Wow- How do I ever get a good group when Changing powders?

[Triple Deuce]

If you guys can think back to when you loaded your first POUND of powder, you may get on the same page I'm at right now.
I just went Through my first pound of Hogdens Benchmark powder. I developed loads that worked very good for 50 gr. Matchking bullets and then 50 gr. Nosler ballistic tip. I never had to change my scope. Things went rather logically when determining the powder charge. I'm shooting just below 1 MOA and sometimes .5.
Now the trouble begins. I changed to Hogdens 322 powder and was trying to develop a load with some 50 grain Hornady V-max and things went south. I am now at least 2 inches LEFT from where I was with the Benchmark powder. I shoot some of the Nosler loads (previously loaded w/Benchmark) and they are right on. So I don't thing the scope changed. I don't understand the change in horizontal POI? I can get them to group OK but way left (2 inches) at 100 yards.
Any input to help me understand what's happening ??

 

[mao0720]

When you change any component you can expect a change in POI. Most likely your barrel harmonics changed with the different burn rate of the new powder, so you are getting a different POI. Out of curiosity why did you change from benchmark to 322 right after you worked up loads for benchmark?

 

[lrgoodger]

Read this thread.

http://forum.accurateshooter.com/index.php?topic=3737679.msg35817711#msg35817711

 

[Triple Deuce]

MOA - I changed powders from Benchmark to 322 because I didn't know which one would work the best. Many triple deuce shooters claimed 322 produced more championships than any other powder for this caliber. I am just getting into reloading and figured I would learn with the Benchmark powder and then use 322 once I figured out how to do things. I guess I was ignorant to the fact that the poi would be so different. I thought in my reasoning that all I had to do was match the fps by varying the amount of powder and the point of aim would be the same. But that just don't seem to be working because the horizontal difference is significant. Does the harmonics of the barrel cause a figure 8 motion ? Do I just pick on powder and develope loads and stick with that recipe??

 

[mao0720]

Yes, once you develop a load with a specific group of components, ie. powder, primer, bullet, brass, you should, stick with that load as best as possible. Not to say that you cant develop loads with other component ( I have 2 loads developed with 2 different powders for my FT/R rifle) but you must understand that handloading is like witchcraft, if you change one part of the recipe then the whole equation changes and you are essentially starting over from scratch.

So, by all means develop a new load with 322, and see if it shoots better than benchmark. But, understand that it is a totally different load than your benchmark load and therefore will have a different POI. Also you will need a different charge weight, and perhaps even a different seating depth and primer type to get it shooting well.

Like I said, change one part of the recipe and you are cooking up a whole new brew.

 

[CPorter]

With factory hammer forged barrels a figure eight pattern isn't uncommon. When doing ladder tests on these I prefer three rounds at each load. As I shoot the ladder I keep track of hit position on target and group size. I could see the groups shrink and swell as the as the pattern migrated from up left to low right and back again. There were two nodes, one with 5 or 6 loads and one with 3 or 4. I picked the larger node because I figured it would be less heat sensitive. I then fine tuned by adjusting seating depth.

When switching powders or bullets and sometimes primers will change the residue pattern in the barrel which changes POI, grouping, etc. You will need to clean or fire several fouling shots before it wil maintain poi & grouping.

 

[LHSmith]

Many triple deuce shooters claimed 322 produced more championships than any other powder for this caliber.

H322 as produced today is no where near the burn characteristics that is was 50 years ago when the .222 was THE Benchrest cartridge.

 

[CaptainMal]

Barrel timing. Simple.

The powder change made the bullet change time and pace in the barrel compared to the other load. It changed the vibration pattern and changed the point of impact

That could be but is not necessarily related to a "good group" or accuracy.

You changed barrel timing and impact point. Expected.

 

[Triple Deuce]

To All - This reloading stuff just got a whole lot more complicated. The fact that you are not just dealing with a vertical variation but a figure 8 pattern. I should have bought a lot more Benchrest powder and stuck with that only.
Thank You all of your input.

 

[Janson]

Don’t do what I did waste money and time and barrel life .once you find a load that works I would stick with it

 

[10XSHOOTER]

If it ain't broke, Don't try to fix it!

 

[jimmymac]

Zombie