Working up loads - Accuracy Testing

todbartell

todbartell

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Got a question for you precision buffs

When working up a load, for long range use (300+), what range do you do your paper testing for accuracy??

I'd think 100 yard groups wouldnt reveal as much as they would for a hunting load. Some bullets dont 'go to sleep' until a couple hundred yards Ive read too

What works for you??
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I work up to my desired velocity at 100 yards, but evaluate accuracy at 300 yards. If I'm looking at ranges in the 800-1000 yards+, I don't start looking at accuracy till I know the bullets are going fast enough to stay supersonic at the desired range.

If I want to compare two loads, I use 3 10 shot groups of each load at 300 yards, alternating between each load. Velocities are always measured and recorded with a Chrony.
 
Tod this is what I do. I load up 15 rounds from my determined maximum load in decreasing intervals of .2gr. I then fire all of these rounds at a target 300 yards out. From this I can usually pic out 2 different accuracy nodes. That is there will be 2 groups where 3 or 4 rounds formed a nice group. I then know that if I load up some loads in the middle of these loads that made the groups it should be accurate. Hope this helps. There is a lot of information about this on www.longrangehunting.
 
In a DCRA/High Power type target rifle, if a load shoots round 10 shot groups at 300 yards, it will shoot at 1000 (in my experience).

In a hunting rifle, I want a premium bullet to stay in 5" at 300 yards with triangular, rather than strung (lineal shaped) groups.

I have found that small groups at 100 can do funny things at 300, particularly in regard to stringing or flyers that won;t show at short range
 
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rg said:
I have found that small groups at 100 can do funny things at 300, particularly in regard to stringing or flyers that won;t show at short range
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Very true. when working up a load for long distance you need to pay attention to getting a load that has as little velocity spread as possible. It won't show up much on a 100yd target but if you have loads where the velocity varies quite a bit it will show up in verticle spread on the targets way out there. If one starts out at 3100 fps and the next round is 3025 the slower one will hit noticeably lower the farther the range. ideally your velocity spread should be no more than 25fps or less if you want to have consistant groups way out there. If you don't have wind flags you will need a very calm day otherwise you might have a good load but the wind will mess up your groups and you won't know a good load from a crappy one.
 
todbartell said:
Got a question for you precision buffs

When working up a load, for long range use (300+), what range do you do your paper testing for accuracy??

I'd think 100 yard groups wouldnt reveal as much as they would for a hunting load. Some bullets dont 'go to sleep' until a couple hundred yards Ive read too

What works for you??
​
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I test all my loads , be them for hunting or targeet, at 200, 300, and 500 meters.

I then shoot the hunting loads at all ranges ( inluding 25 yards) a few shots, to make sure I am happy with them.

In my loong range rifles I generally then get them out to the Outpost range
and fire them at 1,000 to confirm.

Haven't had a problem yet with different POI's or bullets not performing at the longer distances ( or vice versa)
Cat
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I fired 6 groups at 300 yards today with my 260 Remington

groups ran from 1.8" (3 shots) to a bit over 5"

my average was around 3" or so (3 shots)


I found my groups strung horizontal, instead of vertical. Extreme spread on my loads varied from 20 fps to 50 fps (for 6 shot strings of each powder/load).

There was a mirage today, which Im sure doesnt help accuracy, when the target seems to be shimmering non stop! :D :rolleyes:
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abesclaybird@rogers.com said:
I'm thinking about buying a new rifle this year,I don't know which would be the best choice for about 500 to 600 yard shots.I wonder what you people would recomend, all-though I do have a 308w. what els is realy good?
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.308 would work fine. Or you could get into the 6.5mm, 7mm, .338 flavors. If you plan on having a dedicated long range rifle - my pick would be for the 6.5-284.
 
tod, I start all my works up with same lot/brand/fireformed (cream of wheat)/prepped/neck sized brass. I sometimes volume check the cases if concerned with quality. I use mostly US commercial brass and have no issue with making excellent ammo with this.

I load bullets that are accurate enough for my intended use and distance. Many hunting bullets are 1 to 1.5MOA accurate, and will not do any better no matter the rifle or prep work used.

Hornady and Nosler poly tipped bullets are consistently accurate in most rifles I have shot them in. They are capable of 1/2 MOA or better on a consistent basis. I have had many rifles shoot SST's into the 1's and 2's. Not bad for a hunting bullet.

Some have had equal success with premium and 'bulk' bullets. Personally, for LR, I either use Match bullets or the above.

I always use a match primer. It matters for lowering vel variations and stringing. CCI and Fed are excellent. some are using Russian primers but none in Canada yet.

I now use new lot Hodgdon or Reloader powders only. The extruded powders are usually very stable to temp variations (you will have to test your particular lot as things do change), low velocity variations, clean burning, easy to use at warm pressures.

IMR7828 is the only IMR powder that I have used and seen used effectively. Many of the IMR line is made with temp sensitive technology. Any powder that varies significantly as temps change is no good for me. That just screws up all the hard work in load development when the powder itself can vary the same as a 1/2gr or more change.

Surplus powders, especially pull down from decades ago, usually burn dirty and can string excessively. Remember that some pulldown came from machine gun ammo so by design, velocity variations is built in. Some types do work ok with H335 and H870 being the ones I have the most experience with. The new H869 is supposed to be made from new powder tech...we shall have to see.

