308, Ramshot Big Game, and 220grSMK / 215gr Berger Hybrids

Beluebow said:

First thing I would do is find touch with those two bullets. Chances are your rifle doesn't have enough freebore to get the boattail junction out of the case. This is going to eat up a lot of case capacity that you will probably need to make any kind of decent velocity.

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med358-boise said:

First I would call Sierra, Berger, and Hodgdon. They sometimes have unpublished data not on their websites that they will share.

If that inquiry was unsuccessful, you could consider looking at Hodgdon's website at loads for 190, 200, and 210 grain cup and core bullets, you will see that starting loads drop about 1.5 grains per 10 grains of bullet weight increase. So if I was faced with this dilemma , I would look at the 208 grain hornady starting load of 41.1 and drop to 39 then drop another 5% (for add'l safety purposes) to 37 grains. I would then start with the Bergers (you only have six and they are essentially throw ways) and load 37, 37.5, 38, 38.5, 39, 39.5 and check for pressure. The Hodgdon website shows the starting load pressure for the Hornady at 43,200 PSI.

If all went well, I would then drop back to 39 for the Sierras load 39, 39.5, and 40. If all went well, I would start load development at 40 grains and run the OCW protocol. You will need to determine your stop point.

That is just how I would do it, these are matters of personal risk tolerance and you should evaluate the above based on your own experience. I would also ask someone you know who has quick-load or another such program to run the pressure calcs.

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med358-boise said:

I saw the 210 data also. I chose to extrapolate from the 208 because I estimated it would be more similar to the Sierra and was lower.

I personally would start lower than 41. Whenever, I have a scenario like this; I always think of risk verse benefit verse cost. Even if I assess a risk to be very small, I consider the benefit of loading those 6 rounds at a lower weight and the cost. Those six Bergers will do nothing for you in finding a load for the Sierras and are essentially throw aways, but can help tremendously in finding a safer starting point for the Sierras.

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