The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

Hi folks,

I shoot a 6.5x47 lapua and would like to take my velocity spread down a bit. Its currently around 20fps from fastest to slowest and its running around 2940 fps with 38.8 gr reloader 15 in a 27" border 5R barrel.
I use rem 7 1/2 br primers but I never hear of anyone else using them for this cartridge.
What primers do any of you folf use in this cartridge?
I understand that the rem 7 1/2 br primer is a prety hot primer, is this correct?
Ideally I would like single figure spread but would settle for as besy I can get

Any suggestions folks?


Garry

I use CCI in all my loads, never had a problem or complaint.....

Is there a chart which lists primers of different makes from slowest to fastest or similar?

DM

Originally posted by MRY on GT

"Primers are as much a variable component as any other in reloading and can alter velocity and trajectory and therefore accuracy quite considerably.

I have long been an advocate of using primers in the same way as powder to vary a load with great effect.

We dont choose our case because one looks shinier than another but because of the chemical composition that is most suitable for our particular load. Neither do we choose a Powder just because the local shop has it on the shelf and so with Primers - choose your primer to do the best job possible for the load you are generating.

A change of primer can in some loads require a drop of 3 grains and the difference in velocity without any increase in pressure can equally improve by 100fps. Use your primers in the same way as your powder and you will be surprised at the difference your loads will provide.

Here is a basic heat chart - from top to bottom drop about 5-6% in powder and work from there.

Use it as a guide and add in your own primers when you have assessed them. eg, the Prvi Partizan Primers although burning approximately as hot as the Winchester range do because of their different construction not seem to require a reduction in powder when changing from say Remington. Try for yourself and let us all know your test results as it will expand the above chart considerably.

Use of Magnum primers is normally reserved for the Ball Powders but I am finding I can use them to great effect in the shorter stumpier cases such as the WSM and WSSM range of cartridges. Logically this should also be valid for the Benchrest PPC cartridges.

The same is true for the H4831 SC powder in 243 - A Federal Magnum primer seems to provide anything up to 120 fps higher velocities than standard primers yet seemingly without additional pressure.
BUT
do drop the powder weight and build up again.

Please remember to drop powder weights when changing primers and do also remember that with the present hot weather you need to reconsider all those max loads and take out a little powder.

A 10 degree rise in temp requires a 5% decrease in powder. If we are going to get such varied weather in coming years it may be best to have a min, intermediate and max load to use dependant on weather temperature."


HTH

CCI BR seem to work well in the Vikings 22-47, in fact they have never missed a beat for her and ES is very low. Not a true comparison but it is the same parent case

EDIT - handy chart Rob, for that.

Thanks for the replies lads and thanks for the primer chart as thats the one I was looking for, id found it before but couldnt remember where.
Funny thing is for these rem primers to be regarded as being hot, I use them with varget in my 223 and they give me very low spreads of 7 or so so im a bit baffled as I thought that in the bigger case they would work better.
I must buy some cci and see if theyre any better.

Garry

i swiched from cci to fedral for pistol calibers,my press dident like em! but i find cci fine on the stalking rounds and other cf ammo.

That chart gives the heat of the primers what is more improtant for accuracy with primers is its brisance and consistency of same.

Gussy of Cabine Tree did a test and the results were very interesting, the Russian Muroms came out very well and I used 5,000 of them when they were available and found them to be good but the supply dried up. They were packaged under PMC for a while and I used them also to good effect. Haven't seen them for a while now either.

Gussy's results are here:

http://www.castingstuff.com/primer_test ... erence.htm