G'Day Guys
I may have posted this twice.
Anyway can some one explain to me the benefits of a small primer used in a 308 Palma Lapua size case and I have seen that 6.5 Creed is now coming out in small primer.
I ask this as my 6.5 Epps project in nearly finished and was looking at experimenting to convert large primer pocket to small. I read some time back that it can be done but cant remember on how they did it or if the bushes are still available.
The 6.5 Epps is a 303 Brit neck down and Ackley Improved.
Cheers
Varmtr
The small rifle primer is slightly more accurate in small bench rest cartridges because of the more concentrated flame front and has a better/more controlled burn. and on small cartridges it appears to have an advantage of .020 to .030 in group size with very little improvement in SDs.
On larger cases there is essentially no measurable difference in group size, but some like to think there is and maybe in there rifles there is enough difference to them to warrant the work to change over. I fired 308s in matches for many years and saw no advantages in this size case, and in cold weather it proved to be a disadvantage to use small rifle primers.
Years ago I experimented with small primes, flash tubes for forward ignition and other changes in primer use to see if these changer were worth the effort. It wasn't in the cartridges I used and changes if the brisance of the primers (Different brands and non magnum primers) proved to have more effect on accuracy. One such case was the use of large rifle primers instead of magnum primers in cases with less than 70 grain powder capacity brought SDs down to single digits.
In cases with 40 grain capacity just changing brands made more accuracy changes than the small primers did.
It is a lot of work to change to small rifle primers unless you can find cases that already have small rifle primer pockets, then it is worth the effort to try and see if they can improve enough to change them.
In Some things, the gain is not worth the pain unless you are looking for any improvements no matter how small.
To satisfy your curiosity you should try them anyway. I made my own bushing that threaded in (32 pitch) to keep from softening the brass and make it stay in the case when de capping. It is also best to reduce the flash hole size at the same time.
At the least, it is an interesting process and worth the effort in knowledge gained. the 303 may be to large for and noticeable change But the fact you are interested is enough to try.
Good Luck and good shooting
J E CUSTOM