Large rifle primer vs small rifle primer

Red_7.08

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Some manufactures sell brass with either option of SRP or LRP. Example - alpha munitions 308 brass. What would be the benefit of choosing SRP over LRP?
 
More robust case head, potentially less velocity deviation. Functionally speaking at hunting ranges it does not matter, other than in extreme cold a LRP is probably the safer bet.
 
The small primer is used mostly for target shooting. It has just enough primer compound to reliably ignite the powder charge which might produce more consistent results on targets. Most hunting ammunition features a large primer which has more primer compound to reliably ignite the powder under all conditions.
 
Less priming compound tends to yield more consistent velocities IF you can still reliably ignite the powder charge. Cases as large as the 308Win and 30TC(parent of the 6.5CM) are really on the edge. Some competitive shooters swear by it, and others swear that small rifle primers give them fits.

A side benefit is that the extra brass around the primer pocket results is less primer pocket expansion, so guys loading way over max pressure can potentially get more firings out of their brass.

They really originated due to the use of 308Win brass to form smaller cartridges for competitive shooting, primarily the 6BR before BR brass could be purchased. Most of the wildcats used in competition as alternatives to the PPC were quite small and didn’t need a large rifle primer to ignite the powder, and did benefit considerably on the accuracy front from using a smaller primer. Before small rifle primer 308Win brass was available there were guys bushing primer pockets to use small rifle primers in brass with large rifle primer pockets.


It’s not something to get too hung up on. The best bet in terms of avoiding any potential MINOR problems is to stick to a large rifle primer in something like a 308Win or a CM.

If you were to form 6BR brass from large rifle primer 308Win, most hunters and shooters would not know the difference, but doing so for benchrest competition would make it very difficult to do well in matches regularly. The degree to which it effects accuracy, even in a small case like a BR, is fairly small. In a larger case, it is likely non-existent in the best scenario and perhaps detrimental in certain scenarios.
 
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