I've been out of the competition game for about 9 years but decided to get active again by shooting my first F-class match (600 yd). I dusted off my space gun (5.56x45) and reloading equipment; bought a bipod and rear bag, chronograph, etc. What I didn't buy was any reloading components since I have a lot in storage.
Previously, shooting 600 yards I had a standard load of 25.0 gn of V550 & RWS primer behind a Sierra 80 gn #9390M bullet, loaded to 2.490" LOA. Which produced around 2720 fps with a really good SD of 7.
Going through what I had in storage, I decided to work up loads using Rem 7 1/2 primers. I worked up from 25.0 to 26.5 gn of N550 and was not exactly thrilled with the results. I did get 2800 fps at the high end with no signs of excess pressure but my SDs were all around or above 20. (This is probably the worst SD I've ever loaded.) 26.5 gn fills the case to the shoulder. All the cases were the same Winchester lot, carefully prepped; primer pockets, flash holes, neck turned, etc. All the components are at least 10 years old. The n550 is from '95. The primers are probably about the same age. They've all been stored in air-tight containers in an air-conditioned room and show no signs of deterioration.
I've gone ahead and loaded 65 rounds with the 26.5 gn load for this match because I don't have time to start over and try something different. I won't be surprised if I see a lot of vertical stringing.
When the dust settles I plan to go back and try a bunch of new loads using various powders and primers. I'd like to pick the brains of folks who have more experience with N550 than I. Here are some theories:
1. The primers are old. Get new primers.
2. Remington 7 1/2 primers aren't suitable with N550. Use a different primer.
3. The powder is old. Fertilize the garden with it and buy new.
4. Your new CED M2 chronograph is giving you bad readings. Find out what's wrong and fix it.
5. Something else.
Of these I mostly suspect #1 & #2. Anyone care to share any thoughts? Thanks!
Previously, shooting 600 yards I had a standard load of 25.0 gn of V550 & RWS primer behind a Sierra 80 gn #9390M bullet, loaded to 2.490" LOA. Which produced around 2720 fps with a really good SD of 7.
Going through what I had in storage, I decided to work up loads using Rem 7 1/2 primers. I worked up from 25.0 to 26.5 gn of N550 and was not exactly thrilled with the results. I did get 2800 fps at the high end with no signs of excess pressure but my SDs were all around or above 20. (This is probably the worst SD I've ever loaded.) 26.5 gn fills the case to the shoulder. All the cases were the same Winchester lot, carefully prepped; primer pockets, flash holes, neck turned, etc. All the components are at least 10 years old. The n550 is from '95. The primers are probably about the same age. They've all been stored in air-tight containers in an air-conditioned room and show no signs of deterioration.
I've gone ahead and loaded 65 rounds with the 26.5 gn load for this match because I don't have time to start over and try something different. I won't be surprised if I see a lot of vertical stringing.
When the dust settles I plan to go back and try a bunch of new loads using various powders and primers. I'd like to pick the brains of folks who have more experience with N550 than I. Here are some theories:
1. The primers are old. Get new primers.
2. Remington 7 1/2 primers aren't suitable with N550. Use a different primer.
3. The powder is old. Fertilize the garden with it and buy new.
4. Your new CED M2 chronograph is giving you bad readings. Find out what's wrong and fix it.
5. Something else.
Of these I mostly suspect #1 & #2. Anyone care to share any thoughts? Thanks!