Related Articles

Powder Temperature Sensitivity: The Hidden Factor Affecting Your Long-Range Accuracy

March 8, 2025

Rifle Load Development: How To Find The Best Powder & Load For Accuracy

March 1, 2025

Best Rifle Powder – What The Pros Use

February 7, 2025

When it comes to long-range shooting, consistency is king – and rifle primers can play a critical role in achieving it. A primer’s job is to ignite the powder charge, and how consistently it does that directly impacts muzzle velocity. Even slight variations in ignition can shift pressure curves, leading to velocity spreads that cause vertical dispersion downrange.

The best rifle primers are manufactured with tighter tolerances, uniform priming compound, consistent cup thickness, and reliable sensitivity. That level of quality delivers more consistent ignition from shot to shot, which translates into lower standard deviation (SD) and extreme spread (ES) in velocity.

For shooters stretching beyond 600 yards (especially 1,000+ yards), even small variations in velocity can cause significant vertical POI shifts. If your ammo has an SD of 15 fps, you could see 14-18 inches of vertical spread at 1,000 yards – unacceptable in precision rifle competitions. A quality primer helps minimize that variable, especially when paired with quality brass and consistent powder charges.

Bottom line: If you’re chasing extreme precision, don’t overlook the importance of selecting the best rifle primer. It’s a small component of your load, but it can have a big impact on consistency and downrange performance.

So, what is the best rifle primer? While everyone has an opinion, I surveyed the top 200 ranked shooters in the Precision Rifle Series (PRS) to see what rifle primer they were using in their match ammo. These guys represent the best of the best when it comes to long-range rifle shooting, so getting insight from them is far better than listening to some random guys arguing on a forum! 😉

Best Rifle Primer

Let’s dive into the data! Here is a look at the specific type of primers that the top 200 ranked marksmen in the PRS said they were running in their match ammo:

63% of these guys are using CCI #450 Small Rifle Magnum Primers! CCI 450 primers are by far the most popular choice. That doesn’t surprise me because CCI #450s have been the most popular option among pro shooters in the PRS for more than 10 years. They are known to be extremely consistent, and there may be another benefit to using magnum rifle primers that I’ll share later in this article.

CCI BR-4 Small Rifle Primers were tied for the 2nd most popular choice. It was used by 14% of these pros, and there were more top 10 shooters using it than any other primer – although that was only 1 more than the CCI #450 and the Federal 205M. The top 10 seemed fairly evenly split among the top 3.

Federal 205M Small Rifle Primers were also tied for the 2nd most popular choice among this group of elite competitors, with a couple of the guys in the top 10 running it as well.

91% of these shooters were using one of the primers above: CCI 450, CCI BR-4, or Federal 205M. Those are clearly some of the top-performing small rifle primers when it comes to long-range precision. If you are wondering what you should try in your match ammo, those are probably your best bets. But there are several other types of primers represented among this group, and here is the full list:

• CCI #450 Small Rifle Magnum Primers
• CCI BR-4 Small Rifle Primers
• Federal 205M Small Rifle Primers
• CCI #400 Small Rifle Primers
• Federal 205 Small Rifle Primers
• Federal 210M Large Rifle Primers
• Federal 210 Large Rifle Primers
• CCI BR-2 Large Rifle Primers
• CCI #41 Small Rifle Primers

What’s interesting is that only two primer brands are represented among all 200 shooters: CCI and Federal. A decade ago, CCI and Federal were still the most popular, but we also saw a few of the top shooters in the PRS using TulAmmo, Winchester, Wolf, and Remington primers (view the data from 2015). It’s interesting when you see consolidation like that over time, so I thought it was worth mentioning.

What Makes A Primer Benchrest or Match-Grade?

Many of these primers are marketed as “Benchrest” (BR) or “Match-Grade” (M) – but what does that even mean?!

