Strange Results with New Load

[markg]

I had an opportunity to test out a new load I have worked up with my Ruger Precision Rifle in .243. The results were very strange. I am looking for some explanations.

I was using a magneto speed Chronograph so i think the Data should be pretty accurate. The question becomes how do I interpret the data.

I am a very serious reloader. I measure every powder charge to the 0.10 of a grain and double check the charge against a beam scale. I use redding full length and bushing neck sizing dies. I am using Lapua Brass and H4831sc powder. I have a hornady LNL case overall length gauge and I am definately not touching the lands. I am shooting Hornady 105gr Amax bullets. The powder is a couple of years old.

My velocity results are as follows.
41.5 grs 2827 2829 2897 2813 with a SD of 32 and ES of 84
42.5grs 2892 2904 *2691* 2931 one error SD 107 ES 240
not including the strange shot it was SD 16.31 and ES 39

43 grs 3639 2886 2897 2927 2892 SD 295.73 ES 753
not including the strange shot SD 15.79 ES 41

I also shot some Federal blue box 100 gr soft points and frankly they performed better then my "precision custom ammo"

2925 2906 2962 2932 error SD 20.14 ES 56

So did my chrony fail or is the .243 just a really wonky cartridge to reload for? With my 7mm i am able to reload ammo that gets a SD of 4 and ES 10 so i know what i am doing.

When seating the bullet it was a bit tight but i just attributed this to using quality Lapua brass but i had full length sized these rounds. Maybe that was the problem? I have some of the same brass that is neck sized only.

I just cant figure this out?

[catnthehat]

You could try twin things
Try changing powder
Or check your results on the target and enjoy st the same time forgetting about what the chronograph says!

Seriously though a few rounds ls not a true sampling of the factory stuff
Cat

[markg]

Originally Posted by catnthehat

You could try twin things
Try changing powder
Or check your results on the target and enjoy st the same time forgetting about what the chronograph says!

Seriously though a few rounds ls not a true sampling of the factory stuff
Cat

Could it be a bad lot of powder?

[catnthehat]

Originally Posted by markg

Could it be a bad lot of powder?

It could be, but the only way to tell for sure is to do more testing and with a different lot as well
Cat

[Dick284]

Could be that your seeing the results of pressure spikes which the .243Win and heavy bullets are famous for.

[Robmcleod82]

Try changing the batteries in your magneto speed and making sure it's not mounted too low. The only time I've ever had errors with min has been when it's come loose or sitting a little too low. The 3600 shot is way too fast that would point me in the direction of batteries in poor health.

[Salavee]

Originally Posted by Robmcleod82

Try changing the batteries in your magneto speed and making sure it's not mounted too low. The only time I've ever had errors with min has been when it's come loose or sitting a little too low. The 3600 shot is way too fast that would point me in the direction of batteries in poor health.

This

[densa44]

You are very careful and your results are very good. I think that the powder is not uniform. I'd shake the bottle up well before I used anymore of it.

I shoot a 243 with lighter bullets and use Varget and IMR. I think I loaded Benchmark.

The results that I have the best results with are the powders that pour like sand.

What I would really like to know is what the SD's would be with different powders. I've never seen the manufactures publish any info like that.

So if you do any more experiments with the same care you are taking I'd love to read the results.

BTW Variation in the powder is something I've always suspected.

Thank you for this post and your hard work.

[Pathfinder76]

The extremes are chronograph issues. There is no way that is pressure spike issues. If it was you would have locked things up solid.
It is not bad powder either. It is a load combination that produces larger extreme spread than you like. It happens.

[elkhunter11]

If the 3600+ reading was real, there would be obvious pressure signs I suspect an issue with the chronograph mounting or batteries.As far as the higher SD goes, that is likely just a result of the load combination..

[markg]

Some great ideas so far thanks guys.

Next reloading session will be with a new can of powder I recently purchased. I will also be replacing my battery in my magneto speed. I will also try some neck sized brass and compare it to the full length. Maybe the tension was to high from the one die. If that doesn't work then Dick might be right and it's a function of the cartridge. Thanks again guys for the great solutions. It was just what I was looking for. Sometimes when your in the situation you can't see the trees for the Forrest.

I'll post new results when I,am finished testing the new loads.

[elkhunter11]

Originally Posted by markg

Some great ideas so far thanks guys.

Next reloading session will be with a new can of powder I recently purchased. I will also be replacing my battery in my magneto speed. I will also try some neck sized brass and compare it to the full length. Maybe the tension was to high from the one die. If that doesn't work then Dick might be right and it's a function of the cartridge. Thanks again guys for the great solutions. It was just what I was looking for. Sometimes when your in the situation you can't see the trees for the Forrest.

I'll post new results when I,am finished testing the new loads.

The pressure required to produce over 3600 fps would at the least blow a primer, with obvious brass flow. Quite likely, you would have a very hard time opening the bolt. If there are no obvious pressure signs, then the 3600+ reading is false.

[Pathfinder76]

Forget a "new can" of powder. Use a different type of powder altogether.

[CaberTosser]

Unless you felt a major recoil difference when shooting the 3600 fps shot then it would stand to reason it was not actually going 3600 fps.

[bobinthesky]

Originally Posted by markg

Some great ideas so far thanks guys.

Next reloading session will be with a new can of powder I recently purchased. I will also be replacing my battery in my magneto speed. I will also try some neck sized brass and compare it to the full length. Maybe the tension was to high from the one die. If that doesn't work then Dick might be right and it's a function of the cartridge. Thanks again guys for the great solutions. It was just what I was looking for. Sometimes when your in the situation you can't see the trees for the Forrest.

