Small rifle primers in .308?

Been curious for a while and with shortages, figured this would give some versatility to what I can use. I bought some of the .308 brass from Graf's that uses small rifle primers rather than large. I want to see if they make any difference with reduced cast loads in my .308 target rifle I've been working with the past year and a half or so off and on.

Any thoughts? I tried some small pistol primer .45 ACP brass a few months ago, and it actually seemed to shoot a little better for me, though I didn't shoot enough to be positive.

I’m sure they will work fine. With mild cast loads, I would even try small pistol primers in it. Just load about 5 and see how it goes. But I have much more SPP than SRPs. If the SPP gets pierced by the firing pin, I’d stop the experiment. Years ago, I loaded full strength .22 Hornet and .218 Bee with pistol primers with good results but that doesn’t mean it’s ok for every other gun.

It's long been a practice for Hornet shooters to use small pistol primers. I only shoot light cast loads in the Hornet.

I did shoot up a bunch of somewhat questionable large pistol primers in my practice loads in the 7x57 (135 grain cast, 10 grains of 700X). No problems there.

Small rifle primers will work fine for most powders that are not the harder to ignite ball powders, 4064, 4895, Varget, RL15 do just fine. Ball powders are 'OK' if it is warm, say 40* and up. Accuracy may improve with the 'lighter' loads using Unique, 2400, 5744. Drilling the flash hole could help if ignition seems borderline (occasional hangfire). I have both large and small primer brass for the 6.5 Creedmoor, haven't found much difference in performance. Softer/milder primers are believed to produce better accuracy by many.

I am planning on trying some Federal small rifle Match primers in my small pistol applications. I want to just prime some cases and see if they will pop in a pistol . Then try some loadings. It's a case of using what you 've got.

I have 7.62x39 R-P cases that take SR primers and I have Winchester and IVI that take LR primers. With full power loads using Lee 155 gr cast the LR primers, given the same load, do generate a bit more psi (measured).

However, I also have converted several different Berdan primed cartridges of close to 308W case capacity (no 308W though) to take SR primers. With the same cast bullet loads the psi generated is close to that when LR primers are used in commercial cases for the cartridge. I was using WSP and Rem 7 1/2 primers vs WLR primers. Using other primers will probably give +/- pressure increases as a change of primers many time does.

I still have some of that SRP 7.62x39 brass around that I got to shoot in a bolt action. Always wondered why a little case like that is loaded with large primers.

We're in the rotten weather phase of things when day light is short and when I'm not busy on weekends, it's raining or snowing so not getting much shooting in, but I hope this will be interesting to try in my target rifle when I get back to shooting it.

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Originally Posted by richhodg66

I still have some of that SRP 7.62x39 brass around that I got to shoot in a bolt action. Always wondered why a little case like that is loaded with large primers.

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The most likely reason it was designed to large primers had solely to do with the USSR already having the production equipment and processes for large primers in place that would work. While they had small pistol primer for the 7.62x25 set up, they would have had to come up with new dies to make the cups.

And they came up with the round during a war that they weren't 100% sure was going to end soon.

Much like the Germans basing the 7.92x33 on the 8mm Mauser case, even when the knew that a smaller case diameter would be better. They did that solely to be able to use the same tooling.

I remember the Remington 308 BR brass that was used by the Benchrest crowd and also the case-forming crowd that had small primer pockets. There are mixed reviews all over the web regarding this brass.

Starline has some SP 308 "Match" brass for sale also if you can find it:

https://www.creedmoorsports.com/prod...ss-cases/Brass

I experimented with 22-250, 243, and 308 / 762 x 51 converted to SRP some years ago. I turned up steel sleeves and pressed them into cases then swaged to size. Results were interesting in my rifles 22-250 was in a AR10 krieger barreled 1-7 twist, 243 was in 2 rifles AR10 krieger barrel 1-7 twist and a pre 64 model 70 hart barrel 1-7 twist .267 neck, the 308s were in 2 national match M1As krieger 1-10 twist heavy barrels. bullets were jacketed and Heavy long for caliber. 80 grain jlk vlds in 22 cal, 105 jlk vld and 115 berger vlds in 243. 168 hornady and sierra bt hp match in 308.

