What does small-primer 308 brass do for me?

[HomeSlice]

Thanks in advance for looking.

I see a lot of people using this stuff. Not sure why? What does it do for me that regular 308 brass won't do?

My use case is F/TR. I've just re-barrelled, so now is probably the time to make the switch if I'm going to do it. I do have quite a bit of regular 308 lapua brass and federal 210m primers already, so unless there's a really good reason to switch, i probably won't.

Thoughts?

 

[Down South]

Accuracy wise I didn't see much difference between the two (large and small). The small primer brass is much tougher in the pockets and will hold up to higher pressure loads that will kill large primer brass pockets rather quickly. If you have large primer brass already and don't run hot loads I'd shoot it until it's toast then switch. If you plan on running stout loads I'd sell the large primer brass and buy the small primer brass. Just my .02

 

[Texas10]

You know what they say, "smaller is tighter".

 

[Crow]

If you end up shooting FTR for a while, you'll likely transition to SRP brass at some point. No better time than when you're starting from scratch with a new barrel...

 

[riflewoman]

The theory goes that small primers give less violent ignition and therefore less deviation in shot to shot velocities. These translate into smaller vertical dispersion at 800 to 1000. I dunno. I do know I used to shoot SRP 308s at 600 (Remington BR Basics) with a 190 and 42,2 4064 that gave me 14x at 600 one day (iron sights) , shot like lasers they did. I do know that ignition gets iffy below 40 degrees with some powders and primer selection here is critical. As always YMMV.

 

[Rdlningcltchdmpr]

Thanks in advance for looking.

I see a lot of people using this stuff. Not sure why? What does it do for me that regular 308 brass won't do?

My use case is F/TR. I've just re-barrelled, so now is probably the time to make the switch if I'm going to do it. I do have quite a bit of regular 308 lapua brass and federal 210m primers already, so unless there's a really good reason to switch, i probably won't.

Thoughts?

It prevents you from using ball powders - causes hangfire's..

 

[riflewoman]

It prevents you from using ball powders - causes hangfire's..

Is that a good thing or a bad thing?

 

[HomeSlice]

The theory goes that small primers give less violent ignition and therefore less deviation in shot to shot velocities. These translate into smaller vertical dispersion at 800 to 1000. I dunno. I do know I used to shoot SRP 308s at 600 (Remington BR Basics) with a 190 and 42,2 4064 that gave me 14x at 600 one day (iron sights) , shot like lasers they did. I do know that ignition gets iffy below 40 degrees with some powders and primer selection here is critical. As always YMMV.

OHHH... this gives me a little pause.

I'd most likely be using Varget, with the cci BR primers. We shot in the snow a couple of years and it was colder than hell.

How big of a problem is this?

 

[ebb]

The benchrest crowd used to say if it is much over 40 grains of powder, a small primer starts to get iffy.

 

[riflewoman]

OHHH... this gives me a little pause.

I'd most likely be using Varget, with the cci BR primers. We shot in the snow a couple of years and it was colder than hell.

How big of a problem is this?

https://m.youtube.com/playlist?list=PLTTrjvDib94m9twQ7mD937yNMOT-7JQEy

this guy ran a bunch of tests.

 

[JEFFPPC]

https://m.youtube.com/playlist?list=PLTTrjvDib94m9twQ7mD937yNMOT-7JQEy

this guy ran a bunch of tests.

That's not fair, pitting urban legend against actual testing.

 

[Lefty Trigger]

I was told that the small primer brass will withstand better/higher pressure pushing against the primer.

 

[Longtrain]

It adds another level of testing to your load development. Just as soon as you figured that 43 grains of Varget under a 185 Juggernaut lit by a BR2 primer can win F-TR matches, you wonder about using a BR4 and then buy new Lapua cases and start your testing all over with Wolf, Tula, Federal, Rem 7 1/2, etc, etc.

That was a bit tongue in cheek, but a good HM F-TR friend went that route, he found a little lower SD, but no huge improvement over large rifle primers.

 

[mongo chicago]

I see it as basically an answer to a non-existent problem

 

[XTR]

@HomeSlice the majority of F-TR shooters are running SRP brass. I think that the SRP and the loads we run probably put us at the edge of reliable ignition (more below) but the brass lasts longer running at ±90% of SAAMI spec where we tend to load, and the loads shoot well.

I've run some of my SRP loads with a pressure trace system and it shows that at least with my Tula primers I was definitely getting delayed ignition, not hang fires per se, but there is a pronounced step in the pressure curve. I have gotten hang fires with Tula primers and N150 at low temps. I've since switched to 205m primers and haven't had issues down to 30ish degrees.

If you are going to shoot F-TR there is good reason to shoot SRP brass.

 

[BronzeArcher]

I wouldn't mess with it if your only application is mid-range (300-600 yards). No need to push pressures and no spanking for a bit more velocity spread.

I also wouldn't mess with it until you are consistently shooting Master level scores at long range (800-1000 yards). You have lots of higher priorities than small primers. Sort out those issues with your existing brass.

But once you are consistently shooting Master or High Master scores at 800-1000 yards, the Palma brass will probably add a couple points to your scores in a 60 shot tournament, and it will certainly extend your brass life for getting good velocities out of 200+ grain bullets.

 

[Rdlningcltchdmpr]

Is that a good thing or a bad thing?

It's bad. I like using ball powders for many loads. There is no down side with large primer's.

 

[Dave Marshall]

The only real benefit is potentially longer brass life in regards to primer pockets. However, if you bump your shoulders too much, the cases will still separate.

I’ve gotten low single digit SD’s with LR primers easily.

 

[Ned Ludd]

If your rifle is chambered with plenty of freebore, let's say at least 0.125" to 0.150" for a Berger 185 Juggernaut or 0.170" to 0.180" for a 200.20X bullet, you will likely be running pressures of around 59K psi to just under 62K psi to hit the commonly-used accuracy nodes that F-TR shooters often run (~2720-2740 fps for 185s over Varget from a 30" barrel, ~2640-2660 fps for 200.20Xs). Even though SAAMI MAX pressure for the .308 Win is 62K, the primer pockets in Standard .308 brass (LRP) will not last as long at those pressures as the SRP pockets in Palma brass. Running a load with 185s that was predicted to be at ~61K psi (QuickLoad) in Standard .308 brass gave me around 4 to 6 firings. In SRP Palma brass, I can't even tell you the average number of firings that same load would give, because I haven't gotten there yet, but it's at least 12 to 15, or more. The increased case head thickness and extra metal around the primer pocket makes Palma brass far more resistant to the [relatively] high pressures we often run in F-TR loads.

I have used Palma brass for several years now and wouldn't even think about switching back. I regularly practice during the winter season when ambient temps are between 30 to 40 degrees, using loads with 185s, 200.20Xs, and 215s over Varget with Fed 205 primers, and I have yet to experience any ignition issues. I suspect that ignition with small rifle primers and Varget loads is more likely to be an issue when ambient temps get below the upper teens to mid-20s, rather than in the 30s to 40s. Of course, that may change depending on your chosen powder and the brisance of the the primer you're using.

 

[Tommie]

Wow. Good video. I’ve never seen so many hangfires!