I'll post new results when I,am finished testing the new loads.

Only change one thing at a time if you really want to know what is causing the problem.

[markg]

Originally Posted by chuck

Forget a "new can" of powder. Use a different type of powder altogether.

According to a lot of competitive shooters this powder bullet weight has produced good results. My gun might be different and you might be right.

For the heavy bullets, in the 100-115 grain range, modern slow-burning extruded powders produce great accuracy with low ES and SD. With the 105-107 grain match bullets, try H4831sc, Reloader 22, Reloader 25, and Vihtavuori N165. Sierra’s recommended Hunting Load for its 100gr soft-point FB and BT bullets is 36.2gr IMR 4064 at 2900 fps. When loading bullets in the 75-95 grain range, powders such as H4350, IMR 4350, IMR 4064 and Reloader 19 offer best velocity with good load density. Many long-range varminters recommend H414 with the 87gr V-Max. For the light varmint 60-75 grain varmint bullets, you can use faster powders, such as Hodgdon Varget, H414, and Vihtavuori N140. For the 70gr BlitzKing, Sierra suggests a load of 38.6 grains N140 at 3200 fps. Maximum velocities with the lighter bullets can be achieved with ball powders such as Winchester 760 and H380. Click Here to download Sierra Bullet’s complete .243 Winchester Load Map as a .pdf (Adobe Acrobat) file. With data for two dozen powders, this provides suggested loads for Sierra’s entire 6mm bullet line-up from 55 to 107 grains.

Taken from accurate shooter web site

[markg]

Originally Posted by elkhunter11

The pressure required to produce over 3600 fps would at the least blow a primer, with obvious brass flow. Quite likely, you would have a very hard time opening the bolt. If there are no obvious pressure signs, then the 3600+ reading is false.

There was no difficulty with the bolt lift. Good point about pressure with the huge velocity jump.

[Ebrand]

I suspect your chronograph mis read something on the one shot.

Where did they go on the target?

[markg]

On the target I would get 1 or 2 shots touching then one pretty close (1/2 group ) then i would get 1 or 2 farther out bringing the group to just over an inch. I became a bit frustrated and think that may have affected my shooting. I unfortunately allow my emotions to affect my shooting.

PS i suck at golf for this same reason.

[Dick284]

It's simple.
Quite thinking so much, and just shoot.

"Muscle memory" will start taking over, and you'll settle into your form.

[Pathfinder76]

Group 1&2



Group 3&4



The only difference is the bullet and powder charge. Sometimes you need to change something, but thinking someone else's load will be nirvana in your rifle is a fools errand.

[tchardy1972]

Originally Posted by markg

Some great ideas so far thanks guys.

Next reloading session will be with a new can of powder I recently purchased. I will also be replacing my battery in my magneto speed. I will also try some neck sized brass and compare it to the full length. Maybe the tension was to high from the one die. If that doesn't work then Dick might be right and it's a function of the cartridge. Thanks again guys for the great solutions. It was just what I was looking for. Sometimes when your in the situation you can't see the trees for the Forrest.

I'll post new results when I,am finished testing the new loads.

New can means a new lot. A new lot means you will most likely need to adjust your load anyway. It's very possible that your load is just not quite in tune. Personally, I would try h-1000. H-4350 leaves too much shake room in the case. I prefer a full case that's not compressed. That's just me though.

[rem338win]

Chrony isn't working right and you need to try a different primer. From experience this can greatly affect your ES.

That said I'm a big fan of H4350 and RL19 in the .243. My Amax load is consistent with RL19, BR2s and full length sizing. I'm running an AI though.

[tchardy1972]

Also. Don't pay too much attention to the chrony reading. They all have an allowable error of + or - 1% or so which is + or - 30 fps at 3000 fps. If the group prints flat on target at 300 yards +, you don't need a cheap computer to tell you all is good.

[xring_assassin]

Originally Posted by Dick284

Could be that your seeing the results of pressure spikes which the .243Win and heavy bullets are famous for.

Much as it pains me to agree with this clown - I think he's right on the money here. Lol

[58thecat]

Originally Posted by xring_assassin

Much as it pains me to agree with this clown - I think he's right on the money here. Lol

Or your scale is wonky and your out on powder weight...ahhh reloading

[markg]

Originally Posted by 58thecat

Or your scale is wonky and your out on powder weight...ahhh reloading

It cant be that. I calibrate the chargemaster before reloading and I zero my beam scale before reloading. I dont think both could be off that much ( i double check each load). They are usually identical but sometimes the chargemaster will get off as much as 1/10 and then i just have it try again. I think it happens when i put the pan back on to quickly and it doesnt zero correctly.

[Pathfinder76]

Originally Posted by xring_assassin

Much as it pains me to agree with this clown - I think he's right on the money here. Lol

A pressure spike causing a 753 fps jump in velocity? Not remotely likely.

[aardvaark]

Somebody mentioned above to only change one variable at a time. I double and triple that.

If you do 2 or 3 changes all at once, you'll never know which one it was that is the problem.

Start with the simple thing - like change the battery. Better yet get your load worked up without the chrony. Work it up to where it shoots the best with no pressure signs and then chrony it so you can work out your ballistics chart. Doesn't matter what the rest of the loads fly at cuz you're not going to use them anyway.

[markg]

So the 42 grs has 3 together and two outliars

the 43 grs has 2 together and another 2 together with 1 outlair.