# .308 Win vs .308 Win Palma?



## Bax* (Dec 14, 2008)

Can anyone shed some light on the difference?

I was looking at Lapua's website and saw the brass for the Palma, and I know that they generally shoot the 150 grain Sierra bullet, but I saw something that caught me off guard on Lapua's website. It said the following regarding the Palma brass:



> Lapua is proud to introduce the new .308 Win. Palma case. Developed in conjunction with the US Palma team, the *small rifle primer case* is designed to deliver enhanced long-range accuracy for the most demanding competitive applications.


What benefit would this provide to use a small rifle primer in a case that generally uses large rifle primers? I couldnt seem to find any differences in case dimensions though. Any thoughts? -Ov-


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## longbow (Mar 31, 2009)

I use to have a 22 CHeetah and the brass was formed out of 308 Win BR brass. It had a small primer pocket for more uniform ignition (they say) and lighter, more uniform cases. They discontinued making them several years ago and everyone went back to large primer pockets. So now it sounds like they're coming back. I work with some palma shooters but honestly I don't know very much about it. I know the gun has to be a 308 with open sights and you have to use a 155 Sierra MK HPBT.


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## Frisco Pete (Sep 22, 2007)

> What benefit would this provide to use a small rifle primer in a case that generally uses large rifle primers?


I suppose as a part of the uniform ignition thing is why competition rifle shooters often favor mild primers _i.e._ primers that produce just enough heat to properly ignite the powder. They feel that as primer brisance gets higher, it also gets less repeatable from primer to primer. Another train of thought is that the powder is ignited a tad more gently. When this happens, the front slope of the pressure curve is less steep. Which means the bullet is pushed a tad more gently into the rifling which tends to deform it less. Whatever the scientific reason, competitive rifle shooters seem to feel that the milder primers give both better velocity uniformity and accuracy.
You can only go so mild with LR primers, after that you have to take the next step down and use Small Rifle primers to get milder ignition.

The .308 case isn't really big and the powders typically used by Palma competitors are fairly easy to ignite, so evidently a SR primer gets the job done.

I understand that some .22 CHeetah owners ran into ignition problems in very cold weather depending on the powder used because of the SR primer, but I have no firsthand experience. The Palma stuff isn't intended for all-temperature extremes varminting like the .22 CHeetah, so the problem likely wouldn't crop up.

In general, I don't think any of us would notice any advantage by switching to SR-primered .308 brass - and there _can_ be downsides as to ignition under adverse conditions, at least with some powders anyway.


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