Although I've been reloading for 6-7 years now and for 9 different calibers I never really understood how much difference there is between brands in primers. Today I went to stock up on large rifle mag primers and they only had winchester and although what I've used thus-far has been federal I bought a couple packs of the winchester to give them a try.
Can you folks shed some light on if there really is a difference in primer brands and your loads?

There is a difference in primers but from what I can tell ( I'm certainly not the Great Guru of Handloading!!)it's only an issue if you are running max loads or if your results (FPS, SD) are not what you want or expect, especially if you are a Benchrest / Long Range shooter. If you have a favorite load that isn't near the limit of pressure and common sense - you can probably exchange one mfc primer for another.

I wish I was a good enough shot to care if my primer was Winchester vs. Federal!!!

I suggest reading "what causes this?" on page four of this same forum. You will get some insight into Winchester primers plus a few others.

I'm with ChasR on this. The difference is so minute that it really doesn't matter unless you are loading to shoot in competition.

Sometimes yes other times no, I've nver seen fed. match or cci benchrest make thing worse. IME win. rifle seem to give higher vel. and rem pistol does the same from what I've used

Some powders like a bit hotter primer than others.

Lately I've been playing with CFE223 in an accurate 308. Lapua brass, Nosler match bullets, consistent low runout, the usual stuff. I started with CCI 200 primers, and worked with different charges to find the sweet spot. Five shot groups were hanging right at .7 MOA. Swapped in the WLR, and voila, half MOA groups.

WLR are fine as long as you don't get primer leakage with them. Had two more this week when firing from my 06. I used nothing but winchester primers now thinking of switching over. Tired of my bolt faces getting chewed up!

I had always been told that Winchester primers tend to burn hotter so they are more reliable in colder weather and used for harder to burn powders? Never had an issue with them is this regard. Buddy used the WLR in his 7 rem mag for a couple of seasons until he switched over to the "magnum" primers.

If one likes "hot" loads cci have the hardest cup and fed the softest. If one has a weak fireing pin spring use reverse thinking

Not a diss, but I have actually had loads with both large and small fed match made it worse. Lost velocity and accuracy. Powder was 8208 XBR. The other is my Swift, didn't work too well with either AA2700 or H-380. No problems with the BR2 and BR4.
As far as hunting loads I have always used WLR for 06 class rounds using slower powders.

I have heard and experienced myself in a couple of cases recently where winchester WLR primers fit looser in primer pockets than CCI or Federals. Dont know if it was a fluke or a trend, but I've been steering clear for that reason alone.

I have seen slightly lower velocities with fed match primers (never used and std. fed. primers)but never seen groups open up , but don't doubt that it could happen . I have't used any of the powders you listed with fed. match primers either .

Have loaded my rifle loads nearly exclusively with Win since that's mostly what has been available for the last 2-3 years. I found an older box (4 years old) of CCI 200's and somehow loaded a couple in a group of 243 rounds.
Shooting 10-shot groups for SD I noticed that the loads with the CCI's were about 75-90 fps faster. Point of impact wasn't changed though. Skewed my numbers on my SD so I'll just have to 'force' myself to load some more and go back to the range again.

In my experience, winchesters seat the loosest.

Federals usually win the accuracy game, but have had 2-3 rifles where they were the worst shooting primer.

CCI BR's always seat tight, and can get you a few more loadings if pushing the upper limits.

CCI BR's have treated me good, but my general rule is to start with federal, either match or standard, and check for accuracy. Then start playing with other brands.

Primers matter.

I had groups go from 1" to 3" from just changing primers.

I've also had point of impact move a full foot at 100 yards while maintaining excellent accuracy from just changing primers.

As for velocity, sometimes the difference is minimal, other times it's closer to 100 FPS.

The only way to know for sure is to ask your rifle.

Yep. The rifle will let you know what is working..

I use CCI Magnum primers for everything. Its simple and every rifle I own shoots under an inch so I really don't see what all the fuss is about.

Shod

I have found primers to make a big difference. Check out this link:

http://www.6mmbr.com/PrimerPix.html

I learned that primers really do matter when using a rifle of sufficient accuracy to prove this, but most hunting rifles will only generate lesser observations.

