450's vs 7 1/2's in 6BR

[Rflshootr]

Has anyone done any chrono testing between 450 & 7 1/2 primers? I'd be interested in velocity differences with the same load and SD differences.

 

[Loggins J]

I know 450 faster then fed 205 never tried 7 1\2 I would go with what shot the best

 

[Rtheurer]

 

[Rflshootr]

View attachment 998087

So if I'm interpreting that correctly, the 7 1/2 gave a difference in pressure of 974psi and the 450's were higher pressure and gave a difference of 2437psi for the 2 shots of each. The 450 generated 1510psi more pressure in this instance. Correct?

 

[Rtheurer]

Keep in Mind:
Two primers, One lot number of primers, only ten shots.... Does not make one bit of conclusive data.
Might be a trend building after more testing.

However... On Higher end pressure I have found a trend for the 7 1/2's and 450's to be really close to each other. I Cant say that this will be different in a Bolt action rifle in a separate Caliber.

Probably should not even posted this..

Russel

 

[Rflshootr]

No Russel. I'm glad you did! Information is always good regardless of how conclusive it may or may not be. It's recorded data that may be expanded upon in the future. Thank you. Now I do have another question....was the same piece of brass used for each firing? Or the same 2 pieces of brass? What really surprises me is the numbers from the 205.
I wish I had the equipment to do this kind of testing.....and a tunnel to shoot in.....and unlimited reloading supplies....and well.....you get my drift.

 

[Rtheurer]

No Sir. 10 Separate pieces of brass.

 

[Rflshootr]

Thanks again. All data is useful.

 

[rminut]

Russ, interesting data points that match some of German Salazar's primer testing. His data showed that Rem7.5 posted very good deviation numbers and also the Wolf SRM had good numbers. The other interesting point in his data was that the Rem7.5 was considered the hottest SR primer and the Wolf very mild, but they posted similarly low ES/SD numbers. I believe he did his testing with 6br and Oehler 43.

 

[Desert Fox]

I used 7-1/2 exclusively for my 6.5-47 Lapua. Very consistent and low SD. It is a larger case compared to a BR therefore I assume it will perform just as well.

 

[Eric Leonard]

I was gonna do this test with my Farley 6BR but whoever originally smithed this rifle has it to where it will not light the CCI450 or the Tula 5.56 Magnum primers,,it sure shoots well with WW WSR and Fed 205s though,,

I will do it with my Stiller BRDX next time I have it out though,,it shoots its best with the Tula Magnums and the 450s are pretty much interchangeable ,,,I have some 7 1/2s I use in my AR15 loads but havent tried them in the BRDX.

I have proven to myself without doubt that my 6.5x47 shoots best and has its best ES using H4350 and the WSR primer,,I shot a 10 shot string with it over the magnetospeed that had 6 duplicates and the other 4 were less than 5 fps off,,the SD it showed was 1..
that was with the 130 VLD and 42.2 H4350 and the WSR

 

[stacy]

WELL IN MY 6BR WITH 105 VLD HUNTING AND N-540 WITH 450'S DOES VERY WELL THE 7-1/2 IS NO COMPARISON WITH MY LOAD HAND DOWN 450'S SERVE ME BETTER