. A young man at the other end of the range was having scope issues and my PRS buddy and I walked down to see if we could answer his questions. By the time I got back to shooting, my rifle had cooled to the cold bore point.

That high shot in the 4th group is the cold bore shot - and possibly a bit of me.

So I"m pretty happy with this load - that'll be my goto load for this gun setup.

Thanks guys for the help analyzing the targets and suggestions! (y)
 

Premium Member
Joined
672 Posts
I'm glad things worked out for you, Tangle. There are some TIGHT groups in there!
 
1 - 9 of 9 Posts
Top