I’ve heard all kinds of speculation on this over the years, but here is the definitive answer from Jeff Siewart, a ballistic engineer with 40 years of industry experience. This is an excerpt from his book Ammunition, Demystified:

“According to sources at various primer manufacturing operations, when you buy benchrest primers, what you’re spending your money on is a slightly larger quantity of primer mix, on average, than the standard primers and a slightly tighter tolerance regarding mix weight variation. Dimensionally, there are no differences in the metallic components because they are made on the same stamping lines as non-benchrest primers, using the same tooling.” – Jeff Siewart, Ballistic Engineer

Why Use Magnum Rifle Primers?

The most popular primer was the CCI #450 Small Rifle Magnum Primer. To be clear, none of these guys were actually using magnum cartridges. They were primarily using medium-sized, short-action cases like the 6mm Dasher, 6.5 Creedmoor, 6mm GT, 6mm BR, 25×47 Lapua, and other similar-sized cases. (View the data on what cartridges these pro shooters run)

So what’s the advantage of a magnum primer?

In the book Ammunition, Demystified, Jeff Siewart gives a thorough technical explanation of why magnum primers were invented (pages 147-148), and it has to do with how modern gun powders are made in order to provide optimal performance. I’ll do my best to summarize.

To get the best possible precision and highest possible muzzle velocity, you want a rifle case to be full of powder and for that powder to burn completely while the bullet is still in the barrel. Ideally, the peak pressure should occur farther down the bore, and the powder should be fully burned as close to the chamber as possible. That way, expanding gases push on the bullet for as long as possible without wasting energy accelerating unburned powder that exits the muzzle (which also hurts accuracy).

Modern powders achieve this balance using deterrent coatings and specific grain shapes. Smaller grains with high levels of deterrent coating burn slower on the surface but faster overall, helping stretch out the pressure curve and boost velocity – which is great for precision. But that also makes them harder to ignite, especially when the case is packed full, and you’re shooting in cold weather.

Magnum primers were invented to solve that ignition challenge. They produce more energy at the start, helping to consistently ignite large volumes of slow-burning, highly deterred powder, reducing velocity spreads and pressure inconsistencies.

Note: I share several practical tips on picking the optimum rifle powder from Jeff’s book in this article: Rifle Load Development: How To Find The Best Powder & Load For Accuracy.

Now, is that the reason the majority of these guys are running CCI #450 primers? I’m not sure. I can say the CCI #450 primers have proven to be very consistent. A magnum primer may give you a little more velocity than a standard primer, but the trend among the top shooters over the past 3-4 years is to run their bullets at relatively slow velocities anyway. I will add that I’m personally one of the top 100 ranked PRS shooters from this past year, and I use CCI #450 primers in virtually all of my match ammo that uses small rifle primers. I can attest that I get velocity SDs of 4-7 fps from my 6mm Dasher load, so I don’t see any reason to change it. That might be anecdotal, but I’d suspect most of these other pro shooters running it would say something similar.

Small Rifle Primers vs. Large Rifle Primers

You may have noticed that the overwhelming majority of primers these guys use are small rifle primers, even though some of these cases, like the 6.5 Creedmoor, were originally designed for large rifle primers.

98% of these pro shooters use either match-grade brass made by Alpha Munition, Lapua, or Peterson (view data on brass). All 3 of those brass manufacturers offer a few cases with the option for primer pockets made for either a Large Rifle Primer (LRP) or a Small Rifle Primer (SRP). The most popular example is the 6.5 Creedmoor. The original 6.5 Creedmoor case design from Hornady had a large rifle primer, but Alpha, Lapua, and Peterson are all offering 6.5 Creedmoor cases with a small rifle primer OR a larger rifle primer. They might also offer cases with the option for small or large primers in 22 Creedmoor, 6XC, 6mm Creedmoor, 25 Creedmoor, 260 Rem, 308 Win, and other cases.

I was curious how many of these top-ranked shooters opted for one primer or the other, so I did some analysis on it – and it’s pretty conclusive!

98% of these guys were running brass with small rifle primers! Only 3 people were running large rifle primers, and none of those were inside the top 100. In fact, 2 of those using a large primer were shooting a 308 Win in the tactical division (but still shot well enough to finish inside of the top 200 in the PRS Open Division). So, if you were wondering if you should buy the brass with a small rifle primer pocket or large – this group seems pretty definitive on that!