In 22 and 243 I saw slightly improved accuracy slightly better ES and SD numbers. The accuracy improvement was hardly noticeable at 200 yds but at 600 out did show. In 308 the es and sd showed a slight improvement but accuracy stayed basically the same. I suspect the lighter bullets didnt "reseat" with the srp primers. had thought about trying srp in my 6.5 wild cat based on a shortened 300 wsm case, But never got around to it. Did chronograph primer only with pellets in the 22-250 as expected the srp were slightly lower velocity than the lrp .

Another added benefit is when using reduced loads in 308 the headspace dimension of the cases doesn't shrink, at least on the Starline cases I've used. No need to fully fireform and drill the flash holes.
Rick

The answer may not be as easy as hoped. I read an article by a respected gun writer who wanted to use small primer brass in his 6.5 Creedmoor. He called Hornady, Federal, and a powder manufacturer. His negative replies weren't all polite. Small primers do theoretically offer better accuracy potential, but all his sources claimed the flame isn't enough for 40 grain powder charges, expecially in cold weather. I can vouch for their inability to ignite 40 grains of graphite-coated double base powders. Small non-magnum CCI primers led to hangfires in my 45-70. WW primers did work. Lapua makes small primer 6.5 Creedmoor brass, but their flash hole is very small. Think of the flash hole like a hose nozzle, the smaller the hole, the longer the flame. Primer flame should closely match the length of the powder column.
Happy experimenting, but be cautious about hangfires.

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Originally Posted by Norske

The answer may not be as easy as hoped. I read an article by a respected gun writer who wanted to use small primer brass in his 6.5 Creedmoor. He called Hornady, Federal, and a powder manufacturer. His negative replies weren't all polite. Small primers do theoretically offer better accuracy potential, but all his sources claimed the flame isn't enough for 40 grain powder charges, expecially in cold weather. I can vouch for their inability to ignite 40 grains of graphite-coated double base powders. Small non-magnum CCI primers led to hangfires in my 45-70. WW primers did work. Lapua makes small primer 6.5 Creedmoor brass, but their flash hole is very small. Think of the flash hole like a hose nozzle, the smaller the hole, the longer the flame. Primer flame should closely match the length of the powder column.
Happy experimenting, but be cautious about hangfires.

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This is going to be used in a Winchester Model 70 Heavy Varmint I got specifically to shoot cast at 100 yards with, I seriously doubt it will see 40 grains of anything in this endeavor. More likely charges of Unique, Herco, 2400, etc.

I played with Remington URBR brass some years back in 308 and necked down/fireformed to 6.5 Creedmoor. I did experience a few hangfires but they were attributed to the specific primer (Wolf/Tula). I got that sorted out but the Remington brass was very thin where it counted and wasn't quite what I planned. The brass was originally designed to reform to 7BR/6BR, not necessarily for use in the 308. I still have a pile of it in my "save for future use" cabinet.

The above stated, I have used Lapua Palma brass with fantastic success in 308 and necked down/fireformed to 6.5 Creedmoor. I did the neck down/fireform gig before Lapua made the SR Creedmoor brass. Anyway, though I don't live in an area where we experience extreme low temps, the Lapua brass has behaved fine with no issues with failure to fire. As another posted, I suspect it's due to the small flash holes (requires a small decapping pin or you'll regret it almost immediately). The Remington URBR brass has a washtub for a flash hole...

When Lapua started with the Palma brass, it was for the Palma crowd who shoot the 308 at 800, 900, and 1000 yards. It was designed to help make for small ES/SD. Using an Oehler Chronograph I can say I saw some very small numbers and fine accuracy. I also haven't worn a piece of it out either. It didn't reinvent the wheel, but it did improve rolling resistance so to speak. Other boutique brass producers have followed suit with SR small flash hole brass.

Not that you asked, but I use CCI 450's exclusively with these types of cases now.