Primer dofferences

[Green Bullet]

I started reloading my 7 mag with Remington magnum primers.  I got my hands on some federal match grade and I believe my POI is lower out at long range 600+ yds.  
 

what are your experiences on how primers impact POI?  I’m using RL22. 

[HuntHarder]

Did you chrono your new load? 

[Green Bullet]

No not yet.   That will be a next step. 

[Crazymonkey]

Primers will run at different  rates just as powder will .I don't  have enough  experience  with the different  brands but if you can get Lance to chime in I'm sure he's done some testing  on large rifle vs mag and also a few different  brands and what the changes to velocity might be.

[10Turkeys]

Couple of variables. You didn't say if the Federal primers were 210M or 215M. If you went from a magnum primer down to a standard rifle primer then yes your poi is going to change. I'm guessing that your running about 60-70 grains of powder in that 7 mag. I wouldn't use anything but a magnum primer myself. You said that your using RL-22, that's all I use in my .270 and I've never had any problems with it as far as it being temp sensitive, but if you zeroed your rifle in July with the Rem primers and loaded up some with the Federal in October that might be your poi shift also. How far off was the poi shift between primers?

[Green Bullet]

Both were magnum primers so the delta is really the brand itself.   I was shooting steel pretty far but my guess is I was 1 MOA lower than my loads with the magnum Remingtons.   

[10Turkeys]

The chrono will give you an answer.

[PRDATR]

It would be interesting to see the fps difference. I only ever used one brand of primers when I loaded for 7Mag on either the Barnes 120X Bullets or others like 140PMC, 160 Partitions or 168HPBT Match Sierras. The only powders I used were RL19 or RL22. I did try some Thunderbird Cartridge maybe the 8208, still have some of that.

Sweet spot was usually between 69 and 71 grains.

[1uglydude]

Contrary to what was said above, RL22 is known as one of the *most* temp sensitive powders.  If you zeroed in the summer and you're shooting now, you could have lost quite a bit of velocity.

Here's some discussion with a chart showing some data points: https://www.thehighroad.org/index.php?threads/reloder-22-temperature-sensitivity.890322/

[PRDATR]

49 minutes ago, 1uglydude said:

Contrary to what was said above, RL22 is known as one of the *most* temp sensitive powders.  If you zeroed in the summer and you're shooting now, you could have lost quite a bit of velocity.

Here's some discussion with a chart showing some data points: https://www.thehighroad.org/index.php?threads/reloder-22-temperature-sensitivity.890322/

I always worked up my loads in the late fall or winter to simulate the temps I would be hunting in. The only animal I shot that was not below 50 degrees was a bear on September 12, 2000 up in South 23 in the early morning @ about 200 yards. I did shoot a Caribou on about September 10th about five years earlier east of Nome and it was maybe 50dgF @ 75 yards. Both with 120gr X Bullets.

[Green Bullet]

2 hours ago, PRDATR said:

I always worked up my loads in the late fall or winter to simulate the temps I would be hunting in. The only animal I shot that was not below 50 degrees was a bear on September 12, 2000 up in South 23 in the early morning @ about 200 yards. I did shoot a Caribou on about September 10th about five years earlier east of Nome and it was maybe 50dgF @ 75 yards. Both with 120gr X Bullets.

I appreciate the data but I don’t think I’m dealing with a temp issue.  Never been an issue in the past (not detectable anyway). 

[Cambow]

I second the chrono… 

[1uglydude]

11 hours ago, Green Bullet said:

I appreciate the data but I don’t think I’m dealing with a temp issue.  Never been an issue in the past (not detectable anyway). 

I ran the numbers for my 7mm mag load.  If I were to lose 75 fps, that would show up as about 3.5" lower at 600 yards.  How much lower are you hitting?

[MMACFIVE]

23 hours ago, 10Turkeys said:

The chrono will give you an answer.

 

23 hours ago, Green Bullet said:

Both were magnum primers so the delta is really the brand itself.   I was shooting steel pretty far but my guess is I was 1 MOA lower than my loads with the magnum Remingtons.   

It would really surprise me if primers caused a 1moa shift. 
 

load both and compare. 
 

any chance you switched powder lots?

[L Cazador]

On 10/31/2022 at 2:57 PM, 10Turkeys said:

Couple of variables. You didn't say if the Federal primers were 210M or 215M. If you went from a magnum primer down to a standard rifle primer then yes your poi is going to change. I'm guessing that your running about 60-70 grains of powder in that 7 mag. I wouldn't use anything but a magnum primer myself. You said that your using RL-22, that's all I use in my .270 and I've never had any problems with it as far as it being temp sensitive, but if you zeroed your rifle in July with the Rem primers and loaded up some with the Federal in October that might be your poi shift also. How far off was the poi shift between primers?

Here you go perfect what Ten Turks says!!  Use Mag primers over 55 grains of powder. I've been doing this for 50 years of reloading thanks to my mentor! POI, goup size, are dependent on temp, humidity, elevation, and reloading techniques. Never work up loads until your brass has been fireformed to your chamber and never work up a load where there will be more than 20 degrees plus or minus of that temperature you encountered during load work process. For competition I either load at the range or work loads two-three days before! Ammo that you load this year may not be good for next years hunt. Factory ammo? Sure it's good forever! You weren't expecting good accuracy to go with that statement? it would be an oxymoron!! LOL!!