Large rifle primer vs small rifle primers - 6mm

[huntsd]

School me on the differences. Is the argument that small will be more consistent and is less wear on the primer pockets. Large is better for hunting in low temps?

Question is specific for 6mm cartridges

 

[kpk]

yes and yes.

I just ordered large simply because I have twice as many large primers on hand.

 

[wind gypsy]

Small: More brass thickness around pockets so primer pockets are more resistant to expansion from pressure. SRPs can be slightly cheaper and more available.

Large: Put out more spark which can be helpful depending on how much powder you're trying to light, temperatures, and how much spark a given powder needs to function reliably.

Single base stick powders typically require less spark than double based or ball powders.

Lots of people do well with SRPs in cold weather still. I prefer a little extra buffer with LRP and i've always had plenty LRP to keep up with needs.

 

[huntsd]

Small: More brass thickness around pockets so primer pockets are more resistant to expansion from pressure. SRPs can be slightly cheaper and more available.

Large: Put out more spark which can be helpful depending on how much powder you're trying to light, temperatures, and how much spark a given powder needs to function reliably.

Single base stick powders typically require less spark than double based or ball powders.

Lots of people do well with SRPs in cold weather still. I prefer a little extra buffer with LRP and i've always had plenty LRP to keep up with needs.

are es/sd typically better with small?

 

[Ice-kub]

Serious question to add to the above question. What about small rifle magnum primers for a use case in cold environment?

 

[Ac338]

Serious question to add to the above question. What about small rifle magnum primers for a use case in cold environment?

I’ve been using srp Rem 7 1/2 in my 223 AI coyote gun for the last three years and I’m yet to have a misfire. A few nights ago we were at -16 and with gun and ammo being in the bed of the truck for 6 hours it still went bang when I needed it

 

[Ice-kub]

I’ve been using srp Rem 7 1/2 in my 223 AI coyote gun for the last three years and I’m yet to have a misfire. A few nights ago we were at -16 and with gun and ammo being in the bed of the truck for 6 hours it still went bang when I needed it

Good to know! Any issues with pressure when getting up into more mild or hotter temperatures?

 

[Ac338]

Good to know! Any issues with pressure when getting up into more mild or hotter temperatures?

I haven’t noticed any pressure signs I haven’t shot that load in any temps over 50-60 degrees though. 50 grain vmax 26.0 grains of h335

 

[Lawnboi]

I’m assuming you’re talking 6creed.

I just buy LRP brass to avoid ignition problems. It’s not 2020 anymore and large and small rifle primers are attainable. I have shot both and see zero difference besides I have seen srp creed brass have hang fires in cold temps.

In the larger cases LRP also handle pressure to the primer better. Both will last a barrel if you’re getting quality brass.

 

[S.Clancy]

My experience with SRP's in cold temps has been awesome. I just use CCI 400's, have shot as low as -5F or something with no trouble firing.

I think people that run into trouble are shooting powders where you are using 45-48 gr. I'm shooting 41-41.5 gr of H4350 and it's fine.

I will say I saw CCI 200's and 400's are the same price at Scheels, so it's kind of sixes. I have 6 reloads on my SRP brass and it looks great.

 

[NRA4LIFE]

The person who thought it was a good idea to make a cartridge with both sized primers should be neutered.

 

[Firestone]

Better life of primer pockets with small is the only difference I have seen. Both can shoot low es/SD, both work well in cold temps

 

[mtnbound]

School me on the differences. Is the argument that small will be more consistent and is less wear on the primer pockets. Large is better for hunting in low temps?

Question is specific for 6mm cartridges

I have brass in both, and I have always ran SRP Magnums because I could find them easily as compared to LRP and never had a problem with them going bang until recently when I tried Staball powder and started getting some delayed fires. I switched to the LRP brass with the same powder and did not get any delayed fires, so I am staying with the LRPs until they become impossible to get.

 

[Flyjunky]

I have brass in both, and I have always ran SRP Magnums because I could find them easily as compared to LRP and never had a problem with them going bang until recently when I tried Staball powder and started getting some delayed fires. I switched to the LRP brass with the same powder and did not get any delayed fires, so I am staying with the LRPs until they become impossible to get.

Interesting, I haven’t heard of problems when using srp magnums. Good to know, thanks.

 

[mtnbound]

Interesting, I haven’t heard of problems when using srp magnums. Good to know, thanks.

I was shocked when this happened because I had used SRPs without any issue until that day. I have read about guys having problems, but I figured it was BS to be honest.

 

[wind gypsy]

The person who thought it was a good idea to make a cartridge with both sized primers should be neutered.

Why? What’s so difficult about it?

People were wildcating SRP 308 Palma brass to get SRP pockets so might as well give the people what they want.

 

[wpeach1912]

I don’t think there’s a consistency difference. At least not noticeable. Potentially the case handles pressure better on SRP brass. For hunting, I think run large. I have all SRP 6.5 creed brass and exclusively use 450s. I have had a few unexplained hangfires or no fires, that may or may not be a primer size issue. I would say it is more likely to happen with small than large though.

 

[Lawnboi]

These hang fires are the noticeable ones. How many are unnoticeable and increasing lock time in the system.

It was awesome having srp brass available for the last 4 years when LRP were unobtainable but now that they are I see zero reason not to use LRP for a hunting gun.

 

[S.Clancy]

The person who thought it was a good idea to make a cartridge with both sized primers should be neutered.

I think manufacturers did it during COVID because LRP's were so hard to come by. I could buy CCI 400's basically any time I wanted.

 

[TaperPin]

The demand came from the small accuracy advantage in 308 and smaller cartridges, which is well documented, but my gut says it would be very hard to see unless your gun will shoot .2 or .3 MOA. A lot of videos shooting groups with both and not showing much of an advantage or disadvantage. If they were better for the average shooter, even 1/16 MOA better, every cartridge would use small primers and large primer brass for any of the short cartridges would be rare. I see it as an artifact from aggressive marketing more than anything else. None of my friends can point to one of their

It seems at least part of that accuracy advantage is being able to throttle the pressures up. Why I don’t know, but the benchrest crowd is full of guys with loads shooting best at the bleeding edge of leaking primers and stretched pockets.

There’s a good deal of half truths floating around about the compatibility of thick factory firing pins and small primers. Unless you’re shooting .2s at high pressure I would be very surprised if firing pin thickness makes a lick of difference, but it’s a bragging right thing and I’ve never met a gunsmith or custom receiver builder that suggests doing less work on a rifle. My point of reference for why this is a nothing burger for hunters is with the .222 many of which were very very accurate and fired 10s of thousands of rounds at varmints. Not a single prairie dog could tell the firing pin was kinda chonky. True facts.

*chuckle*