.204 Primers?

[MrMajestic]

My .20-.223AI is about a duplicate and I run the BR-4 with H4895/39 gr. BK's and RL17/55 gr. Berger. I use the 7 1/2 in larger capacity SR primer cases. I will be loyal to the 7 1/2's because when I couldn't get the others Big Green always had primers on the shelf! German Salazar did some testing of primers in a clear tube and the 7 1/2's looked like a blow torch! High brisance may be an understatement!

[SS427]

Considering the current cost of BR-4 primers, I would develop my load around the 7 1/2 primers. Unless you have a full custom benchrest 204 Ruger I really doubt you will see an accuracy difference.

The chart that Chickenthief posted has always been my guide for primers when it comes to cup thickness, but that chart is going on 20 years old. I have to wonder if the data on it is still valid.

[trotterlg]

The BR4's and 450's shoot to the same poi in my 17 Remington, and I really can't tell and difference in accuracy. Larry

[Pahoghunter]

Originally Posted by bridgeport

I'm running BR-4's on Nosler brass, 39gr Sierra blitz king, 26.5gr of H335, and an OAL of 2.265. This load is giving me moa or better out to 300 yards (10 shot groups) with 7 out of those 10 shots being .5 to .75 MOA out of a CZ-527 with a varmint weight barrel. The other bullet I am using is the 32gr Nosler e-tip lead free which is giving me .5 moa vertical, but wind stringing of about 1.5moa at 300 yards. I will be testing out to 400 yards with this load starting later this week to see what type of accuracy this load will maintain.

-B

That's really good accuracy, on the 39 Sierra, 2.265 is how far off of the lands? I'm having trouble getting accuracy out of my Savage .204. thanks Bob

[bridgeport]

Pahoghunter, I have not checked the distance off the lands, because in the CZ 527, the limiting factor is the magazine length. Instead of playing with seating depth, I have had to work with powder type and load volume. First I tried IMR 4895 at various load densities, finally settling on 28.5gr, (I went up to as high as 29gr in testing) however I was unhappy with the flier percentage. I decided to try the H335 as that gives decent velocity with lower load density, and finally settled on 26.5 gr as that was giving me the most consistent grouping over 10 shot strings. .204 is a real barrel heating cartridge so I shoot two shots and then allow for cooling before going on with two more etc. If I go with more than two or three shots, accuracy immediately begins to suffer. Also, on the advice of a board member here, I wipe every 20th shot for copper fouling, and that really helps keep the accuracy dialed. The 39 blitz king suffers badly from wind drift. I was out yesterday testing and the wind was switchy, my hold off at 300 yards, was 1.5moa to drop into zero. My vertical though was .75 moa except for the occasional high flier, which was 1 shot out of 10, and was almost always the 3rd shot of a string (I am learning to adjust for the rifles tendency to shoot high as it heat up) I have never posted a picture here, but I will try to get some pics up of my targets so you can dissect the groups and see what I'm talking about here.
Regards, B

[Pahoghunter]

Originally Posted by bridgeport

Pahoghunter, I have not checked the distance off the lands, because in the CZ 527, the limiting factor is the magazine length. Instead of playing with seating depth, I have had to work with powder type and load volume. First I tried IMR 4895 at various load densities, finally settling on 28.5gr, (I went up to as high as 29gr in testing) however I was unhappy with the flier percentage. I decided to try the H335 as that gives decent velocity with lower load density, and finally settled on 26.5 gr as that was giving me the most consistent grouping over 10 shot strings. .204 is a real barrel heating cartridge so I shoot two shots and then allow for cooling before going on with two more etc. If I go with more than two or three shots, accuracy immediately begins to suffer. Also, on the advice of a board member here, I wipe every 20th shot for copper fouling, and that really helps keep the accuracy dialed. The 39 blitz king suffers badly from wind drift. I was out yesterday testing and the wind was switchy, my hold off at 300 yards, was 1.5moa to drop into zero. My vertical though was .75 moa except for the occasional high flier, which was 1 shot out of 10, and was almost always the 3rd shot of a string (I am learning to adjust for the rifles tendency to shoot high as it heat up) I have never posted a picture here, but I will try to get some pics up of my targets so you can dissect the groups and see what I'm talking about here.
Regards, B

Pics aren't necessary, I tried different seating depths, after I fired 7 different groups at 100 yds. all were under .500, I picked to of those groups to work off of, the smallest group and the smallest vertical dispersion. With different powder charges 2 tenths of a grain from to min. to max. but this time I went to 200 yds. working off of the best group the results weren't that impressive, but working off of the best vertical dispersion group I was at .785. So now I have to try and get that group a little smaller.

[bridgeport]

Originally Posted by Pahoghunter

Pics aren't necessary, I tried different seating depths, after I fired 7 different groups at 100 yds. all were under .500, I picked to of those groups to work off of, the smallest group and the smallest vertical dispersion. With different powder charges 2 tenths of a grain from to min. to max. but this time I went to 200 yds. working off of the best group the results weren't that impressive, but working off of the best vertical dispersion group I was at .785. So now I have to try and get that group a little smaller.

I'm right there with you, at 100 yards I was getting superb grouping which carried over to 200yds with just a touch of wind stringing noticeable, but manageable. 300 yards has been a bit of a struggle and I am having to be patient and methodical, as well as remembering not to compare a 39gr SBK to something like a 107 match king out of my 6BR. As you have noted though, my vertical dispersion is good, and on a day when the wind is cooperating its all good. As usual, some of the improvement needs to take place between my ears as I meld mind with the realities of what the bullet will do, and learn to better compensate for it.