How much difference do primers make?

When I started my handloading career a whole year ago, I read somewhere that Federal 210M primers tend to be very consistent, so I bought about 500 and have pretty used only those. Most my experimentation has been with bullets and powders in various charges, seating depth a little. But I've heard about people changing primers and doing well with a particular load.

I've always just considered primers to be simply an ignition system, not that important beyond just needing consistency. More to it than that?

Yes, I did a test on here a while back, I will see if I can find it. Each primer changed the group size quite a bit.

https://onyourownadventures.com/hunttalk/showthread.php?281663-So-how-about-primers&highlight=Primer

They've made a difference for me, especially with magnum primers and ramshot powders.

Addicting said:

Yes, I did a test on here a while back, I will see if I can find it. Each primer changed the group size quite a bit.

https://onyourownadventures.com/hunttalk/showthread.php?281663-So-how-about-primers&highlight=Primer

Click to expand...

Looks like I was the one That actually started that thread. Wow. I forgot about that.

They affect more then you think. Group size, velocity, extream spread, standard deviation, pressure, all from that tiny little "go button". I have found best success with CCI BR-2 primers. Those are my go to for accuracy and long range target shooting. I use winchesters for everything else. They are cheaper and easier to find

Depends on a lot of factors. Certain powders are harder to ignite, and that can be compounded by the load itself. In those cases a poor primer choice can cause more velocity deviation than that primer would in a different load. Sometimes a different primer might take you off your accuracy node and result in poor groups but an adjustment in powder charge would get you right back to shooting great. CCI and Federal have pretty hard cups and you can shoot hot loads without pressure signs, and switching to a softer cup like a Winchester could result in a pierced primer from a load you didn’t know was hot. Most competitive shooters shoot “Russian” primers, Federal Gold Metals, CCI Benchrest or CCI Magnums. By the same token, a statistical analysis of the shot strings they usually analyzed will show that there isn’t enough information there to give a high confidence interval. You can shoot sub MOA with just about any primer. Ball powders are difficult to ignite and usually do best in loads that are hot, mostly full, and use a medium to heavy bullet for the caliber. Magnum primers help with ball powders. CCI Benchrest primers have some of the magnum qualities(long burn time). Hard cups like CCI and Federal help with high pressure loads. S&B primers are often overlooked and a available during shortages at good prices and have given me some of my lowest, single digit, extreme spreads(three 5-shot strings isn’t conclusive however). The improvement in extreme spread offered by a consistent primer is not evident at inside of normal ranges or from guns that won’t shoot under .5 MOA at close range. The only time a primer change is gonna take you from an MOA to a half MOA is when you were on a scatter node and another primer just happened to get you off of it, or when you weren’t igniting your charge well.

Generally, I don’t think primer selection is something you should be too worried about. Yes swapping them can change your group, but if you shoot over a chrono, you’ll see why, and if you adjust your powder charge so that you’re shooting the same velocity with both primers, you’ll find the difference isn’t usually all that meaningful.

Spot on Bill

I haven't noticed much change in velocity, but have noticed a drastic change in group size by changing primers.

Planning to do some work with Ramshot Big Game in my 7-08. That's a ball powder. Would Fed 210M's be adequate?

Yes, 210 M's and CCI 200 have worked fine for me with Ramshot Big Game in 7mm-08. Let us know how the Ramshot Big Game works out for you. I have some initial thoughts. I'm curious to what this powder does in your rifle.

Brian in Montana said:

Planning to do some work with Ramshot Big Game in my 7-08. That's a ball powder. Would Fed 210M's be adequate?

Click to expand...

Lapua brass(new)
47.5 grains of Big Game
WLRM
140 grain Partitions
2.80" COAL
Gets me 2870fps in my Model Seven with a 20" barrel and excellent accuracy.

I also use WLRM in my 120 grain NBT with Varget load. The magnum primers really tightened up the group size and lowered my sd.
In my 7-08

Great...another variable that I have to play with