I finally figured out my accuracy problem with my Kimber 22-250.

I began with 55gr. Ballistic Tips, H-380, CCI BR-2 primers, and fresh Norma brass. I read that 39.5 grains of H-380 was the most accurate load per Nosler. I started 10% less like a good handloader should and found that to be the maximum load. It turns out that Norma brass weighs 10 grains more than Remington or Winchester brass. That accounts for the increase in pressure.

I also noticed that the accuracy, while MOA, was not spectacular. I would get three or four touching eachother, and a flier or two. The fliers corresponded to rounded primers, while the accurate shots corresponded to flattened primers.

I then sorted away the brass which caused the fliers, and repeated the process. I was expecting every single primer to be flat, but to my dismay some primers returned perfectly round. Thinking it was a ball powder/standard primer ignition issue, I switched to the CCI magnum primer. There was no change in either the group size or primer appearance. I couldn't blame it on the weather either, because the temperature was a nice even 70 degrees.

I then had a schizophrenic episode and one of the voices reminded me that 36 grains of H-380 barely reached the shoulder of my 22-250 case. I then loaded six rounds and fired two groups: one with the powder resting against the base of the bullet and with the powder resting against the flash-hole. The former droup was three times larger than the latter, and every single primer was rounded. Every primer in the latter group was flattened and all the bullets went through the same hole. I then continued to shoot through the same hole even with rounds having as much as .004" runout.

I am very proud of myself right now

I hope that some of the frustrated handloaders out there incorporate powder positioning into their bench technique to eliminate yet another variable in this wonderful hobby.

Ralph, that is a good post. You took a very sientific approach to your load development and was especially thoughtfull to think of the positioning of the powder.

I would have thought H 380 would have done better than that with the case that full, but this is just one of the reasons I do not use ball powders at all anymore.

I have found ball powders entirely too sensitive to such things as powder positioning in the case and ambient temperatures.

I have fired literally thousands of rounds of H335 loads in a 223 Remington but was always amazed that I would see a 100 to 150 fps difference on the chronograph from morning to afternoon on hot days. Sure had a good varmint load I thought, but performance varied. Groups would go from well under a half inch to one and a half inches depending on conditions. I switched to N 130 powder and am much happier.

When working up reduced loads for cast bullets in a 7-08 Remington I found ball powders to be extremely position sensitive. Positioning 748 powder next to the primer versus touching the bullet made a 200 fps difference on the chronograph. (And these loads were only going around 1800 fps to begin with.)

Again, very good load development.

Very nicely done. Thank you! roger

quote:

Originally posted by Ralph Hyrlik:
I then continued to shoot through the same hole even with rounds having as much as .004" runout.

I used to be a "run-out hound" until I found run-out up to .008-had no affect on group sizes under 300 yds. In fact, I know Camp Perry competitors that have up to .006 runout limit on their 600yd rounds. I used to list my rounds by the amount of run-out they had. I had the .001 through .003 labeled boxesand would redo any that got higher. Well, I made up a few batches of rounds one day with run-out between .001 and .008 and did a little experiment. I had my friend hand me 6 rounds of a perticluar run-out batch at a time, without knowing which batch I had I shot 300yd groups. We measured each group and found at the end of the firing, there was no significant difference between the group size of.001 and .008. Some of the higher run-out rounds group smaller than the rounds with less run-out.

quote:

I hope that some of the frustrated handloaders out there incorporate powder positioning into their bench technique to eliminate yet another variable in this wonderful hobby.

Tis better to load as much powder as possible into a case, unless it proves counter-productive accuracy wise.

This isn't to refute your results. However, I have not experienced the same drastic results with powder positioning when analyzing group size. About all of my most accurate rounds are filled only to the shoulder. Loading to the shoulder is considered well aqdequate.

Ralph's post was a good reason that I did not find the hallowed H 380 to be the most accurate powder in a 22/250. Don't get me wrong as I love it in other cartridges, just not the 22/250. Regardless if JB Hodgdon named the powder and load for the 22/250.
I just found other powders to work so much better in the 22/250.

H 380 only seems to be accurate in smaller cases if the capacity is close to full, eliminating position sensitivity.

However with larger capacity cases, such as a 270, I have found that it is not position sensitive. I guess there is enough volume of powder, that it eliminates whatever it is that makes it position sensitive in smaller cases.

We are proud of you also Ralph.

Cheers and good shooting
seafire

Great post. Thanks!

Here's a helpful hint for the use of ANY powder...

Load to around 90% density...and you don't have to worry about powder position.

quote:

Originally posted by ricciardelli:
Here's a helpful hint for the use of ANY powder...

Load to around 90% density...and you don't have to worry about powder position.

Steve, our Guru friend:

That gets kind of hard if you are using faster powders. I have found better accuracy with the faster powders in my varmint caliber loads than I do the one's commonly used nowadays. Older load manuals seem to have faster powder data, but are deleting them in newer manuals.

Last IMR load sheet I saw had deleted the 4759, 4198, and 3031 load data from most of the calibers. I did not even pick up the free copy because it had deleted so much of what I used.

seems that they want us all to use 4350, 4831 and 7828 for everything. It makes the lawyers happy with the reason you mentioned above. It sells more powder... and I am sure they have half a dozen other reasons that benefit them more than us.

cheers
seafire

Good work!
That probably explains why my most accurate loads are almost always with powders that result in a slightly compressed load. Thanks.