I use both the large primer(CCI 210) Lapua and the Palma Lapua. I use CCI450 with the Palma brass and, with Berger Hybrids, use exactly the same amount of powder(46grs 2208) in both cases. I can see no discernable difference between the two case/primer combinations. To get the same accuracy with Sierra 2156 155's I again use identical loads in both which is 46.4grs 2208. My loads would differ from yours, they are only quoted to show the different amount of 2208 needed with the different projectiles. All 155's are not equally accurate with the same load.
Michael, the issue is not so much that one can get a superior tune out of large or small primers, as Ray rightly indicates the charge is identical for the same result. Of course choosing the right powder/primer combination for your load density can skew results irrespective of size. Primer size does not matter so much, so long as the wick does not fizz the charge.
What is of more importance is you can preserve case life with smaller primers because there is more brass around the hole. This saves you breaking in new cases and revisiting the tune more often. This also means you can use hotter loads for long distance. Some people do not run at minimum headspace, but at maximum match headspace, so their cases can hold a tad more. Of course, "field" headspace is longer again but an inappropriate use under our rules. Your load is very similar to Tatt's old one, and is safe and accurate in a tight barrel that is .3060-3065" with a throat of .3085". I prefer the .308's with 155's/156's to have a groove/bore of .3075/298 for tangent ogives and for secant pills with a longer body and for heavy pills a groove/bore of .308/300 and all governed by the twist rate appropriate to the location at which you are shooting because of the variance in general air density. The longer body a projectile has, the greater the friction and pressure being the reason for increasing bore size.
My loads vary from 46 grains 2208 to 46.6 depending on atmospheric density. Bendigo liked 46, Rosedale liked 46.6 and Moe liked 46.3.
Of course tighter barrels create greater peak pressure in the throat, but the projectile does not go faster because of this, only the danger of catastrophic failure rises. This was the reason for the introduction of the Bisley 150 rule based on the British Consortium trials. Significant bullet velocity is lost swaging the bullet down in the throat to fit the tight bore compared to an optimum size. The tests I conducted with project Penumbra were aimed at finding that optimum relationship between projectile and bore for velocity and accuracy for the old Sierra 155. Generally, bigger bores go faster if there is sufficient gas seal.
I NEED MORE POWDER. NOT MUCH, PROBABLY .2 TO .4 GRAINS.
A Queens event is always a good place to try out some new loads. Basically I needed to be running 45.2 or even slightly higher to tighten the group. Group size was around 3/4 MOA with the SR Magnum Primer against 1/3 MOA with the LR Primer higher loads.
I found 27 rounds of good ammo lying around in the car on the last day, and put it to good use proving the point.
I'll load the left overs up a little for the up coming Pennant, and confirm that is what is needed.
Summary:
LR Fed 210M with 45.2gn 2208 EQUALS SR CCI 450 with 45.3gn 2208
Your original post stated 54.2grs 2208 and I am surprised that, even with a tight barrel, that gets you out to 800 metres without losing stability. The lowest load that I have ever used, even in a tight barrel, has been 45.6 grs 2208! With the Palma brass, you can push a 155gr projectile a bit faster without destroying the brass(but only if your action is up to it). Personally, I would be moving straight to 45.6grs as a starting point as I have found that was the minimum needed, even in one of my tight barrels on an old Omark used many years ago. The final load can only be determined by you and what pressure signs you observe(if any?). I see that your Palma brass is shooting 3/4moa as against the LR primer shooting 1/3rd moa and there is only 0.1grs difference in load. This is contrary to all my observations which I have consistently proven in shooting the same load in both cases for over 3(?) years, and which David has backed up in his post directly after mine. I only neck size so neck tension is not an issue with my 308's regardless of number of firings.(personal opinion only). Ray.
Hello ,this is my 308 load that I use from 300- 900 yards , lapua case, large cci br2 primer , 45.0 of ar2208 and the longer HBC 155 grain bullet at 74.2mm o.a.l . I have a omark action in a loniel weeks stock and a tse 30 inch stainless barrel in a 1 in 13 twist . and love it I wish I could put pics up , but still can not work it out on this site
I have tried to comment on this subject. But somehow failed,the long and short of it was that 0.5 grains of powder is the difference between Palma brass and large rifle Lapua brass. As I see it,all barrels and chambers give different results,so it isn't wise to be dogmatic about judging quoted loads as excessive or that weak they are useless.
2208 powder
I wish I could put pics up , but still can not work it out on this site 
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