Range Report MOA decreasing out to different ranges. 6.5 PRC

[Bullspotter]

Seemed strange to me on working loads up in 6.5 PRC, 24 inch 1/8 twist barrel with 156 EOL and RL26. Found low velocity spreads with 2 powder charges. 56.6 to 57.0. so i chose 56.8 for my loads, no pressure all good. Shot many groups at 100. adjusted seat depth, several times, looking for the winner, No real change...... They all ran about .6 .7 groups.

Finally found some data on here that came from berger with the COAL being 2.950, so i loaded 5, took to range and shot 5 at 100. .68.......... F ME..... not happy at this point because i was getting .3 and .4 groups with nosler CC, but i dont want to hunt with those. So i decide to see what they were doing out further. Go home load 8 rounds, go back to range, 4 rounds at 200, and 4 at 300. No wind 4, shot group at 200 was .88 and the 300 yard group was 1.3......... Blew my mind as i was hoping for at least moa to open up the .68 from 100 to (.68x2) 1.36 at 200 and (.68x3) 2.04 inches at 300. The entire way home I was frustrated as im thinking their was no way in hell those were legitimate groups.

Loaded up 12 more rounds and went back the next morning, it was a little cooler 34 deg, shot 100, 200 and 300 with almost the same exact numbers. WOW, So i go home, load 20 rounds to get rifle zeroed, as i shoot off the the side and low for test groups so the aiming point dosent get trashed, adjust 100, 2 shots to get on zero, shoot 3 more in about a .6 group, send 1 down to 300, adjust, send one more and its spot on a 2 inch orange sticker, send 2 more at 300, last 3 at 300 were .9....... took gun home, cleaned the hell out of BBL, went back, shot 3 foulers at 100, 1st shot went 1 inch high and right, next 2 were .5 apart dead center. sent 3 at 300. and got a 1.1 group. So with 4 different shooting trips with the same results is my rifle really a .6- .7moa shooter at 100, .42 at 200 and a little better at 300? Last 5 rounds i shot at 25 with the MS V3. 2904, 2912, 2900 2920, 2906. Went home and loaded the last 20 bullets in the box for hunting.......

Sorry for the long post, but normally the little bit of long range work ive done the results would start with a little better moa at 100 like .4 .5 and get worse by a bit as i go out, maybe a tenth moa from 100-300. Be like .8 or so at 1000-1200.

Any of the more experienced LR shooters/loaders have any advise with this??

 

[clcustom1911]

I can totally feel your frustration. I was there when I was trying to wring out every bit of accuracy out of a bullet a year ago or so. My experience was not yours, nevertheless it made me pause and ponder like what you're doing here.. so, from my perspective:

First thing is **Based on your posting above, your rifle/ammo combo at sub-MOA accuracy across the board is plenty accurate for what you're saying you want to do with it**

That said, I don't pretend to know what the issue is. I'm just gonna throw a few thoughts out there.

-factory rifle? Custom?

-8 twist may not be optimum for the long 156's

-You're doing a lot of back and forth, making a couple rounds here and there with multiple sessions at the reloading bench... essentially testing multiple lots/batches of ammunition with the same recipe...

-"cleaning the heck out of" your barrel while in the middle of load testing may not be the best idea because that introduces another variable where it takes up to 10-15 rounds for things to settle down back to your sweet spot.

-are you hunting Quail or rabbit at 500 yards? Is all the extra effort worth the frustration? Will the animal youre hunting know the difference between getting smacked by a .6 moa weapon system at 100, or a .4 moa weapon system at 300?

 

[MOUNTIC]

I'll echo the above post.

My 6.5 prc with 156 bergers likes to be right at the lands. TS customs build and Its a "match" .120 freebore so that COAL at the Lands is 2.970 and still fits in my magazine. Barrel is a 7.5 twist. The rifle shoots 3 round groups in the .2s and 5 round groups in the .45 to .5 range almost every time. This is from a full custom hunting build. 55.3 gr of RL26 at 2900 fps out of a 22" tube with TBAC u7 can. Using ADG brass. If your using Hornady brass I would switch.