Assume that all ammo charges are weighed to 1/10gr or less accuracy. Bullets seated straight and to consistent length. Neck tension of at least 2 thou. I prefer 3 to 4 thou or whatever my Lee collet dies give me.

I work up 3rds per 1/2 gr increase. Once I find a sweet spot or two, I will reapproach these levels in 2/10gr increments and go past my sweet spot by 4/10gr unless groups open up. I do this in all case sizes even with something as big as a RUM. Too often, I have seen variations of 2/10 affect accuracy. Some barrels are more sensitive then others.

Even with heavy barreled match rifles, I rarely shoot more then 3 rds groups. Simply because I am consistent in my shooting and technique (ammo was well prepped remember). If the rifle shoots a load, it will do it with EVERY shot.

If the first three go into the same hole, the next 20 will as well unless I miss.

If a group is much larger then what I want AND I am comfortable with my shooting and conditions, that load will never get better. Or be too inconsistent to bother with.

My goals are consistency and repeatability. I use concrete benches, solid pedestal rests with fitting bags front and rear. In the early workup of a rifle, I want to eliminate any and all shooter influence. Trying to shoot 1/4MOA using rests that would be 2MOA at best is simply wasting time and a great way to drive yourself insane.

Same goes for optics. You can't shoot 1/4" groups when you can only see 1/2". High enough mag to see your target properly. Clear enough so that you can see 1/16" or less out to 250/300yds.

Later, I will test under field conditions if that is how the rifle will be used.

I test at 180yds because that is how my range is set up. I pretty much demand 1/2 MOA or less at this range for any type of LR work. If building a full meal deal BR rifle, I will strive for 1/2" groups.

I can also test at 250yds and have found that groups 1" or smaller will usually result in superb accuracy further out. Shooting over a chrony is nice but not always possible. Does help diagnose two great shooting loads. The one with the lowest velocity variations will get the nod.

Because of the components I use, I feel confident that results I see at 180 and 250yds will hold stable as far as I want to shoot. Plus wind is less of a factor then when testing at say 500yds.

Accuracy will tend to reduce as distance increases mostly due to wind and mirage adding to shooter error. However, I know that the rifle and load are capable of hitting small targets at very long distances. That confidence helps me do just that.

Using the above, I have had no issue developing rifles that can hit clays at 750yds consistently if I can dope the conditions. Most of these rifles are out there with CGN members.

Hope this helps.

Jerry

PS if you can, check the runout of cases fired at full pressure. If the chamber is cut right, there will be almost no runout. Measured in three places on the case, you should get 1 to max 2 thou runout. If you get much more then that, the chamber is going to be tough to shoot LR accurately with.

Of course, the throat must be short enough to fully engrave the bullet before it leaves the case neck. Any 'jump' of more then a few thou can lead to pretty poor accuracy. Don't mix up freebore with this jump.

abesclaybird, if building a rifle, the 6BR is simply superb for your intended uses. for a factory rifle, a fast twist 223, 243, 260 or 7-08 would be my first picks with the 270/280, 7RM and 30cal magnums next. The 308 can do ok but recoils more then the ballistics it gives.
 
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Finding a Load

You can actualy do it at 200 yds for a combination of accuracy and
power. Shoot loads picking the load with the least vertical dispersion.
You should find one, that will shoot a level line at 200, then it should
be good all the way out to the longer yardages. 500-600.
If going beyond that take the max. to that yardage and back off looking
for best vertical.
That's my way anyway. But dont shoot beyond 500 here.
 
Mystic, you're an encyclopedia.......
What do you use for your M1A... your site is very helpful. I was really about to feed mine a large dose of Varget. For whatever reason I missed the fact that it is slower than 4895 and even BL-C(2) - in some charts..... Got some Benchmark, 2200, Hdy. A-max ... wich one gives better results for you? How many grains should I expect to use?

Sorry for the hijack.
 
300 yds is good for evaluating the accuracy of a load,your looking for a nice day with little wind and mirage, to get more data the chrono is essential.

I dont agree on the scope magnification being important, it helps but all you need to do is to aim at a target that is appropriate to the sight you are using.

TR shooter's have been shooting 1/2moa at a 1000yds with peep sight for decades.
 
eltorro, thanks for the kind comment. I used Benchmark, Fed 210M and CCI BR2 primers in Win neck sized cases. You will have to adjust the loads to fit your particular rifle but I just used the Hodgdon starting loads and worked up.

I don't remember the exact numbers so best for you to check on the website. Go up in 1/2 gr increments or less. These rifles can be very picky about load amounts.

Jerry
 
agilent_one said:
.308 would work fine. Or you could get into the 6.5mm, 7mm, .338 flavors. If you plan on having a dedicated long range rifle - my pick would be for the 6.5-284.
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6.5-284 is an awesome 1K round but they are a barrel burner.

My fellow addicts are all switching to 284 for 1k and are trying to persuade me to go along. Me, I like 308 for 1K but I am pretty sure there is a 6.5X47 Lapua in my future somewhere.
 
I work up loads at 100yds then test at 300 meters. If a loads sucks at 100 it is unlikely to turn into a winner at 300M. If there is any wind at all, I ignore horizontal dispersion if testing a load at 300 and I don't try to correct for wind. I will note wind variations to get an idea of effect, but I don't try and correct for wind until I'm pretty sure the load shoots well enough. Regards, Bill.
 
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