Magnum vs. Standard Primers?

[chuckw2]

I have 1000 CCI 450 magnum small rifle primers that i need to shoot up.

How much would you back off the charge of powder to start with?

This is in a .204 with 28 grns of Varget, 39 grn SBK, I have used the WSR primers and the CCI 400 primers with this load with no signs of pressure.


Where would you start with a Varget charge and CCI 450 primers, I was thinking about dropping down 2 grains to 26 grains.

Is that enough??

Chuck

 

[NeilNE]

Sounds about right,back off 2 grs.

 

[bigwoodsman]

i have a 22-250 tikka t3x with a 22 inch barrel and thought of using a mag primer my scenario is using a Sierra 65 grain bullet in a 1:8 twist barrel i am using the starting load of 33.0 grains of imr 4064 by the Sierra book i get good round 5 shot groups but cant get any better then 3/4 at 100 yards tried bullet jump and neck sizing cases and it didnt help i am thinking the powder may not burning up enough in this length of barrel i don't have a chronograph to check velocities, am i thinking on the wrong side of logic on this matter

 

[Jeff Porter]

My experience is the 450 Magnum is more in reference to the cup thickness than any brisssilance difference. 450's give smaller ES and SD in my loads than 400s too.

similar to this result.

 

[Ruger15151]

Magnum primers don't necessarily create more pressure or velocity. I load Varget and 450s in my 308 FTR rifle. BR4 actually give more velocity but 450s give better SD/ES in my competition loads. Therefore, you don't have to back down on the powder just because you are loading with magnum primers.

If you are already close to pressure and you don't have a chrono to check the velocity change, you can drop .2-.3 grains to make yourself feel better but its probably not necessary.

 

[spudgun]

Last year when primers were very scarce I decided to try a test with different primers.

The thought was to find out if I ran out of my main primers how the other primers would effect my loads.

I had the following small rifle primers: CCI 41, CCI 400, CCI 450, Federal GM205M, Winchester WMSRL.

My load was: 40.6gr H4350, 105gr Hornady HPBT Match, Starline brass, 6mm CM.

Loaded up 7 rounds each primer and went to the 1000 yd range. The range has electronic targets that show the FPS at the target.

After I shot the rounds I recorded the FPS and did a average. After all rounds were fired and recorded I noticed only 31 FPS difference between the different primers (High to low).

This low difference told me that I could sub out primers with out a big drop or gain in the velocities.

SHOT		#1	#2	#3	#4	#5	#6	#7	AVG	SD	GRP"
WINCHESTER		1365.0	1340.0	1324.0	1328.0	1336.0	1338.0	1294.0	1332.1	15.9	19.5
CCI 450 MAG		1342.0	1317.0	1323.0	1343.0	1359.0	1311.0	1312.0	1329.6	18.5	18.5
CCI 400		1331.0	1320.0	1328.0	1319.0	1346.0	1345.0	1320.0	1329.9	9.6	11.3
CCI #41		1327.0	1351.0	1344.0	1305.0	1368.0	1339.0	0.0	1339.1	22.8	17.7
FED 205M		1296.0	1285.0	1346.0	1311.0	1329.0	1280.0	0.0	1307.8	24.6	14.3

 

[6.5 forever]

Magnum primers don't necessarily create more pressure or velocity. I load Varget and 450s in my 308 FTR rifle. BR4 actually give more velocity but 450s give better SD/ES in my competition loads. Therefore, you don't have to back down on the powder just because you are loading with magnum primers.

If you are already close to pressure and you don't have a chrono to check the velocity change, you can drop .2-.3 grains to make yourself feel better but its probably not necessary.

This is my exact experience.

 

[Loudenboomer]

Interesting. Makes me wonder if the variation would be greater in a larger powder column and slower powders. I was thinking .338 Lapua Large rifle vs LR magnum.

 

[DLT]

I moved to magnums. They would pop up here and there where I’m at. So I use them and use normal load data.

 

[Ernest T]

My experience is the 450 Magnum is more in reference to the cup thickness than any brisssilance difference. 450's give smaller ES and SD in my loads than 400s too.

similar to this result.

That's my experience as well, not much more velocity, but better consistency.

 

[bigwoodsman]

My experience is the 450 Magnum is more in reference to the cup thickness than any brisssilance difference. 450's give smaller ES and SD in my loads than 400s too.

similar to this result.

Thank you Sir that Video certainly helped me out greatly