For me, my accuracy node was in the 54.5 to 55.5 range on two different 6.5prc guns (other is a 7 twist) with that 2850-2900 fps range and the 156s. If you have lower SD/ES where your at now, the .2 difference is not going to make your miss a deer or other target that the 156gr pills warrant.

Was the spread vertical or horizontal? Shooting off bags? Whats the routine? Did you let the rifle cool between groups? Are you able to shoot .4 or even.6 all the time, every time in other hunting guns? I know some of my bench guns probably can but in reality we are the weak link as shooters. I would take it hunting in a heartbeat if it was me. Hunting guns with thin profile barrels (if thats what yours is) sometimes don't like 5 round groups. I usually shoot 5 in all my target guns but the really skinny barrel hunter guns I am plenty good with 3 if those results are repeatable.

We will forever be chasing down accuracy and the reality of it is, a 1 moa gun even on a mule deer at 1000 yards is dead everytime. If you do your part, know the dope and the wind of course. A .6 inch gun your killing pigs still at 1000. Your deer, elk, bear won't know the difference if your half inch off center at 300 yards. Just take a piece of paper and make an inch line with two dots on the end. That is the difference between a .7 moa gun and a .4 gun. (Rough numbers) at 300. Then think about it for a second how that looks on an animal.

Have a good hunt. Your rifle is ready. Go have fun.

 

[Bullspotter]

Thanks for the reply's guys! The rifle is a Christensen Arms Traverse. Was shooting off a matrix support, off a concrete table with a rear bag. Strangely enough no wind at all.

I was shooting the final loads fairly slow, would say 30 secs apart, maybe longer in some cases, Barrel never did get hot, was slightly warm, did have a few times where it got cold running targets out ext. Public range with a lot of people some times, I would wait for shooters on ether side of me to shoot so i wouldn't jump when they shot and toss a flyer ext.

This was kinda the end to my load development. I had done the majority of load work ups before this, shot nosler 140CC and 143 ELDs also. lots of different charges of IMR7828, only ran the RL26 with the 156. All this shooting was at 100, I agree things would be better with a 1/7 or 1/7.5 twist. The nosler bullets shot the best groups at 100 by far. ELD did good and i think the 156 did good. Did not have the velocity i wanted with the 7828, I am truly not unhappy with the groups at 100 with the 156, knowing what they do at 300 for sure, I wanted to get all the accuracy out of it i could with what i had on had, And feel i did so, and the last several range visits made me gain a lot of trust in the load and the rifle, I feel all my groups are repeatable. Just seemed odd to me that the groups acted like they did when I moved out to 300, Wish i would have moved out to 300 sooner. Next time!! I also did not expect to shoot those small groups repeatedly at 300, I consider myself a fair shooter, but i have a lot of improvement areas im sure. One thing i think i have on my side was i was a very serious Archer for 30+ years, I apply some of the fundamentals to rifle. I know when i shank a shot with my rifle at 300, its a miss by 3-4 inches, a shanked arrow at 20 yards is 8 or 10! And one at 50 holy F!! LOL

 

[Ledzep]

They all ran about .6 .7 groups.

The rifle is a Christensen Arms

That's where I stopped reading.

Not dogging them, for the money, and for what they are they have a spot in the market, but I've never been impressed with their barrels from a pure accuracy standpoint. Weight vs. accuracy vs. still having muzzle threads, sure. But pure accuracy if you're sub-MOA for 5-shot groups you're doing good as far as I'm concerned.