I will add that I’ve heard ballisticians from Hornady say that if you are using a Creedmoor-sized case in cold conditions (below freezing), they would highly recommend a large rifle primer. They say you could experience ignition problems trying to light powder in those cases that have over 35 grains of powder with a small rifle primer.

“Unfortunately, you see a huge push to the small primer pocket brass for match shooting in certain cartridges, like the Creedmoor family. We’ve seen quite a bit of that available. What a lot of guys don’t understand is that you’re skirting the line there with the combination of the charge weights that are used within those cartridges, the type of propellant that’s used, and then the small rifle primer that at generally at colder temperatures you can have ignition related issues with those. So that’s something to keep in mind. A small primer pocket isn’t just more material around the primer pocket, meaning you can stand on pressures, and your brass lasts longer. There are other things going on as well.” – Jayden Quinlan, Hornady Senior Ballistician

I personally competed with a 6mm Creedmoor for 5+ years and easily fired 10,000+ rounds with a small rifle primer in it without a single ignition issue – but very few of those rounds were fired below freezing. I was using CCI #450s and Hodgdon H4350. The guys at Hornady are experts, and that is only my anecdotal experience – but I just want to try to present a balanced view.

“It gets muddy because there are times where it’s like this primer works with, say, all 5 of these cartridges no matter what powder you put in it. Then you switch to this other powder in those same 5 cartridges, and for 3 you better use this primer, and for those two you better use a different primer, because if you don’t do that, then problems are coming.” – Jayden Quinlan, Hornady Senior Ballistician

I’ve also heard Jayden say that in the research they’ve done at Hornady, they’ve found no precision or consistency advantage to small rifle primers. He also hadn’t heard of any other serious research that had been done by other labs that would indicate some intrinsic benefit when it comes to small rifle primers for precision.

One reason many of these shooters opt for small rifle primers is the belief that more material at the base of the case around the primer pocket could either extend brass life or possibly support slightly higher pressures. I’d also bet that some people do believe that small rifle primers are potentially more consistent and might help precision. But, again, I haven’t seen any serious research (based on appropriate large sample sizes) that supports that conclusion. So I can’t confirm or deny that. 

If anyone is aware of research into small rifle primers vs large rifle primers, please share it with us in the comments!

Coming Up Next

This article is part of a series on rifle reloading data, load development, and reloading components. Here are other related articles that I’ve recently published or plan to publish in the near future:

• Best Reloading Presses & Dies – What The Pros Use
• Best Powder Scale – What The Pros Use
• How Do The Best Shooters Reload? What The Pros Use (This is all about the reloading steps and process that these shooters perform to reload their match ammo.)
• Best Brass – What The Pros Use
• Best Long Range Bullet – What The Pros Use
• Unlock the Secrets of Ammo: A Must-Read for Every Shooter and Reloader (This is a review of the book Ammunition, Demystified by Jeff Siewert, which is the best book I’ve ever read on ammo.)
• Best Rifle Powder – What The Pros Use
• Rifle Load Development – How To Pick The Right Powder & Load
• Powder Temperature Sensitivity – Why It Matters & Best Powders To Use
• Best Rifle Primers – What The Pros Use
• Best Match Ammo Options for Shooters Who Don’t Reload (coming soon)

If you’d like to help PRB, here are ways you could do that:

Shop Using My Amazon Associates Link

If you buy stuff off Amazon, use the link below, and I get credit regardless of what you get or from what country you order – and you pay not a penny more! Amazon has an affiliate program that pays a small commission when readers use links from my website to buy stuff. You still get your stuff at Amazon’s great prices, and you can help support PRB at the same time.

Donate to PRB

No pressure, but it does cost quite a bit to support the amount of traffic PRB gets, and I spend quite a bit of time creating all this content. If you get value from the content and would like to donate, I promise 100% of it will go towards keeping this thing going!

Share on Facebook & Your Favorite Forum!

It would help me out if you’d share a link to this article on Facebook and your favorite rifle forums so more people can benefit from the content.

• Facebook

Like & Follow On Instagram

View this post on Instagram

A post shared by PrecisionRifleBlog.com – Cal Zant (@precisionrifleblog)