Hi Guys,
I was working up a new load for my son's new .243 and something interesting happened. Shooting progressively hotter loads and comparing group sizes and velocity spread. I would exspect the loads with the most consistant velocities to have the smallest groups. That is not what I saw on the targets and chrony. Any Ideas?

Gene

What distance? Dutch.

That is common, there are so many factors that come into play such as temperature,humidity and wind. The other things like consistency, barrel heat,time from shot to shot,time round keep in chamber before firing,shooting with the same conditions. Good Luck

When the bullet starts down the barrel, the barrel begins to vibrate. The muzzle gyrates in a very oblonged "figure 8" pattern. (Imagine the mathematical symbol for infinity).

What you want is for the bullet to exit the muzzle when it is on one end or the other of this "figure 8." That is the most stable and forgiving area.

If your bullet exits in the straightaway of this harmonic whip, you'll have a string of shots, usually in a straight diagonal line. When you see this diagonal line, that's telling you that your load is not coinciding with the barrel's harmonic whip.

You can load a little hotter, or a little lighter, or you can simply try seating depth adjustments to get the muzzle exit time optimized.

You may have heard that it is best for the bullet to exit right in the center of the "figure 8," but that's not correct. If you'll think about what I'm saying you'll see why. The end of the figure 8 provides the slowest, stablest, and closest knit pattern, and it is here that you want your bullets to exit.

Even though you were getting pretty uniform velocity from some of the loads, if the bullets were exiting in the straightaway of the figure 8 they would not have printed consistently.

I'm going to reprise below a synopsis of my load development method which will allow you to quickly find what I call the Optimal Charge Weight (OCW) for a given load recipe. If you'll understand and follow these instructions you'll arrive at an extremely accurate and resilient load.

For those already familiar with this load development method, you can stop reading here!

**************

What it basically is is a sort of "modified Audette" method. For those unfamiliar with the Creighton Audette method his was a method of load development which consisted of shooting at a distant target, some 300 yards away if possible. One shot of each charge weight variation was fired at the bullseye at the 300 yard target, and if all went well, a vertical string formed on the target as the increased charges were fired. Somewhere along that vertical string should be a "cluster" of three or four shots that hang together, indicating the most stable area of charge variations, and therefore (presumably) the best amount of powder to put into that load.

The problem I and many others have found with the Audette method is that useful information often eludes. Sometime (perhaps more often than not) no cluster, and often no intelligible vertical string even forms.

I've developed the following method which I believe is an excellent way to arrive at the OCW, or optimal charge weight for a particular load recipe. I define the OCW of a load recipe as the amount of powder which ignites and burns most consistently in that application. I believe that for any given cartridge recipe, there is a specific amount of that powder which will yield the best consistency.

This method has worked beautifully for several loads I've developed for the .270, the .308, and the .243. Others have had good fortune with .223 loads using this method.

I'll tell you about the latest OCW load I developed for my .243, a Remington 788. The bullet was the Sierra 60 grain HP, and the powder used was IMR 3031. Primers were the CCI 200's, and brass was all twice fired Winchester.

In checking three loading data sources, I noted that 39 to 41 grains of IMR 3031 was the max charge zone for IMR 3031 with 60 grain bullets in the .243. I have found that the best loads for all of my own rifles have been loads that were at or near listed maximums, but I do test about 5 per cent below for pressure signs, then work up.

I began with three rounds each of five different charges, graduating in .3 grain increments. The tested charges were 39.2, 39.5, 39.8, 40.1, and 40.4 grains.

I cleaned the rifle, and shot two fouling shots and allowed two minutes for it to cool. I had five targets posted at 100 yards, one target for each charge variation.

I shot one round of the 39.2 grain charge at target 1, allowed two minutes for cooling, and then fired one shot of the 39.5 grain charge at target 2, cooled, one shot of the 39.8 grain charge at target 3, cooled, you get the idea...

This is basically a "round robin" system of grouping each charge, which precludes disadvantaging late groups due to fouling, or heat build up.