That aside, the topic of group size (in MOA/mils) shrinking with range has never been proven to exist. The testing I've done personally and seen done by others says that it doesn't exist, and usually it's either a mental or optical issue (parallax, for example). I have seen groups that were shot at 500yd with a piece of paper at 200yd, and the 500yd groups look exactly like the 200yd groups, just with the holes scaled further apart. I've been able to do similar things at 100 and 200yd at the same time (100yd paper, 200yd acoustic target, groups and shot placements look identical, just scaled). In short, once a bullet is on a given path, it remains on that path unless acted upon by an outside force. You'd have to rely on downrange thermals/wind to correct your poor 100yd groups at further distance and mother nature is not here to help, most of the time

 

[chutinlead]

I am running the same bullet in my 6.5-06 running 2815fps and at 100yds it shot .8 groups when I was getting .3-.4 with ELD-Ms. I backed off to 170 yards (most I can get off my back deck) and I shot a .5” group at 170yds. Confused, but more than ok for hunting deer out here in WY.

I'm not entirely sure the 1-8" twist is fast enough for these 156gr long bergers. Or something was better about my setup at the further distance.

 

[Bullspotter]

I am running the same bullet in my 6.5-06 running 2815fps and at 100yds it shot .8 groups when I was getting .3-.4 with ELD-Ms. I backed off to 170 yards (most I can get off my back deck) and my group shrank to .5 at 170yds. Confused, but more than ok for hunting deer out here in WY.

I'm not entirely sure the 1-8" twist is fast enough for these 156gr long bergers.

Have you shot any game with the 156? How did it do?

 

[chutinlead]

Have you shot any game with the 156? How did it do?

Yeah I killed a mule deer doe opening day. Left about a 2" hole out the rib cage after a double lung hit.

 

[NCLR224]

I’ve been working with that same bullet in the PRC for a little while now with h1000. Been able to make it hit 2165y consistently, once wind was dialed in. It is an accurate bullet. Only thing I can say is that with the speeds it’s being launched at, 2900ish, it probably hasn’t ”settled down” at 100y. That long ass bullet needs a moment to stabilize in the atmosphere. A half inch difference to anyone other than a bench rest shooter at 100y is a “no factor” scenario to me. Plates are ringing and deer is down. I’ve come to expect an increase in moa with the longer boattails. You can probably find a flat base bullet that will give you a better 100y group and still work well out to 400y. Of course I don’t have any science to back this up! Always thought shooting was more of an art form anyway.

 

[chutinlead]

I was almost at the point of doubting the 156gr as a hunting round. Like it did ok, but all my kills have run 50-100yds and I am just not seeing the wham/bam/flop factor I would like to see.

Yesterday was opening day for a different deer area here in Wyoming and I tagged a doe to fill the freezer. Thought I hit her a little far forward as she was quartering away. Maybe I did. But the devastation and blood trail was intense. Erased all doubts I had about using it. Sure she somehow walked 20yds 3 legged with a 6” hole in the front of her chest, but was sure easy to follow.

 

[1moaoff]

I’ve been working with that same bullet in the PRC for a little while now with h1000. Been able to make it hit 2165y consistently, once wind was dialed in. It is an accurate bullet. Only thing I can say is that with the speeds it’s being launched at, 2900ish, it probably hasn’t ”settled down” at 100y. That long ass bullet needs a moment to stabilize in the atmosphere. A half inch difference to anyone other than a bench rest shooter at 100y is a “no factor” scenario to me. Plates are ringing and deer is down. I’ve come to expect an increase in moa with the longer boattails. You can probably find a flat base bullet that will give you a better 100y group and still work well out to 400y. Of course I don’t have any science to back this up! Always thought shooting was more of an art form anyway.

Bullets do not get more accurate at range.
This has been covered before.

 

[Commander Shepard]

Bullets do not get more accurate at range.
This has been covered before.

You’re spot on, and unfortunately this bit of folklore just doesn’t seem to go away.

Just to reiterate, bullets are not guided projectiles and they can’t correct back to POA. They disperse in random directions. If you’re getting 1MOA at 100yds, then the best possible accuracy you can expect at any greater range is still 1MOA. They can’t self correct to less than 1MOA, that’s the angular size of their randomly generated dispersion pattern.

Sorry to beat a dead horse, carry on.

 

[GrumpyOleFart]

Squeeze trigger hard, bullet goes further.

 

[Secant]

 

[GrumpyOleFart]

Jedi Bullets.