Load Testing at What Distance?

Handloader · Posted: Fri Mar 17, 2006 1:29 am Post subject: Load Testing at What Distance?

Bullets can stabilize or destablize between 100 and 200yds. It is not uncommon to find that the 100yd accuracy can improve at 200yds or vice versa. I have two rifles that shoot MOA at 100 and 1/2 MOA at 200, IOW, the same size groups. With one other, accuracy deteriorates.

Often we have reloaders come into the store and show us targets where group sizes more than double between the two distances. Sometimes they are triple or quadruple the 100yd groups. Less common is for a rifle to shoot the same size group at both distances, but, we see that as well.
Barrel/rifle quality, conditions and optics play a role here as well as the shooter's bench techniques. That said, I believe that some bullet's yaw will settle down or be amplified as it continues downrange.

I believe testing for accuracy at 200yds is more revealing than 100yds and a more valid indicator.

Spacedone · Member Joined: Nov 04, 2005 Posts: 266 Location: missouri

i find that depends on the bullet design.

short range bullets {round nose} i like to group at 75 yards and at 150 yards.

long range bullets i like to group at 150 and at 250 yards.

i find that when i do this using a scope that i get the best consistancy with all loads i use.

now remember this is for hunting.

for target shooting i set my round to shoot best at the range i will be shooting most.

for practice/target shooting i want 1 inch or less groups but for hunting large game im more concerned with hitting the kill zone {6 inches} while retaining the most energy for the max range i expect to shoot {300 yards}

i use for large game 60 year old enfield war guns and can achieve 1 inch groups at 200 yards off a bench with max energy about 1800 Foot pounds.

350 yards being my guns max effective range against elk sized game.

i find setting my scope to shoot 1 inch high at 50 yards allows me to hit the kill zone at longer ranges {300 yards} more reliably. ie 1 inch high at 50 yards allows me to drop my bullet into the target with the least amount of percieved drop {10 inches} at 300 yards.

i believe there is a difference in target accuraccy and hunting killability.

Crackshot

Pick your bullet, load some rounds, check accuracy at 100,200,300. If they do not performe at all above stated distances, I switch bullets till they do, I also taylor the bullet to the game"we all know that" be supprised how many dont know that!

Coyote_Hunter_

Handloader wrote:

Bullets can stabilize or destablize between 100 and 200yds. It is not uncommon to find that the 100yd accuracy can improve at 200yds or vice versa. I have two rifles that shoot MOA at 100 and 1/2 MOA at 200, IOW, the same size groups. With one other, accuracy deteriorates.

Often we have reloaders come into the store and show us targets where group sizes more than double between the two distances. Sometimes they are triple or quadruple the 100yd groups. Less common is for a rifle to shoot the same size group at both distances, but, we see that as well.
Barrel/rifle quality, conditions and optics play a role here as well as the shooter's bench techniques. That said, I believe that some bullet's yaw will settle down or be amplified as it continues downrange.

I believe testing for accuracy at 200yds is more revealing than 100yds and a more valid indicator.

At my range there is a distinct disadvantage to shooting for accuracy at 200 yards â€“ the wind. It is a rare day when it stops gusting at the 200-yard range. Since wind deflection is non-linear, the deflection at 200 yards can easily be 400% greater than at 100 yards. Might explain some of those 200-yard groups you are seeing, too.

While I have heard the claim before, I have never subscribed to the belief that a rifle will shoot better at long ranges than at short ranges, in this case 1MOA @ 100 and 1/2MOA at 200. The physics would not only require that the bullets would somehow alter course in mid-flight, but that they would all alter course toward the same point! It is my belief that there are other factors a work. I know that I have shot groups with a smaller MOA measurement at longer distances and I know it had NOTHING to do with the bullets altering their path in mid-flight. In my case the explanation could be found in the sighting devices and targets used, which were simply a better match at 200 than at 100.

Regardless, I think it is a good idea to check accuracy out as far as you are willing to take a shot at game. You might find out that a 400-yard shot is no big deal under the right circumstances and you might find out that you have no business shooting past 200. (In which case the remedy is generally more practice.)

JO422 · Member Joined: Sep 16, 2005 Posts: 33

I've seen the same thing happen that Handloader mentioned. The cases that I have seen is bullets that shoot a larger group at 100 yards (1.5 moa) and they the n have a significantly better group at 200 yards (.33 MOA) and then .5 moa at 300 yards. Invariably this has been with heavier bullets that are being shot with a realtively slow rate of twist in the rifle barrel. The rifling failed to stabilize the heavy bullet at 100. By the time it reached 200 yards the bullet was stabilized and showing what kind of accuracy the rifle was capable of.

A way to solve the 100 yard poor grouping delimma is to use lighter bullets that match the twist rates of your rifle barrel. You will need to experement, as each rifle has its own preferences. I have 2 identical rifles in .223 with barrels from the same manufacturer. One likes the SMK 52 gr while the other prefers a 55 gr Sierra Blitz King.

