accuracy in load developement

[trueblue]

At what point do you call it good for long range accuracy in load developement? I don't want to burn a barrel out in the process.
Doing load developement for my 300 JAZZ and am at .5 MOA groups at 500 yards, and .7 MOA groups at 725 yards. Have not gone farther in distance yet.
I plan on verifying this performance a few more times, but at this point I am thinking of just verifying my cold bore shots and trajectory and call it good.
I guess my question boils down to what is good group size at 500-1000 yards
Most of my spread seems to be verticle.

 

[winmagman]

Before I call it good I have to know I can hit my intended target at the ranges I will be shooting. Obviously it takes a much more accurate load to hit a coyote with a 6" kill zone at say 800 yds than it does to an elk with a 18" kill zone.

I'd be happy shooting at anything with your load at 750 yds.

Chris

 

[britz]

I usually play with load development somewhat constantly. Every year I pick a load to hunt with and sight in with that and create a drop chart... but I usually get bored or read about a better bullet combination, or do some fiddling with load development to try to get more consistancy. I have a tikka 300wsm I bought in 2007 and have around 600-700 rounds down the tube now. I also have a 22-250 I bought last summer and have about 700 rounds down it too with out one varmint hunt involved lol! I like to fiddle with load development to the point of it getting frustrating.

 

[Joel Russo]

How much Jim?

 

[trueblue]

Joel,
My verticle is about 4.5-5" at 725 yards, and the horizontal about 3". It could be my shooting technic on handling recoil, or something in my reloading. Brass is annealed after every firing, full length resized, trimmed, uniform pockets, deburr flashholes, necks turned only to clean up thickness. I use a RCBS Chargemaster 1500 and double checked charge weight on a balance beam . Last night conditions were good for shooting, with know mirage, and a 2 mph wind. I did notice a slight difference in neck tension on a couple of rounds when seating the bullets, even with the necks turned to 0.0145 thickness. I was surprised by this, as I would have thought with the necks all the same thickness the seating of the bullet pressure would be the same.

 

[Mikecr]

Why do you reference your 'grouping' as if your long range 'accuracy'?
Is this benchrest or hunting?

If it's for hunting then I suspect you haven't actually begun load development.

 

[esshup]

trueblue:

What's the velocity spread in your group?

 

[trueblue]

esshup - velocity spread is 25fps.

Mikecr- I don't understand your point. Please elaborate. This is my hunting rifle.

 

[nddodd]

Joel,
My verticle is about 4.5-5" at 725 yards, and the horizontal about 3". It could be my shooting technic on handling recoil, or something in my reloading. Brass is annealed after every firing, full length resized, trimmed, uniform pockets, deburr flashholes, necks turned only to clean up thickness. I use a RCBS Chargemaster 1500 and double checked charge weight on a balance beam . Last night conditions were good for shooting, with know mirage, and a 2 mph wind. I did notice a slight difference in neck tension on a couple of rounds when seating the bullets, even with the necks turned to 0.0145 thickness. I was surprised by this, as I would have thought with the necks all the same thickness the seating of the bullet pressure would be the same.

I apologize for using your thread to ask a question but how much difference does it make in the neck tension of your bullet.

Thanks
Nathan

 

[Mikecr]

When you say your grouping is .5moa at 500, how is it correlating to accuracy?
I'm not trying to be a smartarse or anything. It sounds like your serious and I'd like to help.

Do you mean that your hunting system at this point is capable of single cold barrel shots impacting ~+/-1.25" from mark at 500yds? Or do flyers take them 2.5" furthest from mark?

I wonder because a .5moa group beginning 3" from your aiming point is not .5moa of accuracy.

 

[kiwi3006]

Mikecr has a good point. There is no point shooting a really small group if it is way off your aiming point.

How many times do you expect to shoot the animal you are aiming at? I would imagine it is only once.

Your accuracy range should be the range that you can consistently put your first round into your selected kill zone. Might be something like 8" wide by 12" high. You might make this bigger or smaller depending on what you are hunting.
Your 0.7 MOA at 725 should put every round into this kill area, but can you do it first shot or do you need to make some adjustments after the first shot?

Put up a target the size of the kill zone you are working with and keep moving back until you cannot hit it consistently with your first cold bore shot. Then you have found the range you can shoot to accurately.

Stu.

 

[trueblue]

Mikecr,
Thanks for elaborating. My group, including the first cold bore shot is under 5" at 725 yards.
5 shot group shot as follows:
cold bore shot-
wait 2 minutes
2nd shot, and so on until all 5 shots down range.
Don't know if it is the first cold bore shot to open up the group, as I don't drive down to the target until all 5 shots are down range.
If I waited 15 minutes between shots, it would take over an hour just to shoot one group. This is the first time shooting the 240gr SMK . This is a 3 shot group at 300 yards.

This is at 500 yards.

This is a 5 shot group with the same load at 725 yards.

These groups were shot on different days, under different conditions.
Is there anything in these photos that stands out to help me tighten up my groups? All shot from prone with rearbag.
Also, is there a better way to go about this?

 

[trueblue]

kiwi3006,
I am still in the early stages of load developement. My scope was dialed in for my 210gr Berger load. After shooting low at 500 yards, I dialed it up 3 clicks and reset my turret. I am just beginning to validate trajectory, and see what powder charge groups well at the distances I feel comfortable killing something at. The previous photos were the first time shooting this load at these distances. Rest assured that when all is said and done that I will be dialed in and know where my first shot is going.

 

[Mikecr]

is there a better way to go about this?

For a hunting gun there may be a better way, it's just not easy.
For one, IMO, you're too focused on hot barrel grouping.
I'd be very focused on where them first shots are hitting. Atleast post a cold target aside. Bring it with you for awhile.