When finished, I had three shots on each of the five targets, BUT (!)... I don't look for the tightest group of the five and call that my load.

Here's what I do instead, and I'll explain why later: I look for the three groups of the five that come the closest to hitting the target in the same position. I noted that in this case, the three center groups were the ones which happened to hit the same POI, (all within about 3/4") with the 39.2 grain group hitting low and left from that common POI by an inch. The 40.4 grain charge, in addition to moving high and right of the common POI for the three center charges, opened up in size to about 7/8". The 39.2 grain charge shot about 1/2", but as I said, it wasn't near the common POI that the 39.5, 39.8, and 40.1 charges shared.

So I concluded that the best charge for this application was 39.8 grains of IMR 3031. This was the charge that would allow 39.5 grain charges and 40.1 grain charges to group right with it.

Why would I want that?

Well, variations in brass cases, powder lots, outside temperature--and other things can cause your load to increase or decrease in pressure. With the OCW load, you're covered for a significant amount of pressure differences that may come into play. If I'd gone with the 39.2 grain charge, a *slight* rise in pressure, brought on by an odd brass case or a hot day, etc., would have resulted in a 1 MOA deviation high and right of my POA.

I shot a 1.5" group at 300 yards with my .308 load with the 168 grain Sierra Matchking using one shot of 43.3 grains IMR 4895, one of 43.6 grains, and the third shot in the 1.5" group was charged with 43.9 grains. (The OCW being 43.6 grains, of course).

If you want to test the resilience of your own pet load, just load up a 1% increased charge, and a 1% decreased charge, and fire those two loads into a three shot group with the standard charge and see how it goes. In many cases, you'll find that either the low or high charge will group with the standard charge, but not both. This should at least tell you which way to go with redevelopment.

Oh yeah, I almost forgot. How does one tighten the group after deciding on the OCW for their load? OAL adjustment is the way. Seating depth should be, in my opinion, the fine tuning tool used last, not first as is classically done. I've gotten kudos from Gerard Schultz of G.S. Custom bullets for this method of loading, as he says he uses a similar method wherein OAL adjustments are made last of all to tune for the tightest group.

Good luck with your .243, and let us know how things go.

Dan Newberry
green 788

Wow!
That is nowhere close to what I was doing. I can see the error of my ways.
This method is taking a while to digest. Great idea! Back to the range I go. After this weekend's scouting trip.
Thanks again
Gene

Gene,

This method is a bit unconventional, but everyone who has tried it has reported good results.

What powder and bullet are you using? You will want to select five to seven charge weights near and including the maximum charge. I usually just go with the max, and count backwards in .3 grain increments.

You do of course watch for pressure signs along the way...

Let us know how it goes,

Dan Newberry
green 788

This is not unusual. The Lyman Handbooks always selected their "accuracy load" based upon uniformity of velocity, NOT BY GROUP SIZE, and I often found that the so-called "accuracy load" WAS NOT the most accurate!!

I'm loading 90 gr nossler balistic tips with IMR 4350 in 39.2 to 41.5 grains. this range was all the "Good," shots from a set shot 3 rounds at each target. (through a progressively hotter and more fouled barrel at 50 yds) I'll work with the modified Audette method this weekend and get back with you next week.

Thanks again
Gone camping/hunting
Gene

The IMR 4350 should do an excellent job with the 95 grain Nosler BT's, and you're right where you need to be with the powder charge range.

I'd load three each of 40.5, 40.8, 41.1, 41.4, and 41.7 grains. (The 41.7 grain charge should be fine to fire if there are no pressure signs at 41.4 grains.

You're going to find the OCW somewhere around 41.4 grains, based on Nosler's accuracy load which is more often than not right on the money. After you find the three groups that hit virtually the same POI, you will of course then choose the powder charge of the center group as your OCW. If the size of these groups isn't reasonably tight (1.5 MOA or better) you may want to select a different powder or bullet, but I'm thinking the combination you have is going to work pretty well.

