Just looking to get some info on one aspect of reloading that I have overlooked (in my so far brief experience in reloading), the importance of primers. How do they effect accuracy and performance? I have only used CCI Benchrest primers so far for my .243 and have had decent results and am now wondering if I should try others to improve the performance of my loads? What primers are popular?

Thanks

Lazo

Only your rifle will tell. Of my 2 .300 Win Mags, the Rem 700 Sendero is indifferent whether I use CCI 250 or WLRM, while the Blaser R93 insists on CCI 250.

Some powders like the H450( Ball Powders) need a hot mag. primer. I use the cci br2 primer in my 243 win. w/ IMR 4350 & 4831 , shoots very well, no need to change. In the reloading manuals, if the data calls for a mag. or standard, best go with that. When changing brands of primer always lower powder charge and start working up a load from scratch. A mag prime may make pressures rise, again check reloading manuals.

The last step for me in any load development is to try various primers with a given load. Contrary to some articles I've read reporting much higher pressures with some primer swaps, I've never seen more than a few FPS difference in doing so. Also, about 75% of the time, changes in primers don't affect accuracy significantly. The balance of the time can be real significant.

Over the almost 50 years I've reloaded I've gravitated to Federal primers mostly, and that is where I start my load development. They are good primers and usually remain the primer for most loads by default. When I try others they aren't any better, and sometimes a bit worse. However, I had one rifle which shot over 2" groups with everything I tried, including most primers. The minute I swapped to Remington 9 1/2M's the loads shrunk dramatically by almost 2". It's the only rifle and cartridge that shoots those, but it mattered.

Primers can and do make a big difference some of the time. I normally try about 7 different primers in any load development and many times there is significant difference. It's worth keeping a variety.

I used to consider them not such a big deal, but have been re-evaluating that lately. A good example is my 350 Rigby, I'd been using CCI 250's and getting fairly good accuracy, but then decided to try Federal 210's (I know, it was also going from magnums to std primers) Same exact load and the group was 1/2 the size with the Federals. A few years back I was getting mediocre groups in a 308 and switched from CCI 200's to Federal 210's, and the groups also noteably tightened up.

I've always just used CCI primers... so all I know about the topic is from some tests that were posted on one of the boards.

According to the test, primers make very little difference in muzzle velocity, but they do make very significant differences in peak pressure.

In 30-06 loads, 53 grains A2700, 168 grain MatchKing, the 210 turned in 57,800 PSI, at 2778 fps, while the 200 turned in 52,500 PSI at 2708 fps.

An important item missing from the chart is number of cartridges fired in each configuration. Random measurement system error is significant, and it is hard to tell how much of the variation is primer and how much is measurement system. If we knew how many cartridges were fired, we'd know more about how trustworthy the numbers are.

Keep in mind that a fed 210 is thought to be actually hotter than a 250 cci. You gotta wonder why some are called "mag" and others arent'. If I remember right the win mag is considered hottest followed by the 215 fed and then right after the 215 fed is the 210 fed. There seem to be alot of "successful" magnum loads using the 210 fed cause in reality it pretty much is a magnum primer in relation to others. Just regergatiting info I've read in several places. Think I'll go take a tums!!