Primer choice

[rwade545]

I have been reloading for my .22-250 and have found it shoot well with a middle of the road load so not pushing it too hard to help preserve barrel life, have been using cci 200 primers with it.

Recently i have started reloading for my .308 with a 20" barrel. Velocity is always going to be a problem. I am loading 175grain Berger OTM with lapua brass and cci-200 primer and h4895 ( ideally would like varget but non local). The load data is 37-41grains as per berger. grouping were improving as the load went up. at 40.5 group was .5" at 100yard, and slightly better at 40.7 grains but primer began to flatten so stopped there. Are they other primers that people find harder and less prone to flattening? Know i will have to start low again and work up with the change. Will the change form vigin brass to once fired make much difference?

Reason for pushing velocity is that i want to shoot longer ranges when given the opertunity and would like to have a load that can do 1000yard if given the chance wich willrequire as much velocit as i can get out of the 20" barrel.

Have recently got a chronograph so can see what velocity i am getting next time i am out.

I also have a 150grain load with 39.7grain of H4895 that shoots well with lowrecoil for shorter ranges and keep cost of the berger otms down.

Regards

 

[Muir]

I have been reloading for my .22-250 and have found it shoot well with a middle of the road load so not pushing it too hard to help preserve barrel life, have been using cci 200 primers with it.

Recently i have started reloading for my .308 with a 20" barrel. Velocity is always going to be a problem. I am loading 175grain Berger OTM with lapua brass and cci-200 primer and h4895 ( ideally would like varget but non local). The load data is 37-41grains as per berger. grouping were improving as the load went up. at 40.5 group was .5" at 100yard, and slightly better at 40.7 grains but primer began to flatten so stopped there. Are they other primers that people find harder and less prone to flattening? Know i will have to start low again and work up with the change. Will the change form vigin brass to once fired make much difference?

Reason for pushing velocity is that i want to shoot longer ranges when given the opertunity and would like to have a load that can do 1000yard if given the chance wich willrequire as much velocit as i can get out of the 20" barrel.

Have recently got a chronograph so can see what velocity i am getting next time i am out.

I also have a 150grain load with 39.7grain of H4895 that shoots well with lowrecoil for shorter ranges and keep cost of the berger otms down.

Regards

I shoot Remington 9.5 primers and like them. They are a harder cup than the CCI's -at least in my experience. The thing is that if you know that the flattening is due to the cup, not pressure, then you can live with it. I shoot a few loads with CCI and know what I'm looking at.

Unfortunately, Varget and 4895 are poor choices for the 175 grain. I also shoot a 20 inch 308 and shoot IMR 4064. It is a far better choice than either of the other two to the extent that the US military has specified it for their match 308 loadings with 168 and 175 grain bullets. With 168's at 70- degrees F I am getting 2740 fps with and standard deviation of 12 fps from military brass. I was shooting this load at 800+ yesterday and having all the success the angry wind gods would allow on a 10" square steel plate. With 4064 and a 175 it is easy to stay above transsonic to 1000 depending on the altitude. That is the only benefit to added speed. Your trajectory will be a high arc no matter what -a few extra fps won't help trajectory much. ~Muir
PS: I've attached the spec sheet from Federal. Note that this their special long range load.

 

[rwade545]

Hi, thanks for that. Looking at Hodgdon load data that is at the lower end for the smk 175.presumably so it does not show pressure in a variety of rifles. The Berger data for the 175 otm lists the max for the Berger at 42grain. Possibly greater bearing surface area giving greater friction.