First 600 Yard Group, Any Input?

[cowboyarcher]

Hi Guys,

I was able to get out this morning and put my first group up at 600 yards, ever. Prior to this I had been able to shoot only to 400 yards on paper.

Anyhow, here is the info on what I was shooting:

Semi-Custom Model 70 in 270 Win, 24" McGowan Tube in a B&C ultralight medalist stock. I've shot just over .5MOA at 260 and 400 yards with this fairly consistently off a bi-pod.

I am running 57gr of H4831SC under a 140gr Accubond, and am guessing based on drops to be getting 3020FPS with them.

Scope is a Nikon Monarch 4-16x42SF in Talley rings/bases. I used Nikon's Spot On program to calculate the dope seen on the target. I have it zeroed at 270 yards, and dialed up 32 clicks and right 9.

Environmental inputs: 7200', 75% humidity, 55 degrees, 30.19 in. pressure, Wind 5-15 from the SE.

As this is my first group at this distance, just looking for any input or suggestions get my groups down in size.

Thanks for any help fellas, and that sure was fun! I think I will be getting out to shoot this far and more, more and more!

Adam

 

[BMF]

If your shooting .5 MOA at 260 and 400 yds then your load sounds somewaht solid. It looks like about a 9in group at 600 so there's something happening here. It might be a form issue. Make sure that you put the same amount of shoulder pressure into your rifle every time. Especially if its a lighter gun. Be consistent here, it makes a big difference.
It also may be a velocity issue. Without a chronograph it'll be tough to tell. Actually the more i think about it, it's probably a velocity issue. Past 400 yds is where you start to see loads with a high ES (estimated spread) begin to string shots vertically. First, make sure that your powder scales is consistent and repeatable.
You can also play with seating depth a litlle. Maybe try seating 4 loads, ten thousandth deeper into the case. I dont want to say the other way (into the chamber) because i dont know where your at now. It also looks like you got some wiggle room + or - with your powder charge. Sometimes .3 or .5 more or less grains can lower the ES.
I don't know what primer your using but it should be a quality one. You can do a search on this forum to decide for yourself which ones are the best. But CCI, Federal, and Winchester seem to be used a lot. Then if you go to the CCI and Federals Benchrest and Match primers, they're even better
You can do this without a chronograph, its just a little tougher. But if you plan on doing a lot of long range shooting, it might be worth investing in one.
There's a thousand different things to consider when reloading that can shrink group sizes, its mind boggling.....best thing you can do is get on this forum and read, read, read, and become a sponge. Lots of knowledgeable people here.

 

[farout]

Do you shoot free recoil? If the muzzle rises at all during the shot, you might want to try changing your hold and see what happens. Try holding onto the stock just forward where the balance of the rifle is. This will probably be somewhere just back of the front of the scope. No need for a death grip. Just be consistent and enough to keep the barrel from jumping. The two shots at the bottom of the group are about 4 inches. That is sub-MOA! The other shot is high left and is the one that blew out the group. That is why, I think, it is muzzle jump.

Good luck and let us see that next group. gun)

 

[cowboyarcher]

I did end up resetting between shots 2 and 3 as something shifted under recoil and my level was off. I am shooting from a non-swivel bipod, so I think getting one with a swivel head might help. This might explain a difference in shoulder pressure?

It is a light rifle btw - comes in at 9.5 lbs scoped and unloaded, including the bipod.

As for the hold I use, I have the right hand loosely on the grip, just enough to work the trigger, and the left is on a rear sandbag. I get a fair amount of movement between shots, even with the break. . .

 

[roninflag]

3 shots do not tell me enough.

 

[mikeg1005]

Do you have a level bubble of your scope? When I added one to my rifle my long distances groups basically shrank in 1/2... I was canting the rifle slightly with every shot I took.

 

[aramarine6]

Was that high shot your first or last of the three? If it was your last shot then I'm putting my money on a velocity issue. If that round was sitting in a hot chamber for more than 10 seconds, then that will cause a higher velocity. Not a huge jump but at distance the change will be noticable. I also disagree with the idea of holding the stock forward of the balancing point. You want the rifle to recoil naturally. The more you attempt to fight the effects of recoil by putting added pressures on the rifle using your body, will cause you to have alot of flyers. Bipod and a rear bag should be all you need. I agree with the level on your scope statement. Also shoot 3 seperate 5 round groups. It'll be much easier to figure out what the issue is then.

 

[cowboyarcher]

Watched a few videos on prone shooting and saw a few things I was doing wrong:

- I had no bi-pod load, causing some odd torque during recoiling I'm sure.
- I am putting some funky torque on the stock by muscling it to get my point of aim rather than doing it in the rear bag.
- I'm also not centered behind the rifle and thus am not seeing edge to edge clarity in the scope.

Looks like I need to get out a smaller rifle for a while and do some form work. I've never had training on a LR rifle, but have in other shooting disciplines (competitive archery), so just need some trigger time, and maybe a video camera to record myself. Of course if anyone is in SE WY, I'd welcome some instruction!

 

[walkinhorseman]

3 shots do not tell me enough.

+1 to that.

You can't put any creedance in one 3 shot group. Particularly if this is the first time that you've shot this distance. I strongly recommend that you shoot 10 shot groups on several different days under different conditions before you jump to any conclusions. Get yourself a 600 yard F-Class target to shoot on and keep records. You currently have no statistical basis to be making decisions on.