25-75fps variance is common.
accuracy, grouping either larger or smaller is common,
group POI is less common, but can be noted on occasion.

Check this out. The only difference in the loads is the primer. Some rilfes prefer Winchester. Some CCI and others Federal. Primers can and do make a difference.

Savage 26” heavy barrel .223

Here are some loads with Varget and JLK 65 grain VLD's and different primers.

The powder charge of 27.5 grains usually produced velocities in the low 3200s in this 26" heavy barrel Savage .223. The primers used are as follows: Federal 205 and 205 M, Remington 7 1/2 Bench Rests, CCI BR 4 and 450 magnum and Winchester WSR. All groups used five shots at 100 yards.

Federal's 205 made three groups. They measured .519" @ 3220 fps, .962" @ 3224 and 1.216" @ 3210". The 1.216" group had a couple of fliers. They averaged .899" @ 3218 fps.

The 205 M from Federal is a match primer. There are records for four groups. They show groups of .709" @ 3224 fps, .726" @ 3224 fps, .644" @ 3224 fps, .757" @ 3227 fps. Their four group average was .709" @ 3225 fps. This primer produced the most consistent velocities that I have seen in any firearm.
Consistent velocities did not translate into the best accuracy, though.

The four Remington 7 1/2 Bench Rest primer's groups measured .744" @ 3211 fps, .682" @ 3211 fps, .676" @ 3224 fps and .682" 3223 fps and averaged .696" @ 3217 fps.

Winchester's WSR primers worked as follows: .582" @ 3220 fps, .399" @ 3249 fps, .830" @ 3219 fps and .812" @ 3219 fps. The average for WSR is .656" @ 3227 fps. All of the WSR primers were pierced by the firing pin.

The next primer is the CCI 450 magnum. It produced .684" @ 3200 fps, .546" @ 3207 fps, .711" @ 3234 fps, .544" @ 3219 fps, .806" @ 3191 fps and .525" @ 3218 fps. The average for the magnum primer was .636" @ 3211 fps.

The last one tried was another bench rest primer. It is the BR 4. We saved the best for last. The groups measured .492" @ 3245 fps, .477" @ 3250 fps, .441" @ 3245 fps, .452" @ 3232 and .460" @ 3229 fps. Its phenomenal five groups average is .464" @ 3240 fps. It also produced the highest velocities.

With the same rifle using the same powder firing the same bullets groups with the "best" primer are half the size of the worst groups.

When I tried the 52 grain JLK's I tried only two primers: the Remington match and the standard CCI. After eight groups of five shots with each primer the standard primer's groups were about 3/16" smaller on the average than the match primers.

Not my information. CCI and Federal are two brands that have primer cups too soft to be recommended for use in military designed rifles like the M1A. Winchester, CCI's #34, and Tula primers are recommended for those rifles with floating firing pins.
I've never seen POI affected by changing primers. But I have seen groups shrink when using hotter primers like Winchester.
The only primer leakage I've experienced has been from very hot loads. E

handwerk,
I went through the same quandary and I ran some informal tests of brands and standard vs magnum primers. My Speer manual often indicates magnum primers on some standard caliber recipes. I do not just "wing it" I'm interested in a "good" hunting load not maximum velocity or energy per se. What I "learned" was of little value for my use. Velocity, POI, and group size varied but not of much consequence. Sometimes scope adjustment would be fruitless at normal hunting range of <300 yards. Bench rest shooters or varmint shooters might be much more concerned about variations of tiny fractions of an inch at 100 yards. Your usage and what your rifles prefer is what matters to you. These days of uncertain availability in reloading components require I be somewhat flexible as to my components and "pet loads" as my preferred ingredients may be "out of stock". I don't think this is going to improve much in the near future if ever so having ONE recipe for a given rifle/caliber may cause more frustration than having an open mind and a variety of ingredients on hand so that your primer/case/powder/bullet can be massaged into an acceptable finished product. While I understand this mentality adds to the problem, I don't horde components but I try to keep a modest inventory so I have what I need to shoot anything from p pups to big game to punching paper. jm2cts