PaulS

The rpm of a bullet changes a lot slower than the forward velocity does. Usually too fast a spin will cause accuracy problems at close range but will "settle in" between 100 and 200 yards. I have never seen a bullet that was stable at 100 become unstable at 200. I am a believer in faster twist is better - for that very reason - and I have had very good luck with bullets that should have fallen into the "over-stablized" group. A good example of this is a 358 Winchester that I have with a 1:12 twist. It is set up for the 180 grain Hornady spire point and the Speer 180 grain flatpoint bullets as ideal. I loaded some 158 grain JHP pistol bullets at 2500+ fps and found that they grouped at .33 at 100 yards and 5/8 inch (.625) at 200 yards.
It surprised me because I expected these to be spun so fast that they would be ok for plinking but these are sub caliber groups at 100 yards and nearly 1/4 MOA at 200 yards. If the bullets were a bit better constructed I could hunt with them - If I wanted to limit my shots to head and neck shots I could easily hunt game - large and small - with this round. The expansion of the 158 grain bullets is explosive! They turn to fragments in 8 to 12 inches with the base (58 to 61 grains) going to a maximum distance of 15 inches in my Fackler box using salt water.
The 180 grain bullets are vey good at 2700 FPS for large game and the Speer produces slightly better groups.

popgun

I have seen the difference in accuracy improve at 200 and 300 over the 100 yard groups.

I recently read Dan Newberry's article about Optimal Charge Weight (OCW Method of Load Development). It is a very interesting article and I recommend that you guys read it and even do some testing yourself. I have not had the opportunity to try the OCW method yet but will try it on a couple of rifles that I have rounds loaded up and ready for testing using his recommendations. Shucks! I will try anything to squeeze out a little better accuracy out of my rifles. Very Happy

Here is the link to the article

Dan Newberry's article on the OCW Method of Load Development

After you read the article I think you will see the reasons we see the accuracy improvement at 200 and 300 in some guns and not in others. His reasoning is that the wrong accuracy node was chosen when developing the loads in the guns that did not show good accuracy at longer ranges. I know that I have seen more than one accuracy node when developing loads at the range. He and his friend, Engineer Chris Long, have put allot of work into the testing of his theory and it seems to have merit.

1895ss

Very interesting article popgun, it certainly looks like it's worth checking out. Thanks

Handloader

The OCW information is available on this website as well. Check it out under "articles" on the home page. I believe there is merit is some of his conclusions.

Townsend Whelen also conducted experiments on bullet yaw and found enough evidence to conclude that under some circumstances bullets stablized further downrange. The example often used is that of the old fashioned top, the one that had you winding string around it, then throwing in on a hard surface. Often, initially, the top would wobble upon landing and then balance or center itself, the, go unstable as the spin rate decreased. Perhaps, something similar is occuring with firearms as well.

Gil Martin

It depends. With centerfire rifles I start at 50 yards then move to 100 then 200 and rarely shoot at 300 yards. We just do not get many 300 yard shots around here. If I were going out west or up north, I would try 300 yard shots. All the best...
Gil

PaulS

I test loads for more things than just grouping. What I test for determines the range at which I test them.

I check group size first at 100 yards - that is the range that most of my shooting is done and hunting shots are usually within that range as well.

I test my loads for penetration and expansion at 25, 50, 75 and 100 yards in a salt water Fackler Box.

I test for velocity at 5 yards

I test for consistancy at 200, 100 and 50 yards over a long period of short sessions with 10 or less rounds fired at each of the many sessions.

Handloader

PaulS wrote:

I test my loads for penetration and expansion at 25, 50, 75 and 100 yards in a salt water Fackler Box.
.

Hi PaulS

Please tell me about "Fackler Box". I don't know what it is or how it is constructed.

Thanks

PaulS

Handloader,

A Fackler Box is a framework to hold one gallon freezer bags filled with water - in my case salt-water. The concept is that you fire a bullet into the end of the box and it reacts as it impacts the bags in a way that is proportionally consistant with the bullets impact with soft tissue in game.

Testing the integrity and penetration in this way gives repeatable and consistant evaluation of a bullets capability on game when fired into the soft tissues of the vitals. When different bullets are fired into the same media the results can be compared in a manner that is representative of real life results.

Deleted_User_2665 · Super Member Joined: May 06, 2006 Posts: 380

Quote::

A Fackler Box is a framework to hold one gallon freezer bags filled with water - in my case salt-water. The concept is that you fire a bullet into the end of the box and it reacts as it impacts the bags in a way that is proportionally consistant with the bullets impact with soft tissue in game.

Testing the integrity and penetration in this way gives repeatable and consistant evaluation of a bullets capability on game when fired into the soft tissues of the vitals. When different bullets are fired into the same media the results can be compared in a manner that is representative of real life results.

I do the same thing and for the same reasons Paul S describes with a row of 1 gallon plastic jugs lined up on a wood plank set on two cider blocks. A round is fired into the front jug at whatever yardage and if all goes well the bullet is trapped inside one of the jugs further down the line....usually I would expect about 6 or 7 jugs to be penetrated with say a .270 win with 130 grain bullets at a practical upper end velocity......at 100 yards.

Seems to me with my experience at that it would take more than one 1 gallon bag to trap a bullet at 100 yards from a valid big game contender...but I dunno. I use regular un salted water.....does the added salt give that much more density to the liquid to stop a bullet inside one gallon..??

Just curious........

rpakelly · Rookie Member Joined: May 01, 2006 Posts: 2

Wildswalker, I think you misread his post. He has more than one , one gallon freezer bag. More like the number of one gallon milk jugs you use.