Remember to fine tune the group with OAL adjustments. If the group is over an inch, I'd try a primer change first. If the group is 3/4 MOA or so, slight adjustments in the bullet's seating depth can do wonders for tightening that up.

Please post back as soon as you have your results.

Dan Newberry
green 788

Made it to the range. When I got home I over laid the targets, aligning POA, and penciled in the shots from the adjacent targets and looked for the best 9-shot group. My best group by far was the last one with only 6 shots on it. Back to the reloading bench to cover this area better. (41.5 -41.8)

Back to the range. Windy, Oklahoma day shooting east with southwesterly wind. Halfway through the phone rings, #1 son in accident. Quick pack-up and back to town. Nobody hurt, he was stopped at red light, next truck pushed him into the intersection. Bumpers did their jobs.

Next day back to the range. Wind strong but southeasterly now. Finished shooting the set.

There were a couple of good groups. (41.4 and 42.3) The hotter load was a definite string and the milder group was nearly round. I’ll set my scale for 41.4 and start playing with seating depth.

Any ideas?
Gene

How far is the 41.1 grain charge away from the 41.4 grain charge?

Since the 41.4 and the 41.7 printed together, you may find that 41.7 is the OCW in this case. The only way to confirm that is to fire a group with 42.0 grains as the charge and see where it prints in relation to the 41.4 and 41.7 grain groups.

Do this only if there were no pressure signs at 41.7 grains. I'm betting that the 42 grain charge will not deviate far at all from the 41.4 and 41.7 grain charges, which would mean that 41.7 is your OCW.

After firing the 42.0 grain group, fire another group consisting of one shot charged with 41.4 grains, one shot of 41.7 grains, and the third shot with 42.0 grains. If all is well, you'll have an MOA group in spite of the .6 grain charge difference.

Conventionally developed loads will not normally pass this test.

Sounds like you're getting there...

Keep me posted,

Dan Newberry
green 788

Dan,
I had 7 targets worth of rounds loaded (21), Shot round robin one load for each target with the real world problems mentioned earlier. Then overlaid targets (aligning POA) and marked the POI's on the adjoining targets. Therefore targets #1 and #7 had only 6 marks on them. The 9-shot group centered around 41.4 on target #3 was the small oval shaped group. The 6-shot group on target #7 was tight but very straight. The last set was at the max load listed for a 90 grain bullet in the Sierra manua l4th ed. My older Nosler manual does not list the 90 grain bullet. My Hornady manual covers a 87 grain bullet but no IMR 4350. I have no pressure signs and stopped at the Sierra Max.

I was skipping the max load set as a OCW because the results were so linear. My guess is that this load range is exiting the muzzle on the middle of the barrel vibration. Or am I seeing more than is realy there?

Thanks for all the help.
Gene

Add a little more information. I just got word that the new Nosler manual lists 41.5 as the max and most accurate loads.
Gene

My secret is out!

What you've noticed is exactly what prompted me to develop a loading method designed to find these universally good load recipes. I kept noticing that, more often than not, Nosler's and Sierra's accuracy loads would perform well in most rifles chambered for those rounds.

Add to that the existence of certain factory loads that seem to work wonders in the vast majority of rifles chambered for them.

Since we know that overall length (bullet seating depth) is uniform on factory loads, it occurred to me that they were getting this excellent performance with the correct powder charge, a charge of powder that would ignite and burn most uniformly in the recipe at hand. This I called the "optimal charge weight," and decided to find a load development method designed around finding this powder charge in a given recipe. Such a recipe would burn so consistently that even if the bullets exited the muzzle at an inopportune moment, at least this moment would be consistent, producing at worst a short linear string, but still MOA or close to it.

I think we miscommunicated a bit initially here. I assumed (yeah, I know ) that you were talking about the 95 grain Nosler bullets, since they don't offer the 90's in the ballistic tips now. Normally, though, when you lighten the bullet, you're going to need to increase the powder charge to get the load density (and usually accuracy) back up.

