Large primer vs small primer

[REDGUN]

I noticed the Lapua Palma 308 brass, with the small primer pocket, and was wondering what are the Pro's and Con's of using a small rifle primer???

 

[KevinThomas]

REDGUN,

The small primer Palma cases were made for a very specific purpose; Palma competition. The small primers tend to be easier to sort for long range performance than do the large primers, which generally show more vertical dispersion if you just randomly grab a lot and start loading. Most serious LR competitors go to some pains to select a "good" lot of large primers, to reduce this vertical dispersion as much as possible. The small primers just seem to be a bit more forgiving in this regard. So on the "Pro" side, you've got some potential for easier primer selection and possibly (and I stress, "possibly") better accuracy potential.

On the flip side, Palma and other LR matches are generally shot in pretty decent weather (many in summer, and fairly warm temps), and the powders favored for this type of competition would normally be classed as being of medium burning rates. Extruded tubular powders are the rule here, and you don't see nearly so many ball powders being used for this game. Ball powders are generally more difficult to ignite than extruded types, and all powders become harder to set off as the temperature falls near the freeze point. Add to that the fact that a full 308 case of powder is about the outside limit of what a small primer can reliably ignite under optimal conditions. Combine these factors for the average hunter, and you can see the problems. A very large charge (max hunting load) of a ball powder, sitting in the woods for several hours at around freezing temperatures, and you have all ingredients for a hang fire (at best) or a complete failure to fire when the powder charge doesn't ignite. That's the "Con" side. For these applications (and the vast majority of things that a 308 normally sees use), just stick with the standard Large Primer case, and you'll be better off. Sure ignition, no noticable accuracy loss for these applications, and the peace of mind that comes with knowing the round will fire when you tickle the bang switch.

Hope that helps.

 

[jonbearman]

Kevin you made reference to sorting primers,can you elaborate to this concept?

 

[people]

I sort mine by brand then type.

 

[Tozguy]

Kevin,
Thanks for the explanation above. It helps me too.
Mike

 

[spclark]

Kevin, thanks for the essay on how your Palma brass came to be.

I've shot both 308 versions & found virtually no difference between the two save for the better SD's with SR primers, often with exactly the same load save for primer selection.

The Palma brass also can be used to make superb 6XC cases BTW! All the advantages of using small primers transfer to another cartridge if one's willing to work out the sequence of operations sizing the cases down as needed.

 

[hoverp]

So Kevin, if you we're going to set up a round for Palma competition, using 43-45 grains of varget , and lapua brass pushing the 185 LRBT Berger loaded long , for 800-1000 yard sling and irons, would you go for the lapua Palma cases or the large rifle?

What primers do you favor in either case?


Thanks.

 

[spclark]

So Kevin, if you we're going to set up a round for Palma competition, using 43-45 grains of varget , and lapua brass pushing the 185 LRBT Berger loaded long , for 800-1000 yard sling and irons, would you go for the lapua Palma cases or the large rifle?

What primers do you favor in either case?

If you have a half-MOA hold the Palma brass might be your best choice. Either will give half-MOA accuracy or better, the rest is up to you.

I'm sold on the Wolf products; KVB-223REM & KVB-7. Next'd be the CCI BR choices but they cost more.