6.5X284 grouping question

[Rugerdiggs]

Here is the group i shot at 309 yards.

The gun is a trued and blued remington 700 long action with a 26" rock creek stainless barrel that is heavy taper with .820 OD at muzzle, setting in a bobby hart laminate stock with a 1 piece 0moa rail, SWFA tactical rings, and a Vortex Viper 6.5-20X44 mildot scope. The ammo is lapua brass, 49.0 grains of H4350, CCI BR2 primers, and 140Berger VLD hunting bullets .010 off the lands. The stock is not bedded or pillared and thinking that could be the reason its going from side to side. Had a 6-8mph tail winds but was pretty consistent and was nearly straight behind me and going to target. The group measured 1.883 and im happy with it but would like to get to 1.5 or better. Would love to get to 1". Am i asking to much from what i have? Please let me know your thoughts on how i can improve this, thanks in advance.

 

[Michael Eichele]

For 6 shots, thats not bad at all. Have you tried different powder charge weights? If not, try 0.3 down, then 0.6 etc....Also try seating depths. If you are .010" off the lands try .000-.005 into. Then try .040 out. Try another primer as well.

START WITH ONE at a time. with accuracy that close to where you wish to be, I would try seating depth 1st, then .3 grain down. If your extreme velocity spreads are =< 15 FPS, I would leave those alone.

 

[Rhino55]

Dude
You are shooting a sub-MOA group at 300yds! That is very exceptable! I built the same rifle for antepole hunting this year. I'm loading 49gr of 4831SC and getting 1/4 MOA group at 200 yds with 140gr berger bullets, Federal 215 primers. I Used a Keriger 1-8 twist barrel. Blue printed Remington action with a Greybull stock. It had a alumin bedding block in it. I would like to throat the chamber so I can seat the bullets out a little futher.
Beast of Luck
Rhino55gun)

 

[trebark]

As Michael prescribed, start with seating depth. Here's a great article about seating depth and VLDs....

http://www.longrangehunting.com/for...accuracy-berger-vld-bullets-your-rifle-40204/

Michael's other suggestions are spot on as well, especially the part about make ONE CHANGE at a time. That way you can measure the effect of the change.

 

[Greyfox]

Your group is very promising. The horizontal dispersion could be induced by wind effects. If you haven't already, I would test a few more groups to confirm before changing variables. I would probably bed the stock, but it may not be a factor in your group size. Have you chronographed your load?. You haven't mentioned any hunting requirements, but for 1000 yard medium game, velocities with extreme spreads give excellent results at +2950fps, <15fps, ES. Barrels are different, but both of my 6.5x284's gave best results, .25-.5 MOA at 500 yards, with Berger Hunting VLD's when seated further out of the lands, .075". Pressures tend to be lower as well when using max loads. I have found best results with H4831sc and Retumbo, the latter which produces 50-75fps higher velocities and tightest ES using Fed215 primers. I don't think you are asking too much from your rifle. the 6.5x284 is capable of very high precision.

 

[Rugerdiggs]

I have ran in .5 increments from 48.0-50.5 but 49 and 49.5 showed the best results in the .3' at 129 yards. I did chronograph my 6 shots and was all overt the place, i dont have a second chrony to check it by but its a brand new shooting chrony. I will try some seated back some and check results. I may have to try some retumbo as well. I would like to get to 1000yards on a whitetail and coyotes with the rifle. How many rounds do you guys think i should load and try with each change like the deeper seating depth and so on? I do have another question, on my brass its all been brand new lapua brass and i didnt trim it before first load was going to trim it all after first resize, should that effect much if any? Thanks

 

[Varmint Hunter]

I have ran in .5 increments from 48.0-50.5 but 49 and 49.5 showed the best results in the .3' at 129 yards. I did chronograph my 6 shots and was all overt the place, i dont have a second chrony to check it by but its a brand new shooting chrony. I will try some seated back some and check results. I may have to try some retumbo as well. I would like to get to 1000yards on a whitetail and coyotes with the rifle. How many rounds do you guys think i should load and try with each change like the deeper seating depth and so on? I do have another question, on my brass its all been brand new lapua brass and i didnt trim it before first load was going to trim it all after first resize, should that effect much if any? Thanks

When working up loads I typically load 3 rounds with each change. If a 3 round group doesn't look good why waste barrel life on 5 or more of each change? If a 3 round group looks promising then I'd try to repeat the performance or retest at longer range.

The untrimmed length of new Lapua brass should not cause any inconsistencies, IMO anyway. I rarely trim brass (for uniformity) until after the first firing. New brass is normally at the minimum length and really doesn't leave much room for trimming unless you're happy with "shortened" necks.

 

[Greyfox]

If you can figure out your velocity, and you are happy with it, I would work on your current load. Your short and long range groups are looking pretty good, and tuning up the seating depth, and working with fire formed brass may put you in the sweet spot. Getting a handle on velocity and determining ES should be a priority at this point.

 

[Rugerdiggs]

I will load up a few more at different seating depth with same charge and chrony them again to see if its close to what i measured, dont have my notes in front of me but think my es was more than 40, but going to try to get my father-in-laws chrony and put it in line with mine to have 2 sets of eyes on it and see what we get. Will the seating depth effect velocity much if any if you not into the lands on either?

Thanks for the help guys.

 

[Augustus]

Tail winds can and do turn into fishtails, shifts from 5 o'clock to 7 o'clock are difficult to detect. Catch a calm day before you start screwing with your system. An 8 mph wind fishtailing from 5 to 7 will yield about 3.5 inches of dispersion on the 6.5-284 at 300 yds.

 

[Rhino55]

One other thing I haven seen talked about yet is weighing your brass. Any loading for my 308 Palma rifle. I weigh my brass into +or- 2 gr groups. I have found with brass that weighs the same gives you a tighter group.
Rhino55gun)

 

[Rugerdiggs]

I will weigh the brass and get 3 of the same weight and load them and see if it helps, didnt know the tail wind would do that, thought it wouldnt change it much at all thanks alot.

 

[Augustus]

If the wind is a perfect 6 o'clock wind it will have no measurable effect at 300. The problem is the nature of wind, it's velocity and direction is usually variable to some extent. Fishtails will screw you over and are very hard to detect, trust me on this one, your groups are pretty good for the conditions you described.

Also you were worried your ES might be causing vertical dispersion. You think your ES is around 40 fps, this will cause about one third of one inch vertical dispersion with your set-up at 300 yds.

 

[Rugerdiggs]

What is an accepted ES on velocity if your going to shoot at 1000-1200 yards, would love to get it to single digits but not sure where i should be happy at.