If I'm understanding you correctly, you're shooting 90 (not 95) grain Nosler ballistic tips with 41.4 grains of powder and getting nice, tight groups. And, if you fire a 41.1 grain charge into that nice tight group of 41.4 grain charged shots, it will print inside MOA of that group. Lastly, a 41.7 grain charge will also print into this small group, even though it is .3 grains high. If that's where you are, you are THERE!

Is this correct?

Dan Newberry
green 788

Thanks Dan. I'll try this over the next little while with various calibers and let you know what happens. - Dan

[ 10-04-2002, 20:30: Message edited by: dan belisle ]

Dan,
The 90-grain Nosler ballistic tip is new to the best of my knowledge. It shows up in Nosler’s #5 manual not #3 or #4. I took my empty box back to the local gun shop today. They needed convincing that they ever sold 90g NBT's.

My short string was the shots around 42.6 grains IMR 4350. Which is Sierra’s max load for their 90-grain bullet. I had no pressure signs approaching or at 42.6. I think I can get along with 60 fps less and keep the throat from eroding a little longer.

When you test seating depth, how far do you go? I Started at the lands and set deeper by � turn for a full turn.

I'm aproaching MOA at 100m. I'm finishing up Remington Crisp now and the trigger pull feels much better.

Thanks
Gene

I just checked my Nosler #5 and you're right! I didn't realize they were making the 90 grain BT now, and merely assumed that you were shooting long ago discontinued bullets! Sorry about that...

Anyway, when you say "short string," what exactly are you referring to? Do you mean that you got a short vertical or diagonal line with these three shots? Where in relation to the 42.6 grain group were the 42.3 and 42.9 grain groups? The manual says that 43.5 grains is the max. If the 42.6 and 42.9 grain groups printed together, and you haven't tested 43.2 grains, you may want to. In this scenario, your OCW would be 42.9 grains.

I usually vary OAL by .005", and I shoot the short ones first. This way, if I find that groups are tightening as the bullet goes deeper, I can take the long loads home and simply seat the bullets to the length that worked best. This saves material.

I'm still unsure whether the 41.1, 41.4, and 41.7 grain string clustered together or not. In other words, what would the overall group size of the 41.1, 41.4, and 41.7 grain loads (9 shot group) be if all overlayed?

Thanks for sharing your information...

Dan Newberry
green 788

I'm still unsure whether the 41.1, 41.4, and 41.7 grain string clustered together or not. In other words, what would the overall group size of the 41.1, 41.4, and 41.7 grain loads (9 shot group) be if all overlayed?

I overlaid each target with the targets on either side in the load progression. That made it easy for me see wich one's grouped together.
So all the targets have 9 marks on them except the two end ones wich have six marks. There was a good 1.25" group on target #3 wich has 41.1, 41.4, and 41.7 shots on it.

I checked with a friend who has Nosler's new book. He may have answered for the heavier bullet.

The string around 42.6 was just under 2".

Gene

Okay. I'm a little slow sometimes, but if you're patient with me, I'll catch on.

So 41.4 grains looks like where you want to be.

I would load up 18 loads with the 41.4 grain charge, and begin the OAL testing, as you mentioned. Load three each of .015", .010", and .005" under the OAL used in phase one of the test, and load three more groups of three, representing .005", .010", and .015" over the phase one test OAL.

Important! What primer are you using? You may have already mentioned it, but I've forgotten. If you are using the WLR Winchester primers, you can cut your groups by 1/4 to as much as 3/4 MOA by switching to a cooler, more consistent primer. The CCI 200, the Federal 210, or the Remington 9 1/2 are all much better in my experience.

With the 18 loads, load in .005" increments, three graduations above, and three graduations below the OAL you've already tested. I don't see any reason to load any cartridges with the OAL you used in the first part of the test.

Begin with the shortest, and fire all three of those at one target. I know this will be getting away from the "round robin" system, but this will be necessary to avoid shooting more rounds than might be necessary.

If you note that the shortest group is very tight, and the groups open up as the OAL gets longer, stop before firing them all. You can shorten the long rounds later on.

