Groups opening up at longer range

[Dusty]

Used the ocw method to come up with a load for my .308. Ended up using 45 gr. varget with a 175 smk, win. Brass, and CCI BR primers. Shoots .25 Moa at 100 yds. Went to the range today to try it out at distance, and results weren't that great. Groups opened up to 1 Moa at 600. Worse at 700yds. Chronoed them and the ES was around 40 something. Averaged 2660. Any suggestions on tightening the vertical spread up? I also had some loaded up with fed gmm primers, it didn't do any better.

I had another load I used that was shooting .25 Moa at 100. 155 Scenar, 45.8 8208, lapua virgin brass, and CCI BR primers. 3005fps, and it shot .5 Moa, but in the 100 degree heat I started getting ejector marks and a little friction lifting the bolt.

 

[Dusty]

Re: Groups opening up at longer range

Btw, these are being shot out of a bartlein .299 bore barrel at 26" length.

 

[wnroscoe]

Re: Groups opening up at longer range

41 to 42.5 grains of H4895, Lapua Brass, CCIBR2 primers, 175 SMK's. Should be 2,600 to 2,650 fps.

Run a ladder with your 155's and Varget, Lapua, CCIBR2. Back your 8208 load off by .3/.5 and re-try.

Proof test at 300 early in the AM, right at dawn if possible.

 

[JGorski]

Re: Groups opening up at longer range

Im shooting 42grs RE15 under 168AMAXs(Lapua brass) that has shot a 1.3/16" group @300yds, that same load went 9.3" @600yds, will be trying a different load with CFE223 instead which will give it a bit more velocity, we'll see if that helps.

 

[ShtrRdy]

Re: Groups opening up at longer range

Does your scope have enough magnafication and clarity to make sure you're aiming as small as you can? Are you adjusting out any parallax error?

 

[leadbullet]

Re: Groups opening up at longer range

I use the exact same load as you in a krieger 1-12 twist 25 inch and a TRG22, after a year of Fclass matches i can now shoot a hair over 1/2 MOA at all distances if there is no wind.
It could be your shooting technique and not the ammo, I found that out after having a couple high masters shooting my set up and found out it was me not the gear.
hope this helps.

 

[Dusty]

Re: Groups opening up at longer range

I normally have an old m3 mkIV 3.5-10, but I swapped out a 6.5x20 AO vx3 to use for load development. I dialed back down to 100 to make sure everything was still tight. Got one hole groups still. I had played with seating depth with this load and at 100 2.845 oal was the magic no. While doing the OWC load development, I had one hole groups from 45 to 45.4 that where all in the same poi. 45.5 started to spread.

 

[2clicks]

Re: Groups opening up at longer range

I say try a ladder test at 600 tune the load and roll with it.

 

[Wolfish365]

Re: Groups opening up at longer range

Yeah, I agree that it might be either shooting fundamentals or your load. There's been a great many shooters discovered that loads shooting excellent at 100yds (the standard to tell if your equipment is accurate) are sometimes not so great at 200yds or beyond. So do some load adjustment and keep up with the shooting fundamentals and you'll get what you're after.

 

[rcamuglia]

Re: Groups opening up at longer range

+1 with the guys recommending abandoning 100 yard load development.

I've had many loads that shoot one hole groups at 100 yards but at long range perform poorly. I now only develop at the longest range possible. At 600 with the targets I've devised, I can see the bullet impacts through my scope. This saves a bunch of time driving down to the target to check it out. If you have a buddy and an F Class range with pits, shoot the test at an even longer range. Shoot long range groups and find a load that has no vertical stringing. This, by definition, is the load that has the most consistent velocity and is exiting the barrel at the proper time.

Once you have the load and dope, all you will have to worry about is becoming a wind reading Guru...

 

[JoshcBoucher]

Re: Groups opening up at longer range

I'll voice an opinion, on the "scope idea". I moved up to 32 power, on everything, and it helped close the groups, alot!<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ShtrRdy</div><div class="ubbcode-body">Does your scope have enough magnafication and clarity to make sure you're aiming as small as you can? Are you adjusting out any parallax error? </div></div>

 

[TexIndian]

Re: Groups opening up at longer range

How serious is your brass prep? I had a similar problem years ago when I was getting started. Loads that shot ragged holes at 100 started coming completely apart as I moved out to longer ranges. Little by little I started improving my brass prep (I was doing almost none at first) and my longer range groups started steadily improving. I can't point to one thing that made all the difference, but collectively the same gun/scope combos that shot bad at distance now shoot great with only minor changes in the basic load.

Of course, the fact that your 155s are shooting great may point to problems other than brass prep. What were your SDs with the two loads?

 

[Dusty]

Re: Groups opening up at longer range

The 155's where using virgin lapua, and single digit sd. The 175 load was using 3x fired win. As far as case prep, I annealed after the 3rd firing. Flash hole deburred and trimmed to 2.005. ES and SD where high on this load. I loaded up some 175's in the lapua brass, and had single digit SD.

 

[MALLARD]

Re: Groups opening up at longer range

your complaining about 1 moa at 600y ? most guys will shoot 20 shot 20inch groups at 1000y , and that is considered pretty normal. Guys who win 1000y matchs shoot around 20 shot 15in groups...

so dont beat yourself up. Using a 308 to do 1000y shooting is also an uphill battle. Most guys who do well at that distance shoot 6.5's. The guys who do shoot 308's and win have some serious equipment and the experince using it.

if your not sorting bullets by weight and ogive, and pointing and meplat trimming, now is a good excuse to begin.

and stick with lapua brass

 

[ChadTRG42]

Re: Groups opening up at longer range

If you want a long range load, test it at long range. I test my initial loads at 300 yards. At this distance, you can see what the true accuracy is. If you have a calm day, try it at 400 to 600 yards, and use that load. Often times the best 100 yard load is not the best long range load.

 

[Deadshot2]

Re: Groups opening up at longer range

Being a member of the "Card Carrying Old Farts", I'd say that the scope can be a source of larger groups the farther you go.

Parallax is a big issue with many scopes. What's a small error at 100 yards is 10 times bigger at 1,000.

It's also 10 times more important that your rifle remains steady throughout the firing process to keep the groups smaller at distance. From the moment your brain says "fire" to the moment the bullet leaves the muzzle, time passes and the rifle can move from the point of aim a minuscule amount, all adding up.

 

[Unknown]

Re: Groups opening up at longer range

Parallax, wind, or your eye position in relationship to the ocular lens can make a big difference in group size.

Even a tiny shadow around the edge of the ocular lens throws your bullet out to the opposite side of the scope.

Another thing I found was that Leupold scopes without a lens filter don't resolve red/orange spectrum as well as they do the blue/green. When I switched from red/orange targets to targets of another color spectrum my groups instantly got smaller. It was because I couldn't resolve the edges of the red/orange targets very well with the Leupold scope. My guess is that it is a function of the coatings on the lenses.

But, when you think about it, it would make more sense for Leupold to want the blue/green spectrum to resolve better, because there is alot more of that in nature than there is of the red/orange.

 

[Dusty]

Re: Groups opening up at longer range

My 155 lapua load holds .5 Moa at 600 with me shooting it. It's just the 175 SMK load that is opening up and having wide ES. So I don't think it is the scope or my technique. I could be wrong, but I have shot these loads back and forth and get the same results each time.