Primers can make a difference.

[ARlife4me]

I guess I'm in for a big surprise on anything other than cci 200 and 250's that I've used for close to 40 years in 270win and 264wm. Those were the only rifle cartridges I've loaded till 8 years ago. Now having 10 more cartridges that use a combo of large and large magnums and capacities from 50-105gr. These last 5 years are the worst times to do loaf development with that many cartridges in multiple guns with multiple bullet weights. Hopefully there's a quick finding! I'm awaiting the new Caldwell velocaradar as it would probably be smart to have a chrono before starting.

 

[Old Rooster]

Mother nature gave us another round of winter here in Montana so I can't get to the range but soon I will do my own tests.Not that I don't believe others tests but my own,on my paper targets will help me decide for my rifles.Plus we have extreme cold here at times so IDK.
MagnumMania has mentioned this before but I'm a little slow.

 

[dgp3006]

Tag

 

[980yds]

Sorry I was not clear. The only thing I changed was the primer. Even the brass was the same. First shot contained 91 grains and each subsequent shot contained one more grain.

With the large rifle primer there were no stiff bolt lift like with the magnum primers.

The yardage change too, correct? The first group was shot at 200 yds and second was at 100 yds. Why not do both groups at the same distance?

 

[Will.284]

I've been toying with the idea of using large rifle primers in my 7 prc's just for s&g's . It's been 3 weeks since rotator cuff surgery and less than a week since knee surgery so mabye in another week. Probably load some today

 

[xsn10s]

LOL ok so change the powder weight for each shot. And then for the second group change the distance, powder charge for each shot, and primer. LOL good luck.

 

[Will.284]

LOL ok so change the powder weight for each shot. And then for the second group change the distance, powder charge for each shot, and primer. LOL good luck.

Ummm why change all those variables. I was gonna change just the primers from lrmbr federal to lr federal

 

[PApa Black]

View attachment 547648View attachment 547649
I used the same brass for both groups. They were all full length resized. The first group was shot at 200 yards and the second group was shot at 100 yards.

They CAN make a huge difference!

 

[paul scrobohaci]

It's a simple fact that there really is no NEED for a magnum primer. I often use a standard primer even in my wildcats on the 416 Rigby Improved case where loads run 120+ grains, never have issues until a ball powder comes into the mix, which usually isn't quite compressed at all and the primer blast blows through the powder column, a magnum primer provides more pressure which compresses the powder and stops it blowing through it. It is visible on the pressure trace as a rise then dip in start pressure using a standard primer, it goes away when a magnum is used.
I often switch between the 2 in standard cartridges too.

Cheers.

I'd like to agree with you as I find using BR2 CCI (non-magnum) primers for my 300 win-mag yields better (lower) MV ES without any issues.

However, using same (BR2...) on my 338 LM causes over 30% misfires. When I open up misfired cartridges, the powder looks singed, but intact.

The powder is the same in both cases: VN565. The loads are: 75.2 gr for 300 win-mag and 84.2 gr for 338 LM, and the only other difference is the case size/shape. The 300 win-mag bullet is a 168gr TTSX and the 338 LM bullet is a 250gr scenar.

Care to comment ?

 

[xsn10s]

Ummm why change all those variables. I was gonna change just the primers from lrmbr federal to lr federal

That's my point, there is no reason to change all those variables at the same time. It's a skewed use of the Satterlee Method at the wrong distance.

 

[xsn10s]

Even if you were looking for max pressures this test doesn't fit. He had stiff bolt lift only to continue increasing the charge to get another stiff bolt lift.

 

[Dloh2o1]

I've been toying with the idea of using large rifle primers in my 7 prc's just for s&g's . It's been 3 weeks since rotator cuff surgery and less than a week since knee surgery so mabye in another week. Probably load some today

I think I'd give it a few more weeks if its your shooting shoulder

 

[Justice1327]

Load up one round of each using a regular primer on new Brass, remove your ejector plunger , go up in .5 grain increments and until you get to pressure signs. Then back off one grain and load up 3 to 5 rounds at that charge weight and shoot for group at 100 yards. Then do the exact same process at the exact same distance when you switch primers. As you are doing take note of velocity at each increment of powder charge increase.

 

[FireFlyFishing]

I guess I'm dense. What did the OPs test results yield with many different variables and a coarse ladder?

Inquiring minds want to know.

For those of you using LR primers on mag cartridges…cool. I won't use them on large charge cartridges as I live where it's cold. Sometimes hunting season in MT can be way below zero. I'd prefer a consistent bang in those temps.