The 9 shot 1.25 MOA group is very encouraging, and I'm certain it will tighten considerably--especially if you're currently using WLR primers and you switch to one of the primers mentioned above.

If the rifle isn't bedded, you can use the USRAC factory trick of putting a dab of hot glue in the recoil lug channel. It keeps the action from shifting, and will do until a glass job can be done in the future. Apparently USRAC (Winchester) believes it will do for all time!

Please keep the info coming. The 41.4 grain charge does seem to be the recipe.

OAL tuning (and ix-naying the WLR's if you're using them) will get the rifle below MOA for sure...

Dan Newberry
green 788

WLRs are prepped in all my Remington brass.
Did I mention the local shop is out of bullets!
I can do the 18 round test but will be 3/4 of my stash.

Gene,

I think you've definitely got a shooter on your hands here.

With a double handicap (WLR primers and Remington brass! ) you're still shooting 1.25 MOA. That's like running a marathon blindfolded with a rock in your shoe and coming in third! Not bad at all...

Winchester brass, and Remington primers... That's where to be, and believe me, you'll see a difference.

You may not need to waste 18 rounds here.

You mentioned an "oval" shaped group, and I'm assuming that the 9 shot 1.25 MOA group (41.1, 41.4, 41.7 grains) took this shape. Bedding issues cause groups that "split," or string out. Well rounded, enlarged groups tell me that your rounds have too much runout (Remington .243 brass, guilty as charged!) and/or the primers need to be more consistent.

Saeed and company have tested all the major rifle primers, and have concluded that Winchester Large Rifle primers should be renamed "Winchester Large Group primers!" You should still be able to access this info from the homepage of this site. Saeed's experiences with the WLR primers have been the same as my own.

Also, with the Remington cases, runout is likely to be excessive. I've tested two different batches of Remington brass in the .243 (my 30-06 Remington brass is fine) and found that the case necks varied too much in thickness to keep the runout at .004 or better. I'd really prefer .003 with a 24 caliber bullet.

If you have a concentricity gauge, you can check the integrity of the Remington .243 brass. I'm pretty sure you're going to find runout in the .005 and higher arena. This much runout would take a 3/4 MOA group well above MOA.

Try this: Scrounge around and find a few Winchester .243 cases (you know, it was Winchester that put Remington's .244/6mm to pasture with their excellent .243, so I've always sort of felt that Remington was taking a quiet revenge on .243 win shooters by deliberately screwing up their .243 cases , but I can't prove it).

Then beg or borrow a few primers, such as CCI 200's, Remington 9 1/2's, or Federals...

Put together about eight or a dozen rounds using the same OAL you were using in the first part of this development.

If these loads don't shoot tighter than MOA I'll eat my keyboard, and wander off kicking rocks and talking to myself.

Change the brass and the primers, and you'll probably be there. I know this probably sounds frustrating, but you've already done the hard work here. Good cases and good primers will only improve things.

Dan Newberry
green 788

[ 10-05-2002, 16:03: Message edited by: green 788 ]

Frustrating?
I thought I was having fun!

Dan,
I'm with you on the Rem 9-1/2 primers. They pulled the groups around 42.5 to the best set. The question of wich brass is better is still not clear to me. I picked up some win brass to play with and can't really prove any difference yet (other than much less primer seating pressure.
Now the last minute has passed, it's time to go hunting.

Later
Gene

Thanks for the update, Gene. I really like the Remington primers for accuracy. Ditching the WLR's normally does tighten things up some, or a lot...

Your Remington brass might be from a pretty good lot. If I were you, I wouldn't get hooked on it, though. I've gotten a couple of lots of it that had horribly uneven case necks, which resulted in runout numbers over .007".

I do have about 40 Remington 30-06 cases which are excellent.

Congratulations! Mission accomplished ...

Dan

In many case, and particularly with slow burning powders the hotter the load the more accurate, but you cannot depend on that..

The ONLY way to find your most accruate load is to shoot groups, 3 five shot groups usually tell the true story, all else is TWADDLE.....